Prince2/DotNetLearner/HTML5

DotNetCor2.1 Api CORS (Enable Cross Origin request)

noreply@blogger.com (Unknown) — Wed, 07 Nov 2018 00:15:00 +0000

The cross origin request are sometimes dreadful. This needs to be addressed at the api level

In Dotnet Core 2.1 we can handle it elegantly.

1) Install NuGet package Microsoft.AspNetCore.Cors from NuGet Package Manager.
2) Call AddCors in Startup.ConfigureServices to add CORS services to the app's service container

public void ConfigureServices(IServiceCollection services) { services.AddCors( O => O.AddPolicy("MyPolicy" , builder =>
{
builder.AllowAnyOrigin()
.AllowAnyMethod()
.AllowAnyHeader();

}
));

}

3) My project is WebApi so i will use Enable CORS with CORS Middleware
approach.

public void Configure(IApplicationBuilder app, IHostingEnvironment env,
ILoggerFactory loggerFactory)

{ loggerFactory.AddConsole(); if (env.IsDevelopment()) { app.UseDeveloperExceptionPage(); } // Shows UseCors with CorsPolicyBuilder. app.UseCors("MyPolicy");
}

4) Add the attribute [EnableCors("MyPolicy")]
on the controller or on the method if you need to be more specific

Retreiving field value in XML using cross apply

noreply@blogger.com (Unknown) — Tue, 07 Nov 2017 04:20:00 +0000

1) First we will cast the field data in a table to type xml from type text

2) you need to use with operator if namespace is defined ;WITH XMLNAMESPACES(DEFAULT 'http://schemas.datacontract.org/2004/07/Psv.Domain.Models.PexaNoa')

3) consider ContentXML as

'<Name>

<First>Jacob</First>

<Last>Sebastian</Last>

</Name>'

Begin

SELECT ContentXML INTO #tab12
FROM
(Select
Cast(data as xml) AS ContentXML
from ABC
) a

;WITH XMLNAMESPACES(DEFAULT 'http://schemas.datacontract.org')

SELECT t.value('(./First)[1]','NVARCHAR(MAX)') as FirstName
FROM #tab12
Cross Apply ContentXML.nodes('/Name') x(t)

Drop table #tab12
End

How to get a nested td value in Jquery

noreply@blogger.com (Unknown) — Thu, 13 Oct 2016 23:09:00 +0000

I have a difficult task at hand to get the value of a "td" which is generated by Keno Grid and its really driving me crazy due to time constraint at client end. Following is the solution.

Main div has id which gave me hope

the mock structure is below

<div id="mainDiv">
<div>
<div class="div-class">
<table>
<thead>
<tr>
<td>
header1
</td>
<td>
header 2
</td>
</tr>

</thead>
</table>
</div>
</div>

<div class="k-grid-content">
<table border="1">
<tbody>
<tr>
<td role="gridcell">column1</td>
<td role="gridcell">column2</td>
</tr>
<tr>
<td role="gridcell">columnn3</td>
<td role="gridcell">column4</td>
</tr>
</tbody>
</table>

</div>

</div>
<script>
$('#mainDiv').on('click', '.div-class table tbody tr', function () {
var value= $(this).find("td:first-child").text();
});
</script>

1) First capture the click event of the div with id.
2) Access the div you require with class name "div-class".
3) Access the "table".
4) Access the "tbody"
5) Access the "tr"
then get the values you require. Our requirement was to have first column value.

How to access the MVC controller using Jquery to get things done.

noreply@blogger.com (Unknown) — Wed, 07 Sep 2016 05:00:00 +0000

I have to do a task using jquery and calling controller method. Following is the code to achieve it.

1) div click.
2) the value is take from the "td".
3) passed to the ajax method.
4) show result in another grid.

