.NET topics

Adding new nodes into XML document using LINQ

2011-10-21T01:28:00.000-07:00

Today example using LINQ with xml, will be used to show example to add new elements in the XML document and to update the existing values of the element nodes.

Using the .Net earlier classes XmlDocument, XmlTextReader,XPathNavigator etc, bulky code was required to traverse through the XML nodes and finding out the node we wanted to modify. But with the help of LINQ, traversing through the XML document is really easy.

Basic definitions:-

a) XDocument class - Represents an XML document.
b) XElement class- Represents an XML element.
c) XDocument.Load method - Creates a new XDocument from a file specified by a URI,
from an TextReader, or from an XmlReader.

Lets start the example to see how modifying and addition of nodes can be achieved with the help of LINQ.

Step 1:-

From my previous example i have copied here the same XML document customer.xml file, which contains the details about the customer. Ex:- Name, CompanyName, JobTitle etc.

<?xml version="1.0" encoding="utf-8" ?>

<Name>B. K. Mishra</Name>

<CompanyName>FIC Limited</CompanyName>

<JobTitle>Sales Representative</JobTitle>

<Address>1st Block, 19th cross,sector 7</Address>

<City>Bangalore</City>

<Country>India</Country>

<EmailId>B.k.mishra@fic.com</EmailId>

</Customer>

<Name>A. K. Mitra</Name>

<CompanyName>Sourcesoft Ltd</CompanyName>

<JobTitle>Maketing Manager</JobTitle>

<Address>Building no-10, second floor,1st block</Address>

<City>Delhi</City>

<Country>India</Country>

<EmailId>AKMitra@sourcesoft.com</EmailId>

</Customer>

<Name>S. Reddy</Name>

<CompanyName>Edge solution</CompanyName>

<JobTitle>Sales Representative</JobTitle>

<Address>Raheja arcade,3rd floor, sector 1</Address>

<City>Bangalore</City>

<Country>India</Country>

<EmailId>SReddy@EdgeSol.com</EmailId>

</Customer>

<Name>K. Manakotte</Name>

<JobTitle>Marketing Manager</JobTitle>

<Address>Citi tower, MG Road</Address>

<City>Bangalore</City>

<Country>India</Country>

<EmailId>k.manakotte@info.com</EmailId>

</Customer>

</Customers>

Step 2:-

Now i will be writing the code in code behind file to load the xml document and then to add element to the existing xml tree.

XDocument xDoc = XDocument.Load("Customers.xml");

//retrieving the maximum value of Id attribute from the customer node

var maxID = (from p in xDoc.Descendants("Customer")

select p.Attribute("Id").Value).Max();

//incrementing the ID value by 1

int newID = Convert.ToInt16(maxID)+1;

//creating a new customer element with Id attribute having newly created Id value

// then creating all the child elementes with respected value to each node

XElement xeCustomer = new XElement("Customer", new XAttribute("Id", newID + 1),

new XElement("Name", "Stephen Smith"),

new XElement("CompanyName", "Nous System"),

new XElement("JobTitle", "Marketing Manager"),

new XElement("Address", "Sky arcade,Karol Bagh"),

new XElement("City", "Delhi"),

new XElement("Country", "India"),

new XElement("Fax", "011-23455555"),

new XElement("EmailId", "steve.smith@nous.com"));

//adding the newly created XElement to the xDoc object parent xml tree

xDoc.Element("Customers").Add(xeCustomer);

//Retrieving all the customer details from the xDoc

var customerList = from cust in xDoc.Descendants("Customer")

select new

{

CustomerName = cust.Element("Name").Value,

JobTitle = cust.Element("JobTitle").Value,

Fax = cust.Element("Fax").Value,

EmailId = cust.Element("EmailId").Value

};

//displaying the customer details in the

foreach (var cust in customerList)

{

Console.WriteLine(cust.CustomerName + ";" + cust.JobTitle + ";" + cust.Fax + ";" +

cust.EmailId);

}

Output

After creation of new elements, the xDoc object can be passed to any database for record creation or can be used to write Xml document into a new file.

