Visual Basic Source Code

Web Browser Sample Code on Visual Basic 2010

2012-03-14T22:54:00.002-07:00

This code illustrate on how to use the web browser control in Visual Basic 2010. It uses the following events and command:
WebBrowser1.IsBusy, WebBrowser1.Document.Body.InnerHtml, WebBrowser1.Navigate, WebBrowser1.CanGoBack, WebBrowser1.CanGoForward, WebBrowser1.IsBusy, WebBrowser1.Refresh
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Screenshot

2012-03-05T04:38:00.000-08:00

Visual Basic 2010 sample code on how to check com port, checking modem, send AT command and send USER command. Download Project

Visual Basic Source Code

.Imports System.Text

Public Class MainForm

' Declare necessary class variables.

Private CommPort As New RS232()

Private IsModemFound As Boolean = False

Private ModemPort As Integer = 0

' This subroutine checks for available ports on the local machine. It does

' this by attempting to open ports 1 through 4.

Private Sub CheckForPortsButton_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles CheckForPortsButton.Click

' Check for Availability of each of the 4 Comm Ports, and

' place a check in the list box items that have openable ports.

Dim i As Integer

For i = 1 To 4

WriteMessage("Testing COM" + i.ToString())

If IsPortAvailable(i) Then

' Check the box for available ports.

Me.PortsList.SetItemChecked(i - 1, True)

Else

' Uncheck the box for unavailable ports.

Me.PortsList.SetItemChecked(i - 1, False)

End If

' Enable the Find Modems button.

Me.CheckModemsButton.Enabled = True

End Sub

' This subroutine attempts to send an AT command to any active Comm Ports.

' If a response is returned then a usable modem has been detected

' on that port.

Private Sub CheckModemsButton_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles CheckModemsButton.Click

Dim i As Integer

For i = 0 To 3

If Me.PortsList.GetItemChecked(i) Then

' Item is checked so it MIGHT be a valid port.

' Test for validity.

If IsPortAvailable(i + 1) Then

' Check if port responds to an AT command.

If IsPortAModem(i + 1) Then

' Set the class variables to the last modem found.

Me.IsModemFound = True

Me.ModemPort = i + 1

' Write message to the user.

WriteMessage("Port " + (i + 1).ToString() + _

" is a responsive modem.")

Else

' Write message to the user.

WriteMessage("Port " + (i + 1).ToString() + _

" is not a responsive modem.")

End If

' If a modem was found, enable the rest of the buttons, so the user

' can interact with the modem.

If Me.IsModemFound Then

Me.SelectedModemTextbox.Text = "Using Modem on COM" + _

Me.ModemPort.ToString()

Me.UserCommandTextbox.Enabled = True

Me.SendATCommandButton.Enabled = True

Me.SendUserCommandButton.Enabled = True

End If

End Sub

' This subroutine clears the TextBox.

Private Sub ClearButton_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ClearButton.Click

Me.StatusTextbox.Clear()

End Sub

' This subroutine sends an AT command to the modem, and records its response.

' It depends on the timer to do the reading of the response.

Private Sub SendATCommandButton_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles SendATCommandButton.Click

' Always wrap up working with Comm Ports in exception handlers.

Try

' Enable the timer.

Me.tmrReadCommPort.Enabled = True

' Attempt to open the port.

CommPort.Open(ModemPort, 115200, 8, RS232.DataParity.Parity_None, _

RS232.DataStopBit.StopBit_1, 4096)

' Write an AT Command to the Port.

CommPort.Write(Encoding.ASCII.GetBytes("AT" & Chr(13)))

' Sleep long enough for the modem to respond and the timer to fire.

System.Threading.Thread.Sleep(200)

Application.DoEvents()

CommPort.Close()

Catch ex As Exception

' Warn the user.

MessageBox.Show("Unable to communicate with Modem")

Finally

' Disable the timer.

Me.tmrReadCommPort.Enabled = False

End Try

End Sub

' This subroutine sends a user specified command to the modem, and records its

' response. It depends on the timer to do the reading of the response.

Private Sub SendUserCommandButton_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles SendUserCommandButton.Click

' Always wrap up working with Comm Ports in exception handlers.

Try

' Enable the timer.

Me.tmrReadCommPort.Enabled = True

' Attempt to open the port.

CommPort.Open(ModemPort, 115200, 8, RS232.DataParity.Parity_None, RS232.DataStopBit.StopBit_1, 4096)

' Write an user specified Command to the Port.

CommPort.Write(Encoding.ASCII.GetBytes(Me.UserCommandTextbox.Text & Chr(13)))

' Sleep long enough for the modem to respond and the timer to fire.

System.Threading.Thread.Sleep(200)

Application.DoEvents()

CommPort.Close()

Catch ex As Exception

' Warn the user.

MessageBox.Show("Unable to communicate with Modem")

Finally

' Disable the timer.

Me.tmrReadCommPort.Enabled = False

End Try

End Sub

' This subroutine is fired when the timer event is raised. It writes whatever

' is in the Comm Port buffer to the output window.

Private Sub tmrReadCommPort_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles tmrReadCommPort.Tick

Try

' As long as there is information, read one byte at a time and

' output it.

While (CommPort.Read(1) <> -1)

' Write the output to the screen.