Jquery part

$('#mainDiv').on('click', '.child-class table tbody tr', function () {
var Code = $(this).find("td:first-child").text();
$.ajax({
type: "POST",
async: true,
datatype: "json",

url: "/Controller/Method",
data: { "Code": "" + Code + "" },

success: function (data) {

$("#ToolTipCode").text(data);
},
error: function (x) {

$("#ToolTipCode").text("Doesnot exist.");
}
});

});

MVC controller

[HttpPost]
public ActionResult Method(string Code)
{
// do your stuff
return Json(codeWithDescription);
}

SP 2013 Auto Hosted App Discontinued

noreply@blogger.com (Unknown) — Fri, 01 May 2015 09:21:00 +0000

Share Point 2013 App Model Auto Hosted App option was in Preview and it was discontinued on 30-June-2014,

Error: When you try to deploy AutoHosted App to your O365 it will give you following error
something went wrong error

Cause: Microsoft Announcement about AutoHosted App

Now you can covert the autohosted to Provider hosted app use the following MSDN link to convert your applications.

Solution:How to Convert AutoHosted App to ProviderHosted App

Starting the SharePoint Central Admin giving runtime Error

noreply@blogger.com (Unknown) — Fri, 24 Apr 2015 11:33:00 +0000

When Starting the Share point Central Administration I get Run-time Error.

Follow the steps below

1) Go to IIS
2) Expand the "Sites" folder and select "SharePoint Central Administration v4 " virtual directory
3) In the "Actions" section click Explore
4) The site physical folder will open and contains web.config file.
5) Open web.config file find the "CustomErrors" tag.
6) Set its mode attribute to mode="Remoteonly"
7) Refresh and Re-open the central Administration Site in browser
8) You will Get the following error now

Error: This operation can be performed only on a computer that is joined to a server farm by users who have permissions in SQL Server to read from the configuration database. To connect this server to the server farm, use the SharePoint Products Configuration Wizard, located on the Start menu in Microsoft SharePoint 2010 Products.

Cause: SQL Server for SharePoint services stopped due to restart of my machine

9) Now Open the Services.msc
10) Restart the "SQL Server(SHAREPOINT)" service
11) Also Enable and Restart the "SQL Server Agent (SHAREPOINT)"
12) Also Enable and Restart "SQL Server Browser"

PS: I hope this helps. Please drop your comments.

how to use requiredfield validator with dropdownlist

noreply@blogger.com (Unknown) — Tue, 14 Apr 2015 12:35:00 +0000

Here is how we can use requiredfieldvalidator with dropdownlist.

Set the below property of the dropdownlist control

AppendDataBoundItems = true

Then Insert a default value in the Page_Load event

ddl.Items.Insert(0, new ListItem("<<-Select-->", "-1"));

Now define the required field validator and set its initialvalue attribute to "-1"

<asp:RequiredFieldValidator ID="reqddl" runat="server" Text="*" ControlToValidate="ddlRole" InitialValue="-1" SetFocusOnError="true" Display="Dynamic" ValidationGroup="Add"></asp:RequiredFieldValidator>

Happy coding :)

Hide and Show div using Jquery

noreply@blogger.com (Unknown) — Mon, 02 Mar 2015 06:30:00 +0000

We have a requirement to hide and show our Grid in a div.

Following is the code to achieve this functionality

Define the first div which shows the caption Show/Hide. Whenever the mouse is over the div "divtoggle1" second div "divOrders" is either shown or hidden

The below <Div> is defined with caption Show/Hide

<div id="divtoggle1" style="text-align:left;width:250px">
Show/Hide
</div>

The below <Div> contains the GridView which we need to Show/Hide

<div id="divOrders">

<asp:GridView ID="grvOrders" runat="server" AutoGenerateColumns="False" >

<Columns>
<asp:TemplateField HeaderText="firstcolumn" >
<ItemTemplate>
<asp:LinkButton ID="lnkName" runat="server" Text='<%#
DataBinder.Eval(Container.DataItem,"Names") %>' CommandName="OrderDetail">
</asp:LinkButton>
</ItemTemplate>
</asp:TemplateField>
</Columns>
</asp:GridView>
</div>

The Jquery part which toggle the div

we are access the div "divtoggle" with "#" sign because in Jquery when you want to access any element by ID you have to use "#" sign before the name of element.

we call the "divtoggle1" mouseover event and in that event we are checking the second div "divOrders".

if "#divOrders" visible then hide it or if it is hidden then make it visible. we also added delay function to make the Show/Hide smooth and we used hide argument "slow".