I hope this example has served the purpose of giving an idea on how to add new elements into the existing xml document using LINQ.

Happy coding....

Reading XML values using LINQ

2011-10-20T07:43:00.000-07:00

Today i will be using examples to show the ways to read XML nodes and attributes value using LINQ. Everyone is aware of the powerful features LINQ provides, and the best thing about LINQ is simple and easy way to use it.

Step 1:-

I have created a customer.xml file, which contains the details about the customer. Ex:- Name, CompanyName, JobTitle etc.

<?xml version="1.0" encoding="utf-8" ?>

<Name>B. K. Mishra</Name>

<CompanyName>FIC Limited</CompanyName>

<JobTitle>Sales Representative</JobTitle>

<Address>1st Block, 19th cross,sector 7</Address>

<City>Bangalore</City>

<Country>India</Country>

<EmailId>B.k.mishra@fic.com</EmailId>

</Customer>

<Name>A. K. Mitra</Name>

<CompanyName>Sourcesoft Ltd</CompanyName>

<JobTitle>Maketing Manager</JobTitle>

<Address>Building no-10, second floor,1st block</Address>

<City>Delhi</City>

<Country>India</Country>

<EmailId>AKMitra@sourcesoft.com</EmailId>

</Customer>

<Name>S. Reddy</Name>

<CompanyName>Edge solution</CompanyName>

<JobTitle>Sales Representative</JobTitle>

<Address>Raheja arcade,3rd floor, sector 1</Address>

<City>Bangalore</City>

<Country>India</Country>

<EmailId>SReddy@EdgeSol.com</EmailId>

</Customer>

<Name>K. Manakotte</Name>

<JobTitle>Marketing Manager</JobTitle>

<Address>Citi tower, MG Road</Address>

<City>Bangalore</City>

<Country>India</Country>

<EmailId>k.manakotte@info.com</EmailId>

</Customer>

</Customers>

Step 2:

XDocument class represents a XML document. XDocument.Load method Creates a new System.Xml.Linq.XDocument object from a file.

(i) Following query will be used to retrieve all the customer details from the xml document

//retrieving all the customer details

var customerList =from cust in xDoc.Descendants("Customer")

select cust;

foreach (var cust in customerList)

{

//writing output to the console output window

Console.WriteLine(cust.Element("Name").Value + ";" +

cust.Element("CompanyName").Value+";"+cust.Element("JobTitle").Value

+ ";"+cust.Element("Fax").Value + ";" +cust.Element("EmailId").Value

);

}

Output

(ii) In this query anonymous class will be used to retrieve all the customer details from the xml document.

"Anonymous types typically are used in the select clause of a query expression to return a subset of the
properties from each object in the source sequence."

If we do not specify member names in the anonymous type, the compiler gives the

anonymous type members the same name as the property being used to initialize them.

Using Anonymous type, custom name can be assigned to the properties to select values.

var custList = from cust in xDoc.Descendants("Customer")

select new

{

CustomerName = cust.Element("Name").Value,

JobTitle = cust.Element("JobTitle").Value,

Fax = cust.Element("Fax").Value,

EmailId = cust.Element("EmailId").Value

};

foreach (var cust in custList)

{

Console.WriteLine(cust.CustomerName+";"+cust.JobTitle+";"+cust.Fax+";"+
cust.EmailId);

}

Output

(iii) Retrieving all the records where city=Bangalore

var blrCustomer = from custList in xDoc.Descendants("Customer")

where custList.Element("City").Value == "Bangalore"

select new

{

CustomerName = custList.Element("Name").Value,

JobTitle = custList.Element("JobTitle").Value,

Fax = custList.Element("Fax").Value,

EmailID = custList.Element("EmailId").Value

};

foreach (var cust in blrCustomer)

{

Console.WriteLine(cust.CustomerName + ";" + cust.JobTitle + ";" + cust.Fax + ";" +

cust.EmailID);