WriteMessage(Chr(CommPort.InputStream(0)), False)

End While

Catch exc As Exception

' An exception is raised when there is no information to read.

' Don't do anything here, just let the exception go.

End Try

End Sub

' This function checks to see if the port is a modem, by sending

' an AT command to the port. If the port responds, it is assumed to

' be a modem. The function returns a Boolean.

Private Function IsPortAModem(ByVal port As Integer) As Boolean

' Always wrap up working with Comm Ports in exception handlers.

Try

' Attempt to open the port.

CommPort.Open(port, 115200, 8, RS232.DataParity.Parity_None, _

RS232.DataStopBit.StopBit_1, 4096)

' Write an AT Command to the Port.

CommPort.Write(Encoding.ASCII.GetBytes("AT" & Chr(13)))

' Sleep long enough for the modem to respond.

System.Threading.Thread.Sleep(200)

Application.DoEvents()

' Try to get info from the Comm Port.

Try

' Try to read a single byte. If you get it, then assume

' that the port contains a modem. Clear the buffer before

' leaving.

CommPort.Read(1)

CommPort.ClearInputBuffer()

CommPort.Close()

Return True

Catch exc As Exception

' Nothing to read from the Comm Port, so set to False

CommPort.Close()

Return False

End Try

Catch exc As Exception

' Port could not be opened or written to.

Me.PortsList.SetItemChecked(port - 1, False)

MsgBox("Could not open port.", MsgBoxStyle.OKOnly, Me.Text)

Return False

End Try

End Function

' This function attempts to open the passed Comm Port. If it is

' available, it returns True, else it returns False. To determine

' availability a Try-Catch block is used.

Private Function IsPortAvailable(ByVal ComPort As Integer) As Boolean

Try

CommPort.Open(ComPort, 115200, 8, RS232.DataParity.Parity_None, _

RS232.DataStopBit.StopBit_1, 4096)

' If it makes it to here, then the Comm Port is available.

CommPort.Close()

Return True

Catch

' If it gets here, then the attempt to open the Comm Port

' was unsuccessful.

Return False

End Try

End Function

' This subroutine writes a message to the txtStatus TextBox.

Private Sub WriteMessage(ByVal message As String)

Me.StatusTextbox.Text += message + vbCrLf

End Sub

' This subroutine writes a message to the txtStatus TextBox and allows

' the line feed to be suppressed.

Private Sub WriteMessage(ByVal message As String, ByVal linefeed As Boolean)

Me.StatusTextbox.Text += message

If linefeed Then

Me.StatusTextbox.Text += vbCrLf

End If

End Sub

Private Sub ExitToolStripMenuItem_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ExitToolStripMenuItem.Click

End

End Sub

End Class

Connect to SQL Azure Using ADO.NET

2011-11-26T22:35:00.000-08:00

Sample code using ADO.NET to connect to a database in Microsoft SQL Azure Database is very similar to connecting to an instance of SQL Server on your premises

Using this Example

To use this example in Visual Studio with your SQL Azure server, do the following steps:

Open Visual Studio and create a new console application.
Replace the code in the program file with the code from this example.
Replace <ProvideUserName> with the name of an SQL Azure Database login that has been assigned the dbmanager role. Note: if you use the login@server username format, the server portion of the name must match the first part of the server's fully qualified name. For example, if your server is servername.database.windows.net, your login name will look like loginname@servername. For more information about SQL Azure Database roles.
Replace <ProvidePassword> with the password associated with the login. Note: We recommend using a strong password when creating a login.
Replace <ProvideServerName> with the fully qualified domain name of your SQL Azure server. For example: servername.database.windows.net
Replace <ProvideDatabaseName> with the name of the database you want the code to create.
Run the code.

' Sample Code

Option Explicit On

Option Strict On

Imports System

Imports System.Collections.Generic

Imports System.Linq

Imports System.Text

Imports System.Data.SqlClient

Imports System.Data

Module Program

' Provide the following information

Private ReadOnly userName As String = "<ProvideUserName>"

Private ReadOnly password As String = "<ProvidePassword>"

Private ReadOnly dataSource As String = "<ProvideServerName>"

Private ReadOnly sampleDatabaseName As String = "<ProvideDatabaseName>"

Sub Main()

' Create a connection string for the master database

Dim connString1Builder As New SqlConnectionStringBuilder()

With connString1Builder

.DataSource = dataSource

.InitialCatalog = "master"

.Encrypt = True

.TrustServerCertificate = False

.UserID = userName

.Password = password

End With

' Create a connection string for the sample database

Dim connString2Builder As New SqlConnectionStringBuilder()

With connString2Builder

.DataSource = dataSource

.InitialCatalog = sampleDatabaseName

.Encrypt = True

.TrustServerCertificate = False

.UserID = userName

.Password = password

End With

' Connect to the master database and create the sample database

Using conn As New SqlConnection(connString1Builder.ToString())

Using command As SqlCommand = conn.CreateCommand()

conn.Open()

' Create the sample database

Dim cmdText As String

cmdText = String.Format("CREATE DATABASE {0}", _

sampleDatabaseName)

command.CommandText = cmdText

command.ExecuteNonQuery()

conn.Close()

End Using

' Connect to the sample database and perform various operations

Using conn As New SqlConnection(connString2Builder.ToString())

Using command As SqlCommand = conn.CreateCommand()

conn.Open()