<script type="text/javascript">
$(document).ready(function () {
$("#divtoggle1").mouseover(function () {

if ($('#divOrders').is(':visible')) {
$("#divOrders").delay(100).hide('slow');
$("#divtoggle1").text('Show Orders');
}
else {
$("#divOrders").delay(100).show('slow');
$("#divtoggle1").text('Hide Orders');
}

}); // end of mouse over
}); // end of ready function

</script>

Passing-parameter-value-through-a-function-from-anchor-tag-in-a-gridview

noreply@blogger.com (Unknown) — Mon, 02 Feb 2015 13:49:00 +0000

We have a requirement where we have to pass Session values and DataBound values to Javascript function using Anchor tag in Gridview.

Following is the Anchor defined in the Gridview where we are passing Session and Eval values as parameter to the Javascript function

OpenAttachmentWindow(roomId,StudentId,Id).

Javascript function description

<script language="javascript" type="text/javascript">

function OpenAttachmentWindow(roomId, StudentId, Id)
{
var ReadOnly = 0;

window.open('UploadSupplierAttachments.aspx?roomId=' + roomId + '&studentId=' +
StudentId + '&id=' + Id + '&ReadOnly=' + ReadOnly, '', 'width=700,height=500')

}

</script>

Gridview Template column

We have anchor html control which will pas the server side arguments to javascript function.

<asp:TemplateField HeaderText="view">

<a onclick='<%# "OpenAttachmentWindow(" +Session["roomId"] + " , " +
Session["StudentId"] + ", " + Eval("Id") +" );" %>' id="a1" runat="server" >Attachment </a>

</ItemTemplate>

</asp:TemplateField>

Compare Validator DataTypeCheck

noreply@blogger.com (Unknown) — Wed, 21 Jan 2015 06:15:00 +0000

I have been using asp.net Validator controls for quite long. I have come across the unexplored property of Compare Validator which can check input against following types

1) Currency

2) Date

3) Double

4) Integer

5) String

you can use the Validator by setting the following properties

Operator="DataTypeCheck"

Select any of the below types for data type check

Type= Currency

Date

Double

Integer

String

Example:

<asp:CompareValidator ID="CompareValidatorNumber" runat="server" ControlToValidate="txtTelephone" Text="*" Display="Dynamic" ErrorMessage="Please enter numbers only" Operator="DataTypeCheck" Type="String"></asp:CompareValidator>

filling DataSet by calling oracle stored procedure

noreply@blogger.com (Unknown) — Wed, 19 Nov 2014 10:18:00 +0000

Use the below code as a reference.

public void GetDatainDataset()
{

using (OracleConnection conn = new OracleConnection(strConnStr)) { conn.Open();

OracleCommand cmdABC = new OracleCommand();

  cmdABC.Connection = conn;

  cmdABC.CommandType = CommandType.StoredProcedure;

  cmdABC.CommandText = Stored Procedure Name;

  cmdABC.Parameters.Add("P_RC", OracleDbType.RefCursor).Direction   = ParameterDirection.Output;

DataSet ds = new DataSet();

OracleDataAdapter adapter = new OracleDataAdapter(cmdPlants);

adapter.Fill(ds);

ddlABC.DataSource = ds.Tables[0];

  ddlABC.DataTextField = "A";

  ddlABC.DataValueField = "B";

  ddlABC.DataBind();

conn.Close();

conn.Dispose();}

Gadget Enthusiasts pebble dropped price for original pebble and pebble steel

noreply@blogger.com (Unknown) — Mon, 20 Oct 2014 18:20:00 +0000

Statement

anxiously waiting for my pebble to connect it to my nexus 4

Generate c# code from *.wsdl file using WSDL Tool

noreply@blogger.com (Unknown) — Wed, 01 Oct 2014 11:10:00 +0000

Web Service Descriptor Language Tool

is used to generate the c# code from the *.wsdl file and you can use it as proxy class for prototyping

We have been assigned a small integration project. It is in inception stage so many things are not clear and we have been given one *.wsdl file to study and we tried to generate c# code from it to work on our application prototype

wsdl.exe can be found in Visual Studio 2005 at the following location

C:\Program Files\Microsoft Visual Studio 8\SDK\v2.0\Bin

you can use following command to generate the proxy class from command prompt

wsdl /out:C:\Test\out:myProxyClass.cs C:\Test\MyWsdlfile.wsdl

Now you can add the myProcyClass.cs in your project and use its methods. Please don't modify the myProcyClass.cs file as it auto generated.