}

Output

(iv) Retrieving all the emailids from the xml document

var custEmailIDList = from custList in xDoc.Descendants("Customer")

select new {EmailID=custList.Element("EmailId").Value};

foreach (var email in custEmailIDList)

{

Console.WriteLine(email.EmailID);

}

Output

(v) Counting the length of character in name and then retrieving the customer records matching with the maximum value.

var custLength = from custList in xDoc.Descendants("Customer")

where custList.Element("Name").Value.Length==

( from n in xDoc.Descendants("Customer")

orderby n.Element("Name").Value.Length descending

select n.Element("Name").Value.Length).First()

select new

{

CustomerName = custList.Element("Name").Value,

JobTitle = custList.Element("JobTitle").Value,

Fax = custList.Element("Fax").Value,

EmailID = custList.Element("EmailId").Value

};

foreach (var cust in custLength)

{

Console.WriteLine(cust.CustomerName + ";" + cust.JobTitle + ";" + cust.Fax + ";" +

cust.EmailID);

}

Output

As you can see from the output that only those names, of which length is matching with the name of maximum length is displayed in the output.

I hope these examples gives clear idea about LINQ to XML features.

Happy Coding.....

Displaying Images as a thumbnail image in a DataView from Database in ASP.NET

2011-10-16T06:31:00.000-07:00

In this article i will be showing a example to retrieve image from Database and to display it as a thumbnail image in a dataview.

I have stored the image in a table named tblImage. SQL Server supports a datatype named as image for storing the image.

A brief description about image datatype is as follows:-

image : Variable-length binary data from 0 through 2^31-1 (2,147,483,647) bytes.

The following query can be used to create a table:

CREATE TABLE [dbo].[tblImage] (
[ID] [int] IDENTITY ,
[Image_Name] [varchar] (500) NULL ,
[Image] [image] NULL
)
In the create table statement, ID is declared as IDENTITY column.

Now I will be creating a simple Image Handler page using aspx page, that will be used to retrieve images from the database and write them to the Response Stream. The image ID will be passed as a QueryString to this image handler page, based on which the image byte array will be retrieved from database table and will be written to Response stream.

Step 1: ImageThumbnailCreation.aspx.cs

This class will work as a handler for processing the retrieved byte array from database and to write it as a Response stream.

public partial class ImageThumbnailCreation : System.Web.UI.Page

{

protected void Page_Load(object sender, EventArgs e)

{

if (Request.QueryString["ID"] != null) //tblImage ID column value

{

string strQuery = "select Image from tblImage where ID=@ID";

string strID = Request.QueryString["ID"];

//defining the connection string for the SqlConnection object

SqlConnection connection = new

SqlConnection(@"server=MyPC;database=master;uid=sa;pwd=password1");

//opening the connection
connection.Open();

SqlCommand cmd = new SqlCommand(strQuery);

//creating a parameter and binding it to the command object

cmd.Parameters.Add("@id", SqlDbType.Int).Value= Convert.ToInt32(strID);

cmd.CommandType = CommandType.Text;

cmd.Connection = connection;

//retrieving the byte array from command object

byte[] byteArray = (byte[])cmd.ExecuteScalar();

//Creating image from the retrieved byteArray

System.Drawing.Image image = System.Drawing.Image.FromStream(new

MemoryStream(byteArray));

//Creating the thumnailimage

System.Drawing.Image thumbImage = image.GetThumbnailImage(80,80, new

System.Drawing.Image.GetThumbnailImageAbort(ThumbnailCallback), IntPtr.Zero);

// memory stream object to store image bytes

MemoryStream imgStream = new MemoryStream();

// storing image into the memory stream

thumbImage.Save(imgStream, System.Drawing.Imaging.ImageFormat.Jpeg);

// byte array declaration as the same size of the image

byte[] byteImage = new Byte[imgStream.Length];

// resetting the memory stream

imgStream.Position = 0;

// load the byte array with the image

imgStream.Read(byteImage, 0, (int)imgStream.Length);

// return byteImage to caller with image type

Response.ContentType = "image/jpeg";

Response.BinaryWrite(byteImage);

}

public bool ThumbnailCallback()

{

return true;

}

Step 2: Using Template Field with Image Control on GridView (ShowingImageinGridView.aspx)

The GridView, contains the following columns:

a) ID column as BoundField

b) Image Name column as BoundField

c) Image column as a TemplateField with a Image control

It can be seen that the Image control ImageUrl property is referring to the respective handler page (ImageThumbnailCreation.aspx) and ID using the Eval statement.

<asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="False" RowStyle-Width="100%">

<asp:BoundField HeaderText="ID" DataField="ID" />

<asp:BoundField HeaderText="Image Name" DataField="Image_Name" />

<asp:TemplateField HeaderText="Image">

<asp:Image ID="Image1" runat="server" ImageUrl='<%# "ImageThumbnailCreation.aspx?ID=" +

Eval("ID")%>'/>

</ItemTemplate>

</asp:TemplateField>

</Columns>

</asp:GridView>

In the code behind of ShowingImageinGridView.aspx, following code is used to retrieve the image byte array from database and binding it to the GridView control.

void RetrieveAndBindImage()

{

//defining the connection string for the SqlConnection object

SqlConnection connection = new

SqlConnection(@"server=MyPC;database=master;uid=sa;pwd=password1");

try

{

//opening the connection

connection.Open();

SqlCommand cmd = new SqlCommand();

//select statement creation as a commandText

cmd.CommandText = "Select * from tblImage";

cmd.Connection = connection;

DataSet ds = new DataSet();

SqlDataAdapter da = new SqlDataAdapter(cmd);

da.Fill(ds);

GridView1.DataSource = ds;

GridView1.DataBind();

}

catch (Exception ex)

{ }

finally

{

if (connection != null)

connection.Close();

}

Following figure below displays the GridView with the thumbnail images from database:

Using this article one can create and show thumbnail images on the GridView control in aspx page.

Happy Coding....

Retrieving Image from SQL server database

2011-10-11T10:55:00.001-07:00

In this example i will be showing a example to retrieve stored image from the SQL Server database.

This example is suitable only to the scenario where we need to retrieve a single image in one call.

As i have shown in the previous example that i stored the image in a table named tblImage. I am copying the same create table statement from my previous example for better understanding.

SQL Server supports a datatype named as image for storing the image. A brief description about image datatype is as follows:-

image : Variable-length binary data from 0 through 2^31-1 (2,147,483,647) bytes.

The following query can be used to create a table:

CREATE TABLE [dbo].[tblImage] (

[ID] [int] IDENTITY ,

[Image_Name] [varchar] (500) NULL ,

[Image] [image] NULL

)

In the create table statement, ID is declared as IDENTITY column.

I created a sample page with a Image control and a button (Button Text - Retrieve Image). OnClick of "Retrieve Image" button, the image will be displayed/loaded in the Image box.

Following c# code will be used to retrieve image from the database table:

//defining the connection string for the SqlConnection object

SqlConnection connection = new SqlConnection(@"server=MyPC;database=master;uid=sa;pwd=password1");

try

{

//opening the database connection

connection.Open();

SqlCommand cmd = new SqlCommand();

//select statement creation as a commandText

cmd.CommandText = "Select Image from tblImage where ID=1";

cmd.Connection = connection;

//executing the query to retrive the byte array

// the retrieved binary data should be converted to byte array type

byte[] byteArray = (byte[])cmd.ExecuteScalar();

//The project structure contains a folder called TempImages

// which will be used to create and store image files

string path = Server.MapPath("TempImages");

//Using the FileStream class creating a jpeg file from byteArray

FileStream fs = new

FileStream(path+"\\"+Session.SessionID+".jpeg",FileMode.CreateNew,FileAccess.Write);

fs.Write(byteArray,0,byteArray.Length);

//Clears buffer for this stream and causes any buffered data to be written to the disc

fs.Flush();

//Closing the FileStream

fs.Close();

//Setting the ImageUrl to the image file path

Image1.ImageUrl = "\\TempImages\\"+Session.SessionID+".jpeg";

}

finally

{

if(connection!=null)

connection.Close();

}

It is always better to use Session.SessionID for maintaining the uniqueness of any id.