' Create a table

command.CommandText = "CREATE TABLE T1(Col1 int primary key, Col2 varchar(20))"

command.ExecuteNonQuery()

' Insert sample records

command.CommandText = "INSERT INTO T1 (col1, col2) VALUES (1, 'string 1'), (2, 'string 2'), (3, 'string 3')"

Dim rowsAdded As Integer = command.ExecuteNonQuery()

' Query the table and print the results

command.CommandText = "SELECT * FROM T1"

Using reader As SqlDataReader = command.ExecuteReader()

' Loop over the results

While reader.Read()

Console.WriteLine("Col1: {0}, Col2: {1}", _

reader("Col1").ToString().Trim(), _

reader("Col2").ToString().Trim())

End While

End Using

' Update a record

command.CommandText = "UPDATE T1 SET Col2='string 1111' WHERE Col1=1"

command.ExecuteNonQuery()

' Delete a record

command.CommandText = "DELETE FROM T1 WHERE Col1=2"

command.ExecuteNonQuery()

' Query the table and print the results

Console.WriteLine("After update/delete, the table has these records...")

command.CommandText = "SELECT * FROM T1"

Using reader As SqlDataReader = command.ExecuteReader()

' Loop over the results

While reader.Read()

Console.WriteLine("Col1: {0}, Col2: {1}", _

reader("Col1").ToString().Trim(), _

reader("Col2").ToString().Trim())

End While

End Using

conn.Close()

End Using

Console.WriteLine("Press Enter to continue...")

Console.ReadLine()

End Sub

End Module

How to Read Oracle Database from Visual Basic .Net

2011-11-26T01:37:00.000-08:00

Visual Basic .Net 2010 sample on how to connect and read data from Oracle Server.

Before starting this tutorial, you should install Microsoft Visual Studio 2010, Install Oracle Database 9.2 or later or Oracle Database XE and install Oracle 11g Oracle Data Access Components (ODAC) with Oracle Developer Tools for Visual Studio version 11.2.0.1.2 or later from OTN.

'Add the following VB.NET Imports statements before the Public Class declaration.

Imports System.Data

Imports Oracle.DataAccess.Client ' ODP.NET Oracle managed provider

Imports Oracle.DataAccess.Types

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click

Dim oradb As String = "Data Source=orcl;User Id=hr;Password=hr;"

Dim conn As New OracleConnection(oradb)

conn.Open()

Dim cmd As New OracleCommand

cmd.Connection = conn

cmd.CommandText = "select dept_name from departments where dept_id = 80"

cmd.CommandType = CommandType.Text

Dim dr As OracleDataReader = cmd.ExecuteReader()

dr.Read()

Text1.Text = dr.Item("dept_name")

conn.Dispose()

End Sub

How to Connect Database Using ODBC (Object Database Configuration/Connectivity)

2011-06-29T03:33:00.000-07:00

This ODBC method is applicable to Visual Basic .Net and Visual Basic 6.0 using MS Access Databse (.mdb). Please follow the instructions below on how to setup database.
1. Click Start button, and select Control Panel

2. Once the control panel open, please double click Administrative Tools.

Note: If you can't locate the the administrative tools, please select Classic View at the left side of the control panel pane.

3. Under the Administrative Tools, double click to select the Data Sources (ODBC) as shown the image below. After selecting the Data Sources, the ODBC panel window will display.

4. Now we are going to add new datasebase, click Add button and new window willl appear "Create New Data Source", select the Driver do Microsoft Access (*.mdb) for MS Access, click Finish Button.

5. We're almost done, let's configure the ODBC for MS Access, under Data Source Name, type the MyDatabase, please leave blank the description it's optinal. Now, let's select the path of your database .mdb once you found it select OK button.

6. The image shown below that the Database .mdb is successfully located. Click OK button to Finish the configuration. (MS Access Database Configuration done).

7. Done! You are now ready to connect your visual basic program using this ODBC setup.

Connection Strings for SQL Server 2000 and 7.0

2011-06-29T00:51:00.000-07:00

.NET Framework Data Provider for SQL Server

Standard Security
Data Source=ServerName;Initial Catalog=DatabaseName;User Id=UserName;Password=Password;

Standard Security alternative syntax
Server=ServerName;Database=DatabaseName;User ID=UserName;Password=Password;Trusted_Connection=False;

Trusted Connection

Data Source=ServerName;Initial Catalog=DatabaseName;Integrated Security=SSPI;

Connecting to an SQL Server instance

Server=ServerName\theInstanceName;Database=DatabaseName;Trusted_Connection=True;

Trusted Connection from a CE device

Data Source=ServerName;Initial Catalog=DatabaseName;Integrated Security=SSPI;User ID=myDomain\UserName;Password=Password;

Note: This will work on a CE device only.

Connect via an IP address

Data Source=190.190.200.100,1433;Network Library=DBMSSOCN;Initial Catalog=DatabaseName;User ID=UserName;Password=Password;

DBMSSOCN=TCP/IP.

Note: 1433 is the default port for SQL Server.