SQL Query Column values as comma separated

noreply@blogger.com (Unknown) — Wed, 10 Sep 2014 14:28:00 +0000

Introduction

I have a table as shown below, which has Country_Code and Cities of the a country.

I need to retrieve distinct cities in a country based on the Country_Code
column as a comma separated string.

SQL Statement

The following SQL Statement shows how it can be achieved

Begin

declare @str varchar(1000)

SELECT @str= coalesce(@str + ',' , '') + a.CountryLang_Desc 
FROM (SELECT DISTINCT CountryLang_Desc from CountryLanguages where Country_Code='IN') a

print @str

End

_doPostBack and Browser back button behavior

noreply@blogger.com (Unknown) — Wed, 13 Aug 2014 13:21:00 +0000

The odd behavior of Browser Back Button on _doPostBack()

In one of application developed in Asp.net page is not behaving as desired when browser back button is pressed.

The steps performed in the following order

1) Go to the page
2) Click a link which causes _doPostBack and navigate to new page
3) Press the browser back button
4)click on any button

This will end up re-executing the _doPostBack() action instead of firing Button click event.

The reason or behavior is as follows

Back button goes back to the previous page - page is not reloaded from server!
Browser assigns __EVENTxxx etc. with the previous POST back values
The server detects the __EVENTxxxx form vars and routes events accordingly (incorrect behavior)

To overcome this behavior i had a simple solution in my mind to expire the page and empty the secure page cache.

It worked for me by introducing following code in page load event and use is at the top not in any checks like IsPostback etc.

Response.Cache.SetCacheability(HttpCacheability.NoCache);

Response.Cache.SetAllowResponseInBrowserHistory(false);

Disable Secure Page Cache or Expire Web Page on browser button

noreply@blogger.com (Unknown) — Wed, 16 Jul 2014 10:06:00 +0000

Expire Web Page on Browser Back/Forward Button click

Why we need to expire the web page when browser back/forward button
is clicked. It is one of the security concern that if any user using any
public shared computer and left the browsed page open the bad guy
can sneak peak in to your information by using browser back/ forward buttons.

There are lot of solution available but the solution is little tricky lets start

Part 1

First of all add following response properties in you Page_Load function
and don't put this code in if(!IsPostback) code block in Page_Load function
see sample code as below

protected void Page_Load(object sender, System.EventArgs e)
{
if (!Page.IsPostBack)
{
// you Logic here

}

Page.Response.Cache.SetCacheability(HttpCacheability.NoCache);
Page.Response.Cache.SetNoStore();
Page.Response.Cache.AppendCacheExtension("no-cache");
Page.Response.Expires = 0;

}

If there is any action or postback then the below mentioned lines will work and expire the page

Page.Response.Cache.SetCacheability(HttpCacheability.NoCache);
Page.Response.Cache.SetNoStore();
Page.Response.Cache.AppendCacheExtension("no-cache");
Page.Response.Expires = 0;

Part 2

Now to add your own logic to cater pages where we don't have any postback.

Add the following code in you Page_Load function if(!IsPostBack) check
as below

We have taken one Session variable "TimeStamp" and one ViewState variable "TimeStamp".
when the web page is loaded with any navigation link inside the application we have Session["TimeStamp"] and ViewState["TimeStamp"] variable value "null" and that means browser buttons are not clicked and we don't have to expire the Page.