Later i will be showing another example of retrieving multiple images in one database call and binding it to the grid control.

Happy coding....

Image insertion in table of SQL Server database

2011-10-09T05:26:00.000-07:00

Herein i will demonstrate a way to insert image into a table of SQL Server database. Normally we come around a scenario where in we want to store images into database tables. As we know image cannot be directly stored/inserted into a database table. First the image should be converted into byte array and byte array can be inserted into database. I will be showing a detailed example to achieve the same objective.

I created a sample web page with the following controls:-

1) asp:FileUpload control for the browse functionality.

2) asp:Button, onclick of which the image will be saved into database table.

Now we need a table which can be used to store the selected images.

SQL Server supports a datatype named as image for storing the image. A brief description about image datatype is as follows:-

image : Variable-length binary data from 0 through 2^31-1 (2,147,483,647) bytes.

The following query can be used to create a table:

CREATE TABLE [dbo].[tblImage] (

[ID] [int] IDENTITY ,

[Image_Name] [varchar] (500) NULL ,

[Image] [image] NULL

)

In the create table statement, ID is declared as IDENTITY column.

On the OnClick event of Submit button, following code is written to retrieve the details of the image selected and then to save it in SQL Server table:

// Gets the length of the file.

//imgUploader is the ID of asp:FileUpload control

int len = imgUploader.PostedFile.ContentLength;

byte[] byteArray = new byte[len];

//reads a sequence of bytes from the current stream into the byteArray variable

imgUploader.PostedFile.InputStream.Read(byteArray, 0, len);

//retrieving the fileName which is selected using the FileUpload control

string strFileName = imgUploader.FileName;

//defining the connection string to connect to local database

SqlConnection connection = new SqlConnection(@"server=MyPC;database=master;uid=sa;pwd=password1");

try

{

//opening the connection

connection.Open();

SqlCommand cmd = new SqlCommand();

//insert statement creation as a commandText

cmd.CommandText = "INSERT INTO tblImage(Image_Name,Image) values(@Image_Name,@Image)";

cmd.Connection = connection;

cmd.Parameters.Add("@Image_Name", System.Data.SqlDbType.VarChar, 50);

cmd.Parameters.Add("@Image", System.Data.SqlDbType.Image);

cmd.Parameters["@Image_Name"].Value = strFileName;

cmd.Parameters["@Image"].Value = byteArray;

//executing the query

int result = cmd.ExecuteNonQuery();

if (result > 0)

Response.Write("Save Successful");

}

finally

{
//Closing the database connection

connection.Close();

}

In this example exceptions are not handled as this code is written for sample application but actual application should contain exception blocks.

I hope the given example can help people understand the way to store images in SQL Server table. There are other ways also in .Net which i will discuss later.

Happy Coding....

Subqueries in LINQ

2011-10-08T07:23:00.000-07:00

Definition:- In Linq, subquery is a query which can be contained within another query's
lambda expression.

The following example can help in understanding the subquery concept in Linq.

Examples:-

I will be using the four different ways to achieve the same output to showcase the flexibility and richness of LINQ.

In the following examples the query will return all the string values from the array whose length matches with the length of shortest string.

Option 1:-

string[] inSequence = { "london", "new york", "sydney", "new delhi" };

var outSequence = inSequence.Where(n => n.Length ==

inSequence.OrderBy(n2 =>n2.Length).Select(n2 => n2.Length).First());

foreach (string strTemp in outSequence)

Console.WriteLine(strTemp);

Output
-------
london
sydney

Option 2:-

string[] inSequence = { "london", "new york", "sydney", "new delhi" };

var outSequence= from n in inSequence

where n.Length == (from n2 in inSequence

orderby n2.Length

select n2.Length).First()

select n;

foreach (string strTemp in outputSequence1)

Console.WriteLine(strTemp);