Microsoft OLE DB Provider for SQL Server

Standard Security

Provider=sqloledb;Data Source=ServerName;Initial Catalog=DatabaseName;User Id=UserName;Password=Password;

Trusted connection

Provider=sqloledb;Data Source=ServerName;Initial Catalog=DatabaseName;Integrated Security=SSPI;

Connecting to an SQL Server instance

Provider=sqloledb;Data Source=ServerName\theInstanceName;Initial Catalog=DatabaseName;Integrated Security=SSPI;

Connect via an IP address

Provider=sqloledb;Data Source=190.190.200.100,1433;Network Library=DBMSSOCN;Initial Catalog=DatabaseName;User ID=UserName;Password=Password;

DBMSSOCN=TCP/IP.

This use to connect the SQL Server Database via internet connection.

ADO Control to create Database Table using Visual Basic

2011-04-07T05:31:00.000-07:00

'Using ADO control to create a database table from Visual Basic

'Connect to the database file and use the Connection object's Execute method to

'execute an SQL CREATE TABLE statement.

Private Sub BtnCreate_Click()

Dim db_file As String

Dim Conn_Data As ADODB.Connection

Dim rs_Data As ADODB.Recordset

Dim num_records As Integer

' Get the database name.

db_file = App.Path

If Right$(db_file, 1) <> "\" Then db_file = db_file & "\"

db_file = db_file & "People.mdb"

' Open a Conn_Dataection.

Set Conn_Data = New ADODB.Connection

Conn_Data.ConnectionString = "Provider=Microsoft.Jet.OLEDB.4.0;" & "Data Source=" & db_file & ";" & _

"Pers_Dataist Security Info=False"

Conn_Data.Open

' Drop the Employees table if it already exists.

On Error Resume Next

Conn_Data.Execute "DROP TABLE Employees"

On Error GoTo 0

' Create the Employees table.

Conn_Data.Execute "CREATE TABLE EmployeesTable(" & "EmployeeId INTEGER NOT NULL," & _

"LastName VARCHAR(40) NOT NULL," & "Firs_DatatName VARCHAR(40) NOT NULL)"

' Populate the table.

Conn_Data.Execute "INSERT INTO EmployeesTable VALUES (1, " & "'Anders_Dataon', 'Amy')"

Conn_Data.Execute "INSERT INTO EmployeesTable VALUES (1, 'Baker', " & " 'Betty')"

Conn_Data.Execute "INSERT INTO EmployeesTable VALUES (1, 'Cover', " & " 'Chauncey')"

' Add more records ...

' See how many records the table contains.

Set rs_Data = Conn_Data.Execute("SELECT COUNT (*) FROM EmployeesTable")

num_records = rs_Data.Fields(0)

Conn_Data.Close

MsgBox "Created " & num_records & " records", vbInformation, "Done"

End Sub

Password Generator in Visual Basic

2011-04-01T08:28:00.000-07:00

'A sample visual code on how to generate a best random password generator

Public Function GeneratePassword(ByVal lngLength As Long) _

As String

On Error GoTo Err_Proc

Dim iChr As Integer

Dim c As Long

Dim strResult As String

Dim iAsc As String

Randomize Timer

For c = 1 To lngLength

'Randomly decide what set of ASCII chars we will use

iAsc = Int(3 * Rnd + 1)

'Randomly pick a char from the random set

Select Case iAsc

Case 1

iChr = Int((Asc("Z") - Asc("A") + 1) * Rnd + Asc("A"))

Case 2

iChr = Int((Asc("z") - Asc("a") + 1) * Rnd + Asc("a"))

Case 3

iChr = Int((Asc("9") - Asc("0") + 1) * Rnd + Asc("0"))

Case Else

Err.Raise 20000, , "GeneratePassword has a problem."

End Select

strResult = strResult & Chr(iChr)

Next c

GeneratePassword = strResult

Exit_Proc:

Exit Function

Err_Proc:

MsgBox Err.Number & ": " & Err.Description, _

vbOKOnly + vbCritical

GeneratePassword = vbNullString

Resume Exit_Proc

End Function

Connect Oracle Database using Visual Basic

2011-03-24T05:27:00.001-07:00

'How to connect Oracle Database from Visual Basic

'Sample code and connection strings to connect Oracle using Visual Basic:

Dim conn As ADODB.Connection

' Open a Conn_Dataection using Oracle ODBC.

Set Conn_Data = New ADODB.Connection

Conn_Data.ConnectionString = "Driver={Microsoft ODBC for Oracle};" & "UID=user_name;PWD=user_passsword"

Conn_Data.Open

'Open the table as in:

Dim rs_Data As ADODB.Recordset

' Open the table.

Set rs_Data = New ADODB.Recordset

rs_Data.Open "TableName", Conn_Data, adOpenDynamic, adLockOptimistic, adCmdTable

'Enter the user name password and table name as per the database.

'it must be valid one.

'To reads the data from the table and displays the values in a ListBox

' List the data.

Do While Not rs_Data.EOF

txt = ""

For Each fld In rs_Data.Fields

txt = txt & Trim$(fld.Value) & ", "

Next fld

If Len(txt) > 0 Then txt = Left$(txt, Len(txt) - 2)

List1.AddItem txt

rs_Data.MoveNext

Loop

'Finally close the recordset and close the Conn_Dataection:

rs_Data.Close

Conn_Data.Close

How to Use ADO Object to get data from a read only MS Access database

2011-03-22T05:21:00.000-07:00

'How to Use ADO object to get data from a read-only MS Access database

'In the ConnDataect string, set Mode to Read.