Whenever the user click the browser back/forward button the ViewState will become null for that page and Session will contain the "TimeStamp" so we infer that browser button is clicked and we need to expire the page and redirect it to a page in our case we redirect to WebPageExpire.aspx .

protected void Page_Load(object sender, System.EventArgs e)
{
if (!Page.IsPostBack)
{
// you Logic here
  if (isPageExpired())
{
Response.Redirect("WebPageExpire.aspx");
}
else
{
string strNow = DateTime.Now.ToString();
Session["TimeStamp"] = strNow;
ViewState["TimeStamp"] = strNow;
}

}

Page.Response.Cache.SetCacheability(HttpCacheability.NoCache);
Page.Response.Cache.SetNoStore();
Page.Response.Cache.AppendCacheExtension("no-cache");
Page.Response.Expires = 0;

}

Now add the function isPageExpired() which compares the Session["TimeStamp"] and ViewState["TimeStamp"].

private bool isPageExpired()
{
  if (Session["TimeStamp"] == ViewState["TimeStamp"])
return false;
else
return true;

}

One more thing from where ever you are navigating either asp:Button , asp:Link etc
we have to initialize the Session["TimeStamp"]= null so that every time when we navigate legitimately our Session and Viewstate have same value.

    protected void BtnRegister_ServerClick(object sender, System.Web.UI.ImageClickEventArgs e)
{
Session["TimeStamp"] = null;
Response.Redirect("Register.aspx", false);
}

The same logic we have to add in every page where we need secure cache disable functionality plus you have to design a page in my case i have designed the page WebPageExpire.aspx and show message to user WebPage has expired please login again.

I hope this will solve the problem and looking forward to hear from you guys.

Microsoft Anti Cross Site Scripting Library a tool to defend yourself against Cross Site Scripting XSS

noreply@blogger.com (Unknown) — Mon, 19 May 2014 11:40:00 +0000

To prevent cross site scripting use Microsoft Anti Cross Site Scripting Library its free and need of time following is the link from where you can download.

Microsoft Anti Cross Site Scripting Library

Encrypt View State Data for ASP.net Application

noreply@blogger.com (Unknown) — Wed, 12 Feb 2014 11:22:00 +0000

Encrypting view state is used to reduce the chance of information disclosure and some one getting information to cause harm to the user.

In Asp.net 2.0 the support for encryption has been enhanced. Now you can define encryption of view state on Page level. Following is the implementation in the Page tag of the aspx file.

<%@ page language="c#" masterpagefile="~/MasterPage.master" inherits="Abc.Default, App_Web_Default.aspx.cdcab7d2" validaterequest="false" theme="ABC" viewstateencryptionmode="Always" enableEventValidation="false" %>

The attribute ViewStateEncryptionMode has three values.
1) Auto
2) Always
3) Never

The default for ViewStateEncryptionMode is Auto.

We can also set its value in the web.config file as

<system.web>

</system.web>

</configuration>

How to access a radio button selected Boundfield value from a GridView in javascript

noreply@blogger.com (Unknown) — Sun, 12 Jan 2014 12:26:00 +0000

function RefreshParent()
{
//get the gridview object
var gv = document.getElementById("grdViewBrand");
//get the gridview input object collection
var rbs = gv.getElementsByTagName("input");
//Traverse the input object collection
for (var i = 0; i < rbs.length; i++)
{
//Check for the checked radio button
if (rbs[i].type == "radio")
{
if (rbs[i].checked)
{
//get the bound field value from the position where check box is checked
// [i+1] is due to gridview dataBoundField includes header
row also which is not present in input collection
var brandName = gv.rows[i+1].cells[0].innerText;
break;
}
}
}

Description

Get the gridview object and its inputs elements.
Traverse through the (input)collection and get the
selected Radio Button row.

Now from the griview object get the rows position and the cell
and call its inner text property

Enforce Secure flag for session cookies in ASP.net

noreply@blogger.com (Unknown) — Tue, 31 Dec 2013 13:22:00 +0000

To avoid disclosure of sensitive information in transit from the server to the browser,
many applications use HTTP over SSL (HTTPS).
However, because it may be possible to navigate away from the HTTPS protected transport settings of the site,
either by someone specifically providing a link to a non https:// resource or via the application using a absolute reference and mistakenly using http://,
users may subject to their communications being "sniffed" between the browser and server.
Not only is the user data posted to a web server important to protect using HTTPS -
if an attacker were able to see session identifiers passing in plain sight they could reuse
them and masquerade as another user while the session was active (i.e. The user hadn't logged off).
To avoid this from happening, cookies can be set to be "secure" - that is,
they are only to be transmitted when a secure channel is available.