Output
-------
london
sydney

Option 3:-

string[] inSequence = { "london", "new york", "sydney", "new delhi" };

var outSequence = from n in inSequence

where n.Length == inSequence.OrderBy(n2=>n2.Length).First().Length

select n;

foreach (string strTemp in outSequence)

Console.WriteLine(strTemp);

Output
-------
london
sydney

Option 4:-

string[] inSequence = { "london", "new york", "sydney", "new delhi" };

var outSequence = from n in inSequence

where n.Length == inSequence.Min().Length

select n;

foreach (string strTemp in outSequence)

Console.WriteLine(strTemp);

Output
-------
london
sydney

As it can be seen from the above examples, the same output has been achieved using four different query patterns.

This is the richness of LINQ, that a requirement can be fulfilled using different ways and purely depends on individuals, which path or way they want to take for achieving theirs goals.

Happy Coding...........

Building complex queries using LINQ

2011-10-06T09:12:00.000-07:00

The most important things to be remembered for this example are:-

1) All types are defined in System.Linq and System.Linq.Expressions namespaces.
2) A query operator never modifies/alters the input sequence, instead it always returns a
new sequence.
3) In a query expression data always flows from left to right through the sequence of
operators.(will be explaining this in the example)

In the given example multiple query operators (Where, OrderBy and Select) will be used in a query expression to build complex query.

At first a brief description about the Where, OrderBy and Select query operators is necessary, to give an insight view to what we are dealing with.

Where - The Where operator filters a sequence based on a predicate.When the object
returned by Where is enumerated, it enumerates the source sequence and yields
those elements for which the predicate function returns true.

OrderBy - OrderBy operator order a sequence according to one or more keys.

Select - The Select operator performs a projection over a sequence.When the object
returned by Select is enumerated, it enumerates the source sequence and yields the
results of evaluating the selector function for each element.

Complex query Example :-

string[] strInputSequence = { "london", "new york", "sydney", "new delhi" };
var outputSequence = strInputSequence

.Where(n => n.Length>5 && n.Contains("ne")) // filteration

.OrderBy(n => n) //sorting

.Select(n => n.ToUpper()); //upper case conversion

foreach (string name in outputSequence)

{

Console.WriteLine(name);

}

Output

-------------

NEW DELHI

NEW YORK

SYDNEY

In the above example Where operator returns a filtered version of the input sequence, which becomes a input to the OrderBy operator. The OrderBy operator returns sorted version of its input sequence which becomes a input sequence to the Select operator. And finally Select operator returns a sequence where each element is converted into upper case using the lambda expression.

The same desired result can be achieved by breaking the single complex query into separate queries for better understanding.

string[] strInputSequence = { "london", "new york", "sydney", "new delhi" };

var collfilter = strInputSequence.Where(n => n.Length > 5 && n.Contains("ne"));

foreach (string n in collfilter)

{

Console.WriteLine(n);

}

Output

---------

new york

sydney

new delhi

var collOrderby = collfilter.OrderBy(n => n);

foreach (string n in collOrderby)

{

Console.WriteLine(n);

}

Output

----------

new delhi

new york

sydney

var finalOutput = collOrderby.Select(n => n.ToUpper());

foreach (string n in finalOutput)

{

Console.WriteLine(n);

}

Output

------------

NEW DELHI

NEW YORK

SYDNEY

By using the above individual queries it can be easily understood that when the operators are chained in a query then the output sequence of one operator is the input sequence of another operator.

[ Following link can be referred to get in depth knowledge of query operators
http://msdn.microsoft.com/en-us/library/bb394939.aspx ]

Happy coding......

Deferred Execution or Lazy Execution in LINQ

2011-10-04T03:37:00.000-07:00

MSDN definition:

Deferred execution means that the evaluation of an expression is delayed until its realized value is actually required. Deferred execution can greatly improve performance when you have to manipulate large data collections, especially in programs that contain a series of chained queries or manipulations.

Most of the query operators in Linq executes not when they are constructed but when enumerated.