Dim ConnData As ADODB.Connection

' Open a ConnDataection.

Set ConnData = New ADODB.Connection

ConnData.ConnectionString = "Provider=Microsoft.Jet.OLEDB.4.0;" & "Data Source=" & db_file & ";" & _

"Mode=Read;" & "PeRecordset1ist Security Info=False"

ConnData.Open

'This example reads data and displays the values in a List Box object.

Dim Recordset1 As ADODB.Recordset

' Open the Database Recordset.

Set Recordset1 = ConnData.Execute("SELECT * FROM Books", , adCmdText)

' List the data.

Do While Not Recordset1.EOF

' The following statement would cause an

' error because the ConnDataection is read-only.

' Recordset1!Title = "XXX"

txt = ""

For Each fld In Recordset1.Fields

txt = txt & Trim$(fld.Value) & vbTab

Next fld

If Len(txt) > 0 Then txt = Left$(txt, Len(txt) - 1)

List1.AddItem txt

Recordset1.MoveNext

Loop

Recordset1.Close

ConnData.Close

How to Copy data from an Access database and save in Excel spreadsheet

2011-03-20T10:31:00.000-07:00

'How to Copy data from an Access database into an Excel spreadsheet

'Use ADO object to open the database. Using Excel as a server, open the spreadsheet.

'Read the field names from the ADO Recordset data and add them to the first row in

'the spreadsheet to make column headers.

'To enable excel application please add excel object first.

Private Sub Form_Load()

Dim cSource_Data As String

Dim cTarget_Data As String

Dim oCon As ADODB.Connection

Dim cSQL As String

cSource_Data = App.Path & IIf(Right$(App.Path, 1) <> "\", "\", "") & "books.mdb"

cTarget_Data = App.Path & IIf(Right$(App.Path, 1) <> "\", "\", "") & "Books.xls].[Table1]"

Set oCon = New ADODB.Connection

With oCon

.ConnectionString = "Provider=Microsoft.Jet.OLEDB.4.0;" & "Data Source=" & cSource_Data & _

";" & "Persist Security Info=False"

.Open

cSQL = "SELECT [Title],[URL],[ISBN],[Picture],[Pages],[CD],[Year] INTO " & _

"[Excel 8.0;Database=" & cTarget_Data & " FROM [Books]"

.Execute cSQL

End With

End Sub

How to Use ADO object and populate result in a ListBox object

2011-03-20T10:28:00.000-07:00

Database - How to Use ADO to populate a ListBox Obkect with data values

'Open a Recordset that selects the desired information. Loop through the records and put the values to the ListBox.

Dim statement As String

Dim Conn_Data As ADODB.Connection

Dim rs_data As ADODB.Recordset

' db_file contains the Access database's file name.

' Open a Conn_Dataection.

Set Conn_Data = New ADODB.Connection

Conn_Data.ConnectionString = "Provider=Microsoft.Jet.OLEDB.4.0;" & "Data Source=" & db_file & ";" & _

"Pers_dataist Security Info=False"

Conn_Data.Open

' Select the data.

statement = "SELECT Title, URL FROM Books ORDER BY " & "Title"

' Get the records.

Set rs_data = Conn_Data.Execute(statement, , adCmdText)

' Load the Title field into the List Box Oject.

' Save the URL values in a collection.

Set URLs = New Collection

Do While Not rs_data.EOF

List1.AddItem rs_data!Title

URLs.Add CStr(rs_data!URL)

rs_data.MoveNext

Loop

' Close the recordset and Conn_Dataection.

rs_data.Close

Conn_Data.Close

'This example saves the URL value for each record in a collection. When you

'click on a ListBox item, the program displays the URL in a Label. When you

'double click on a ListBox item, the program displays the corresponding Web

'document in a browser.

' Display the item's URL.

Private Sub List1_Click()

If List1.ListIndex < 0 Then

Label1.Caption = ""

Else

Label1.Caption = URLs(List1.ListIndex + 1)

End If

End Sub

' Display the item's Web document.

Private Sub List1_DblClick()

If List1.ListIndex >= 0 Then

ShellExecute hWnd, "open", URLs(List1.ListIndex + 1), vbNullString, vbNullString, SW_SHOW

End If

End Sub

Sample Code on How to Fill the Datagrid View in Visual Basic.Net

2011-03-20T07:32:00.000-07:00

Sample on how to Fill the Datagrid View in Visual Basic .Net

'Here's the code below.

Dim query as string="Select * from EmployeeTable"
Dim da as new oledbdataadapter(query,con)

dim ds as new dataset

da.fill(ds,"EmployeeTable")

me.dgv.datasource=ds
me.dgv.datamember="EmployeeTable"

ds.dispose

con.close

Visual Basic SQL Select Statemnt

2011-03-20T07:16:00.000-07:00

The SELECT statement is used to select data from a database.

The result is stored in a result table, called the result-set.

SQL SELECT Syntax is

This statement select only one column of the database field.

SELECT column_name(s) FROM table_name

This SQL statement select all the fields of the database using the (*) asterisk

SELECT * FROM table_name

Here's the sample SQL statement below.