Add the following tag in the webConfig

<System.web>
<httpCookies requireSSL="true"/>
</System.web>

Autocomplete to work with Firefox,IE9+ and Chrome ASP.net C# (AutocompleteType does not produce desired results)

noreply@blogger.com (Unknown) — Wed, 11 Dec 2013 06:54:00 +0000

AutoCompleteType is not producing the desired results auto complete feature in the password field needs to be disabled which was done through following Asp.net attribute of < asp:TextBox >

< asp:TextBox ID="passcode" runat="server" size="20" TextMode="Password" AutoCompleteType="Disabled" Wrap="False" > < /asp:TextBox >

When it was tested it is not working with IE9 and chrome.
The quick fix for this potential security threat is as below
In the PageLoad event of your aspx.cs file add attribute as follows

passcode.Attributes.Add("autocomplete", "off");

WEB Workers (Part 2)

noreply@blogger.com (Unknown) — Tue, 12 Feb 2013 12:44:00 +0000

Below is the simple code to see WEB Workers in action

The Main file code
<!DOCTYPE html>
<html>
<body>
<p>Count numbers: <output id="result"></output></p>
<button onclick="startWorker()">Start Worker</button>
<button onclick="stopWorker()">Stop Worker</button>

<script>
var w;
function startWorker()
{
if(typeof(Worker)!=="undefined")
{
if(typeof(w)=="undefined")
{
w=new Worker("demo_workers.js");
}
w.onmessage = function (event) {
document.getElementById("result").innerHTML=event.data;
};
}
else
{
document.getElementById("result").innerHTML="Sorry, your browser does not support Web Workers...";
}
}
function stopWorker()
{
w.terminate();
}
</script>

</body>
</html>

The js file code

function showMessage()
{
postMessage("Hello World.");
}

Web Workers (Run Locally)

noreply@blogger.com (Unknown) — Sun, 10 Feb 2013 09:51:00 +0000

How to run WEB Worker locally with Google Chrome.

IE version 10 supports WEB Workers the previous versions doesnot support.

I face this problem while creating and testing WEB Workers object on my local machine and nothing was happening. In order to run the code on your local machine with Google chrome we have to enable the flag via parameters while running the code

Right click on the browser icon and select properties there a window will appear and you will see Target field. Use following command and append it in the Target field while running Chrome. Please make sure to close all Chrome windows.

--allow-file-access-from-files
The Target field Look something like following C:\Users\UserNameHere\AppData\Local\Google\Chrome\Application\chrome.exe" --allow-file-access-from-files

Note: this is risky way of running and testing your code.
Please deploy your code on webserver and you dont need to
make these changes.
Please be aware to remove the above changes from browser.

HTML5 WEB Workers Part 1

noreply@blogger.com (Unknown) — Sat, 09 Feb 2013 11:55:00 +0000

Javascript is designed to run in single Thread environment.

Javascript does not support Multi Threading. Javascript is single threaded and this is major hindrance in implementing some cool capabilities in applications.There are other workarounds used by developers but they dont provide the flexibility which is now available with introduction of WEB Workers in HTML5.

WEB Workers are perfect for keeping your UI refresh, performant and responsive for users.

Types of WEB Workers

Dedicated Workers
Shared Workers

Note: Only Dedicated Workers are discussed in this article

WEB Worker and DOM

Since WEB worker are external files they don't have access to following Javascript objects.

The window object
The document object
The parent object

Continued Part 2

CANVAS 2D API (HTML5 CANVAS Part 3)

noreply@blogger.com (Unknown) — Wed, 06 Feb 2013 07:17:00 +0000

Drawing on canvas can be done by canvas 2D API
There are plethora of Methods and Properties in canvas 2D API.

2D API reference:click