Following example can help in explaining the Deferred execution in LINQ queries:-

List<string> lNames= new List<string>();
lNames.Add("Steve");
IEnumerable<string> strLoop = lNames.Select(n => string.Concat("Hello " + n)); lNames.Add("Mark");
foreach (string n in strLoop)
{
Console.WriteLine(n);
}

Output of the query
-------------------
Hello Steve
Hello Mark

As it can be seen in the output of the query, the string “Mark” was added later after the construction of the query but still its included in the output. This is called as Deferred or Lazy execution.

Most of the query operators provides deferred execution mode except the following ones:-

a) operators that return a single element. Ex: Count etc.

b) Conversion operators. Ex: ToList, ToArray etc.

VS2010 Keyboard shortcuts

2011-10-03T03:35:00.000-07:00

I normally spent a long time in front of the computer using keyboard and mouse.And i am sure most of the Dot net developers will be using mouse to a great extent for doing day today activities. Obviously its true that we cannot avoid mouse fully by just using the keyboard shortcuts but it can really help in reducing the burden/pain of your fingers.

I am sure most of the people will be aware of the keyboard shortcuts of VS 2010. But still i wanted to share Microsoft link which can be used to download the keyboard shortcuts posters of VS2010.

The posters can be downloaded using the following link:-

http://www.microsoft.com/download/en/details.aspx?displaylang=en&id=13189

I am trying to be more dependent on keyboard shortcuts to a extent which can help me in reducing the dependency on the mouse.

Happy Coding......

Windows 8 - Pre-beta version for developers

2011-09-22T04:36:00.000-07:00

Windows 8 pre-beta version for developers is available for download on Microsoft website.

The installable can be downloaded using the following link:-

http://msdn.microsoft.com/en-us/windows/apps/br229516

Hopefully Windows 8 will be as successful as Windows XP is.

New features in the .NET Framework 4.5 Developer Preview

2011-09-22T04:29:00.000-07:00

I was going through Microsoft MSDN website and found that .Net Framework 4.5 developer preview is available as BETA version.

Following are some of the features available in .Net Framework 4.5:-

Web:

• Support for new HTML5 form types.
• Support for model binders in Web Forms. These let you bind data
controls directly to data-access methods, and automatically
convert user input to and from .NET Framework data types.
• Improved handling of client script through bundling and
minification for improved page performance.
• Support for reading and writing HTTP requests and responses
asynchronously.
• Support for asynchronous modules and handlers.

WPF:

• The new Ribbon control, which enables you to implement a ribbon
user interface that hosts a Quick Access Toolbar, Application
Menu, and tabs.
• The new INotifyDataErrorInfo, which supports synchronous and
asynchronous data validation.
• Improved performance when displaying large sets of grouped
data, and by accessing collections on non-UI threads.
• Repositioning of data as the values change (live shaping).
• Better integration between WPF and Win32 user interface
components.
• Ability to set the amount of time that should elapse between
property changes and data source updates.

WCF:

• Simplification of generated configuration files.
• Support for contract-first development.
• Ability to configure ASP.NET compatibility mode more easily.
• Changes in default transport property values to reduce the
likelihood that you will have to set them.
• Validation of WCF configuration files by Visual Studio as part
of the build process, so you can detect configuration errors
before you run your application.
• New HTTPS protocol mapping to make it easier to expose an
endpoint over HTTPS with Internet Information Services (IIS).
• Ability to generate metadata in a single WSDL document by
appending ?singleWSDL to the service URL.
• Support for configuring services in code.
• XML Editor tooltips.

The description of these added features are not provided on the website. After installation and usage of new beta version of VS 2011 will give a idea about these new features.

Converting xml document data into a table rowset view in SQL server

2011-09-21T04:13:00.001-07:00

OPENXML:-

OPENXML provides a rowset view over an XML document.

Syntax

OPENXML(idoc int [in],rowpattern nvarchar[in],[flags byte[in]])
[WITH (SchemaDeclaration | TableName)]

sp_xml_preparedocument:-

Reads the XML text provided as input, parses the text by using the MSXML parser (Msxmlsql.dll), and provides the parsed document in a state ready for consumption. sp_xml_preparedocument limits the number of elements that can be open at one time to 256.