Figure 1

Select IDNo,LastName,FirstName,MI FROM EmployeeTbl Where IDNo= '12345'

Figure 2

Select * FROM EmployeeTbl Where IDNo='12345'

A SQL SELECT statement can be broken down into numerous elements, each beginning with a keyword. Although it is not necessary, common convention is to write these keywords in all capital letters. In this article, we will focus on the most fundamental and common elements of a SELECT statement, namely

SELECT
FROM
WHERE
ORDER BY

The SELECT ... FROM Clause

The most basic SELECT statement has only 2 parts: (1) what columns you want to return and (2) what table(s) those columns come from.
If we want to retrieve all of the information about all of the customers in the Employees table, we could use the asterisk (*) as a shortcut for all of the columns, and our query looks like

SELECT * FROM Employees

If we want only specific columns (as is usually the case), we can/should explicitly specify them in a comma-separated list, as in

SELECT EmployeeID, FirstName, LastName, HireDate, City FROM EmployeesTable

The WHERE Clause

The next thing we want to do is to start limiting, or filtering, the data we fetch from the database. By adding a WHERE clause to the SELECT statement, we add one (or more) conditions that must be met by the selected data. This will limit the number of rows that answer the query and are fetched. In many cases, this is where most of the "action" of a query takes place.
We can continue with our previous query, and limit it to only those employees living in London:
SELECT EmployeeID, FirstName, LastName, HireDate, City FROM Employees WHERE City = 'London'

The ORDER BY Clause

Until now, we have been discussing filtering the data: that is, defining the conditions that determine which rows will be included in the final set of rows to be fetched and returned from the database. Once we have determined which columns and rows will be included in the results of our SELECT query, we may want to control the order in which the rows appear—sorting the data.
To sort the data rows, we include the ORDER BY clause. The ORDER BY clause includes one or more column names that specify the sort order. If we return to one of our first SELECT statements, we can sort its results by City with the following statement:

SELECT EmployeeID, FirstName, LastName, HireDate, City FROM EmployeesTable
ORDER BY City

How to load the values of a recordset in a combo box object

2011-03-20T05:04:00.000-07:00

'How to load the values of a recordset in a combo box object

Public Sub FillData_ListBox(ByRef lstControl As Object, ByRef strQry As String)

'this routine is used to fill up a list box by passing 'the lstbox name and

'query

Dim lstCtrlObj As Object

Dim Rst As ADODB.Recordset

On Error GoTo VBError

Set Rst = New ADODB.Recordset

With Rst

.Source = strQry

.Open , AdoComp, adOpenDynamic, adLockReadOnly

End With

Set lstCtrlObj = lstControl

lstCtrlObj.Clear

If Rst.EOF = False Then

Rst.MoveFirst

While Rst.EOF = False

lstCtrlObj.AddItem Rst.Fields(1)

lstCtrlObj.ItemData(lstCtrlObj.NewIndex) = Rst.Fields(0)

Rst.MoveNext

Wend

itsRecCount = 1

itsProcessClickFlag = True

lstCtrlObj.ListIndex = 0

End If

Done:

Rst.Close

Set Rst = Nothing

Exit Sub

VBError: ' Non-ADO error handler

DisplayVBError

GoTo Done

End Sub

Sample on how to create and call a stored procedure.

2011-03-19T05:02:00.000-07:00

'How to create and call a stored procedure.

Dim conn As ADODB.Connection

Dim rst As ADODB.Recordset

CREATE PROCEDURE ProcEmployees As

Begin

declare @Empcount as int

Select @EmpCount = count(*) From EmployeesTable

Return @Empcount

End

Set conn = New ADODB.Connection

Set rst = New ADODB.Recorset

conn.Provider = "Microsoft Jet 4.0 OLE DB Provider"

conn.Open "Data Source=c:\Data1.mdb"

rst = conn.execute "Call ProcEmployees"

How to Connect to a database using ADO type and retrieving the data.

2011-03-18T04:58:00.000-07:00

'How to Connect to a database using ADO and retrieving the data.

'Create a reference to 'Microsoft ActiveX Data Object 2.0 Library'

Private Sub Form_Load()

'Declare the connection and recordset objects

Dim cnData As Connection

Dim recordset1 As Recordset

'Instantiate the objects

Set Conn = New Connection

Set recordset1 = New Recordset

'Set the connection string

Conn.ConnectionString = "Provider=Microsoft.Jet.OLEDB.4.0; Data Source=<<PATH TO DATABASE>>"

Conn.Open

'Code to test the connection

If Conn.State = adStateOpen Then MsgBox "Connection good."

'Get data from the database connection

recordset1.Open "<<SQL STATEMENT>>", Conn

'For testing purposes, write to debug window

Debug.Print recordset1!<<DATABASE_COLUMN_FIELD_NAME>>

'Make sure to close the connection and release Conn

Conn.Close

Set Conn = Nothing

End Sub

How to Bind Text Boxes to an ADO Recordset during run time.

2011-03-18T04:43:00.000-07:00

'Sample on How to Bind TextBoxes to an ADO Recordset at run time

'Open the ADO Connection and the Recordset to fetch the data. Set the TextBox's

'DataSource properties to the Recordset. Set their DataField properties to the

'names of the Recordset's fields to bind.

Private Sub Form1_Load()

Dim data_file As String

' Get the database file name.

data_file = App.Path

If Right$(data_file, 1) <> "\" Then data_file = data_file & "\"

data_file = data_file & "Data.mdb"

' Open the database connection.

