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                                                                                                                          Nothing shocks me, I am a Software Engineer.

Archive for March, 2009

Update Panel, Default Button and FireFox

Posted by Virendra Dugar on March 29, 2009

ASP.Net 2.0 comes up with a new concept called “Default Button” which is one button on the form will work as default button. Whenever we press the enter button default button will be called.

As for example: In a text box after typing you press enter your default button’s event will be fired.

However, the one thing that was bothering me with the Default Button is it worked like a charm in IE. In Firefox, it behaved weirdly. The problem wasn’t that it didn’t do a postback. That it did. What it didn’t do was hit the server side event (the button click event).

When you are selected in any textbox and you press enter, IE will submit this and hit the button click even. However with FireFox, it will only submit – not call the onclick event.

To solve this add: UseSubmitBehavior="False" to your submit button. Now you can press enter whenever you want in your form and it will do the proper submit regardless of IE or Firefox.

Enjoy….

Posted in Ajax, ASP.NET | Tagged: , | 4 Comments »

showModalDialog and postbacks in ASP.NET

Posted by Virendra Dugar on March 23, 2009

I learned something new today that when window.showModalDialog is used to open a modal window on the client from parent page using  javascript. And whenever postback occurs in the modal window, it would open up a new window.  A normal window.open works fine, this is the problem only with modal window.

Finally I found a solution which is very simple by just including the below tag in the <head> section of the modal Window.

<base target="_self"/>

 And also we need to set the output cache property to “1” otherwise next time when you try to open the modal window, it will take it from cache.

<% @ OutputCache Duration="1" VaryByParam="none"%>

Enjoy..

Posted in ASP.NET, JavaScript | Tagged: , | 4 Comments »

Visual studio keyboard shortcuts

Posted by Virendra Dugar on March 10, 2009

Download the cool PDF versions of all the keyboard shortcut available in Visual Studio 2005 and 2008.

For C#
For VB.NET

Make habit of using shortcut keys and save your time. 🙂

Enjoy…

Posted in ASP.NET, C#, VB.NET | Tagged: , , | Leave a Comment »

ASP.NET Page Life Cycle Overview

Posted by Virendra Dugar on March 6, 2009

I found some good articles of ASP.NET Page Life Cycle. Check it out.

http://msdn.microsoft.com/en-us/library/ms178472.aspx

http://www.techinterviews.com/?p=176

http://www.sql-server-performance.com/articles/asp_ado/page_life_cycle_p1.aspx

There is a diagram of the page life cycle events available on these sites

http://www.eggheadcafe.com/articles/20051227.asp

http://spazzarama.wordpress.com/2009/02/04/aspnet-lifecycle/

Enojy…

Posted in ASP.NET | Tagged: | Leave a Comment »

ViewState and Readonly Property of text box.

Posted by Virendra Dugar on March 1, 2009

Well, this has been under discussion for some time that ASP.Net TextBox which has the Readonly property assigned true not retaining the server side or client side changes. The changes are getting ignored across postbacks.  

Let’s understand both the scenario

When EnableViewState is true

When EnableViewState is set to true, then readonly textbox does maintain the server side changes but it does not maintain client side changes.

Let us understand with an example 

Declare a readonly text box and two buttons

 

Put this javascript function in the head section which modifies the text box value on the client side.

In the page load section, set the text box value.

On button click, just display the value of text box using Response.write().

Now, Just execute this program.

Initially text box is having “Read only text box” . Now click on the Client Side button and you will see that text box value is changed to “Modified sample Text”. Now click on server side button. You will see the Server side value assigned to the text box is displayed on the screen not the client side value.

When EnableViewState is False

When EnableViewState is set to false, then readonly textbox does not maintain the server side changes and client side changes.

Let us understand with an example

Declare a readonly text box with EnableViewState= false and two buttons.

Put this javascript function in the head section which modifies the text box value on the client side.

In the page load section,set the text box value.

On button click, just display the value of text box using Response.write().

Now, Just execute this program.

 Initially text box is having “Read only text box” . Now click on the Client Side button and you will see that text box value is changed to “Modified sample Text”. Now click on server side button. You will see that nothing is displayed on the screen. Textbox loses not only the client side value but also the server side value assigned to it. 

The interesting thing is if you assign any value to the readonly text box with enableviewstate = false at design time, it maintains that value.

 For example,

Textbox3 maintains it’s value assigned at design time.

Now, the question over here is that is there any way to retrieve the value from the server once it’s lost. Yes there is..

Request.Form[TextBox2.UniqueID], This line will give the last modified (Whether on server or on client) value of text box.

As we saw,there are number of concerns while using the readonly property. The best solution to avoid all these issues is in the code behind file, within the Page_Load add the following line of code:-

Now you will notice that when you run the page, the client side changes you make in the TextBox (via the Javascript) is retained across postback.

Check out these other reference :

http://west-wind.com/weblog/posts/3939.aspx

http://www.g9th.com/blog/post/2006/12/Readonly-property-of-Textbox-in-ASPNET.aspx

Enjoy…..

Posted in ASP.NET | Tagged: | 8 Comments »

 
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