Syntax

sp_xml_preparedocument

hdoc

OUTPUT

[ , xmltext ]

[ , xpath_namespaces ]

This example creates an internal representation of the XML image using sp_xml_preparedocument. A SELECT statement using an OPENXML rowset provider is then executed against the internal representation of the XML document.

DECLARE @BookDetails xml

DECLARE @handle INT

SET @BookDetails =

'<Books>

<Book>

<author_id>1</author_id>

<author_fname>Stephen</author_fname>

<author_lname>Smith</author_lname>

<book_title>Dotnet reference</book_title>

</Book>

<Book>

<author_id>2</author_id>

<author_fname>John</author_fname>

<author_lname>Arthor</author_lname>

<book_title>Donet complete review</book_title>

</Book>

</Books>'

EXEC sp_xml_preparedocument @handle OUTPUT, @BookDetails

SELECT * FROM OPENXML (@handle, '/Books/Book', 2) WITH

(author_id VARCHAR(5),

author_fname NVARCHAR(500),

author_lname NVARCHAR(500),

book_title NVARCHAR(100),

price nvarchar(10)

)

Output:-
author_id author_fname author_lname book_title Price

1 Stephen Smith Dotnet reference 30.50$

2 John Arthor Donet complete review 35.50$

The OPENXML rowset provider creates a five-column rowset (author_id, author_fname, author_lname, book_title and price) from which the SELECT statement retrieves the all the necessary columns.

The flag value is set to 2 indicating attribute-centric mapping. Therefore, the XML attributes map to the columns in the rowset. The rowpattern specified as /Books/Book identifies the <Books> nodes to be processed.

If the same SELECT statement is executed with flags set to any value other than 2, indicating element-centric mapping, the values of author_id, author_fname, author_lname, book_title and price for both of the book records in the XML document are returned as NULL.

Table row generation based on two date difference

2011-09-20T04:17:00.000-07:00

Recently i faced a situation where i was supposed to generate a table records based on the difference of two date parameter values.

After searching a lot on internet, i came up with a solution to my problem using Common Table expression feature of SQL server.

MSDN definition states:-
A common table expression (CTE) can be thought of as a temporary result set that is defined within the execution scope of a
single SELECT, INSERT, UPDATE, DELETE, or CREATE VIEW statement. A CTE is similar to a derived table in that it is not stored as an object and lasts only for the duration of the query.
Unlike a derived table, a CTE can be self-referencing and
can be referenced multiple times in the same query.

The query example for generating the table:-

BEGIN
Declare @FromDate as DateTime
Declare @ToDate as DateTime
Set @FromDate = cast('09/01/2011' as datetime)
Set @ToDate = cast('09/15/2011' as datetime)

;With cteTemp as (
select 1 i, @FromDate As FromDate
Union All
select i+1, DateAdd(Day,i,@FromDate)
From cteTemp
Where DateAdd(Day,i,@FromDate)<=@ToDate
)
select * from cteTemp
END

Above mentioned query generates 15 records based on the difference between the date values. As Common table expression works in recursive way, same table name is used inside the query for looping purpose.

LINQ queries

2011-09-20T04:14:00.000-07:00

LINQ popularly known as Language Integrated Query. LINQ language is one of the major advancement in .Net framework and is used for writing type-safe queries over object collections. LINQ was introduced in C# 3.0 and Framework 3.5.

In simple terms a basic unit of data in LINQ are called as sequence and elements.
Following example can explain these terms:

string[] place = { "Bangalore", "Pune", "Mumbai" };

In the above example, place is a sequence,and Bangalore, Pune and Mumbai are elements.

In the System.Linq class, there are around 40 query operators which are implemented as static extension methods.A query operator accepts an input sequence and generates output sequence.

For example:- Where operator can be used to extract cities with at least four characters length

string[] place = { "Bangalore", "Pune", "Mumbai" };
IEnumerable filteredPlace = place.Where(n=> n.Length>=4);

Output:-
Bangalore
Mumbai