Set m_Conn = New ADODB.Connection

m_Conn.ConnectionString = "Provider=Microsoft.Jet.OLEDB.4.0;" & "Data Source=" & data_file & _

";" & "Persist Security Info=False"

m_Conn.Open

' Fetch the Books records.

Set Recordset1 = New ADODB.Recordset

Recordset1.Open "SELECT * FROM Books ORDER BY Title", m_Conn, adOpenDynamic, _

adLockBatchOptimistic

' Bind the TextBoxes to the Recordset.

Set textTitle.DataSource = Recordset1

textTitle.DataField = "Title"

Set txtURL.DataSource = Recordset1

txtURL.DataField = "URL"

End Sub

'The program can use the Recordset's MovePrevious, MoveNext, and other

'navigation methods to display different records in the bound controls.

Private Sub BtnNext_Click()

' Move to the next record.

Recordset1.MoveNext

' Enable the appropriate buttons.

EnableButtons

End Sub

Private Sub BtnPrev_Click()

' Move to the previous record.

Recordset1.MovePrevious

' Enable the appropriate buttons.

EnableButtons

End Sub

' Enable the appropriate buttons.

Private Sub EnableButtons()

BtnNext.Enabled = Not Recordset1.EOF

BtnPrev.Enabled = Not Recordset1.BOF

End Sub

How to Load a Form Dynamically in Visual Basic .Net

2010-06-07T05:39:00.000-07:00

Once you know the name of the DLL and the name of the form you want to show, the rest is quite simple. You create an instance of the form, using the Assembly.CreateInstance method, and then call the Show method on the form. The following code snippet is a simplified version of the code in the DynamicApp Dashboard.Button_Click_Handler method. It demonstrates how to load a DLL called MyDll.dll, create an instance of a form within the DLL Form1, and show the form.

Dim asm As Reflection.Assembly
Dim f As Form
asm = asm.LoadFrom("MyDll.dll")
f = CType(asm.CreateInstance("MyDll.Form1"), Form)
f.Show()

Notice with the CreateInstance method that we have to refer to the form as MyDll.Form1, using the <namespace>.<formname> format. Also be aware that when you write code that loads a DLL dynamically, all names, including the filename and type name, are case sensitive.

Visual Basic 6 - How to Hide Application in Windows Task List

2010-05-18T05:37:00.000-07:00

This code will hide your application in windows tasklist using visual basic when user press the ctr + alt + delete in keyboard. This type of program is very useful if you don't want your users/clients to close the application through windows tasklist.

Here's the code sample below.

Declare Function SetWindowPos Lib "user32" (ByVal hwnd _

As Long, ByVal hWndInsertAfter As Long, ByVal x As Long, _

ByVal y As Long, ByVal cx As Long, ByVal cy As Long, ByVal _

wFlags As Long) As Long

Declare Function FindWindow Lib "user32" Alias _

"FindWindowA" (ByVal lpClassName As String, ByVal _

lpWindowName As String) As Long

Const SWP_HIDEWINDOW = &H80

Const SWP_SHOWWINDOW = &H40

Private Sub Command1_Click()

Dim Thwnd as Long

Thwnd = FindWindow("Shell_traywnd", "")

Call SetWindowPos(Thwnd, 0, 0, 0, 0, 0, SWP_HIDEWINDOW)

End Sub

Private Sub Command2_Click()

Dim Thwnd as Long

Thwnd = FindWindow("Shell_traywnd", "")

Call SetWindowPos(Thwnd, 0, 0, 0, 0, 0, SWP_SHOWWINDOW)

End Sub

How to Create a Hot Key In Visual Basic 6

2010-05-18T05:36:00.000-07:00

What is a Hot Key Control
A hot key is a key combination that the user can press to perform an action quickly. For example, a user can create a hot key that activates a given window and brings it to the top of the z-order. The hot key control displays the user's choices and ensures that the user selects a valid key combination. Here's the code below on how to create a hot key control.

Declare Function SendMessage Lib "user32" Alias _

"SendMessageA" (ByVal hwnd As Long, _

ByVal wMsg As Long, ByVal wParam As Long, _

lParam As Long) As Long

Declare Function DefWindowProc Lib "user32" _

Alias "DefWindowProcA" (ByVal hwnd As Long, _

ByVal wMsg As Long, ByVal wParam As Long, _

ByVal lParam As Long) As Long

Public Const WM_SETHOTKEY = &H32

Public Const WM_SHOWWINDOW = &H18

Public Const HK_SHIFTA = &H141 'Shift + A

Public Const HK_SHIFTB = &H142 'Shift * B

Public Const HK_CONTROLA = &H241 'Control + A

Public Const HK_ALTZ = &H45A

'The value of the key-combination has to

'declared in lowbyte/highbyte-format

'That means as a hex-number: the last two

'characters specify the lowbyte (e.g.: 41 = a),

'the first the highbyte (e.g.: 01 = 1 = Shift)

Private Sub Form_Load()

Me.WindowState = vbMinimized

'Let windows know what hotkey you want for

'your app, setting of lParam has no effect

erg& = SendMessage(Me.hwnd, WM_SETHOTKEY, _

HK_ALTZ, 0)

'Check if succesfull

If erg& <> 1 Then

MsgBox "You need another hotkey", vbOKOnly, _

"Error"

End If

'Tell windows what it should do, when the hotkey

'is pressed -> show the window!

'The setting of wParam and lParam has no effect

erg& = DefWindowProc(Me.hwnd, WM_SHOWWINDOW, _

0, 0)

End Sub

System API Programming

2010-04-27T09:22:00.000-07:00

Visual Basic 6 - API Programming on how to get computer name

'Get Computer Name
Declare Function SetComputerName Lib "kernel32" _
Alias "SetComputerNameA" (ByVal lpComputerName As String) As Long

Private Sub cmdChange_Click()
SetComputerName txtNewName.Text
End Sub

' Check if program running
Private Sub Form_Load()

'// Not the best way to check
'// Better to use the FindWindow API

If App.PrevInstance = True Then
MsgBox ("This program is already running.")
End
End If

End Sub

Using ADO Record Source

2010-04-27T09:15:00.000-07:00

Code on how to use ado record source in visal basic .net

Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
' Create a connection string
Dim ConnectionString As String = "Provider=Microsoft.Jet.OLEDB.4.0; Data Source=c:\\Northwind.mdb"
Dim sql As String = "SELECT CustomerId, CompanyName, ContactName From Customers"

' Create a Connection object and open it
Dim conn As Connection = New Connection()
Dim connMode As Integer = ConnectModeEnum.adModeUnknown
conn.CursorLocation = CursorLocationEnum.adUseServer
conn.Open(ConnectionString, "", "", connMode)
Dim recAffected As Object
Dim cmdType As Integer = CommandTypeEnum.adCmdText
Dim rs As _Recordset = conn.Execute(sql)

' Create dataset and data adpater objects
Dim ds As DataSet = New DataSet("Recordset")
Dim da As OleDbDataAdapter = New OleDbDataAdapter()

' Call data adapter's Fill method to fill data from ADO
' Recordset to the dataset

da.Fill(ds, rs, "Customers")

' Now use dataset
DataGrid1.DataSource = ds.DefaultViewManager

Multi Threading in Visual Basic.Net

2010-04-27T09:13:00.000-07:00

'Sample Code on how to use multithreading in Visual Basic .Net

Imports System

Imports System.Threading

Public Module ThreadSample

Public Balance As Integer = 1000

Sub Main()

Dim account As Account = New Account()

Dim depositeBalance1 As DepositeBalance = New _

DepositeBalance(account, 1000, "Customer 1")

Dim depositeBalance2 As DepositeBalance = New _

DepositeBalance(account, 1000, "Customer 2")

Dim t1 As Thread = New _

Thread(AddressOf depositeBalance1.DepositeAmount)

Dim t2 As Thread = New _

Thread(AddressOf depositeBalance2.DepositeAmount)

t1.Start()

t2.Start()

Try

t1.Join()

t2.Join()

Catch e As Exception

Console.Write(e.ToString())

Finally

'Do Nothing

End Try

End Sub

Public Class Account

Private balanceAmount As Integer

Public Sub Deposite(ByVal amount As Integer, _

ByVal message As String)

Console.Write(message & _

" Depositing Amount " & amount)

Console.Write(message & " Checking Previous Balance")

Monitor.Enter(Me)

balanceAmount = getBalance()

Console.Write(message & _

" Previous Balance in Account " & balanceAmount)

balanceAmount += amount

Console.Write(message & _

" Updating Balance in Account ")

setBalance(balanceAmount)

Monitor.Exit(Me)

Console.Write(message & " Update Balance " & Balance)

End Sub

Private Function getBalance() As Integer

Try

Thread.sleep(1000)

Catch e As Exception

Console.Write(e.ToString())

Finally

'Do Nothing

End Try

Return Balance

End Function

Private Sub setBalance(ByVal amount As Integer)

Try

Thread.sleep(1000)

Catch e As Exception

Console.Write(e.ToString())

Finally

'Do Nothing

End Try

Balance = amount

End Sub

End Class

Public Class DepositeBalance

Private account As Account

Private amount As Integer

Private message As String

Public Sub new(ByRef account As Account, _

ByVal amount As Integer, ByVal message As String)

MyBase.New()

Me.account = account

Me.amount = amount

Me.message = message

End Sub

Public Sub DepositeAmount()

Account.Deposite(amount, message)

End Sub

End Class

End Module

SQL Server 2005 Express - For Visual Basic .Net and 6.0

2010-04-07T20:18:00.000-07:00

The best database server for Microsoft Visual Basic Language is "Microsoft SQL Server" but what's the difference between the Microsoft SQL Server Express and SQL Server. Well, MS SQL Server you need to buy a license from Microsoft Corporation while the MS SQL Server Express or MSDE in previous version it's a FREE database, it means you can use this software without buying a license. However, there's a limitations not to mention all, but one is the size of the database can grow up to four(4) Gigabytes only, for me 4GB database can handle enough for a small company with transactions more or less 1 million records. For more information please visit website here. http://www.microsoft.com/Sqlserver/2005/en/us/express.aspx

I suggest to use this database server for testing your .net applications, .asp or .aspx for website applications because it's easy to configure and use. You can install this software in MS Windows XP, MS Vista and MS Windows 7.

Click the link below to download the software from Microsoft website.

Download the Microsoft SQL Server 2005 Express....