Getting started with AJAX and C#

[querry]

Hi all I am new to AJAX. I am developing web application in ASP.NET C#. Please could any of you tell me how I am to go about using ajax for getting certain server values using the javascript. Please suggest articles that suite this scenario.

Many thanks.

[dmjpro]

Hi all I am new to AJAX. I am developing web application in ASP.NET C#. Please could any of you tell me how I am to go about using ajax for getting certain server values using the javascript. Please suggest articles that suite this scenario.

Many thanks.

Please try some code.
Then come here with your specific problem.
Best of luck with your try.

Kind regards,
Dmjpro.

[pbmods]

Heya, Querry.

Changed thread title to better describe the problem (did you know that threads whose titles contain phrases such as, 'help' actually get FEWER responses?).

Have a look at this tutorial.

[querry]

Hi dmjpro and pdmods,

For dmjpro:
I am using the ASP.NET AJAX free library http://www.asp.net/ ]. I have two update panels.
In one update panel 1 I have, a textbox and a button. In update pannel 2 I have a ASP:Table. with no rows and cells.

What I want to do....
I want to add a TableRow and a TableCell with certain text taken from the textbox in the Update Panel 1 to the Table when the button is clicked.

What problems I face....
I am able to add a table row and a table cell to the table with the text specified in the textbox, but when I try to add another tacle row and table cell with a different text the first one gets replaced. This of course happens because the dynamically created controls do not persist after the postback. But I am not posting back. So I was expecting those controls to persist. But this does not happen.

What can be done? Can this be done with javascript??

For pdmods:
Oh! thanks for changing the title.

Thanks a lot!!

Cheers.

[dmjpro]

I am using the ASP.NET AJAX free library http://www.asp.net/ ]. I have two update panels.
In one update panel 1 I have, a textbox and a button. In update pannel 2 I have a ASP:Table. with no rows and cells.

What I want to do....
I want to add a TableRow and a TableCell with certain text taken from the textbox in the Update Panel 1 to the Table when the button is clicked.

What problems I face....
I am able to add a table row and a table cell to the table with the text specified in the textbox, but when I try to add another tacle row and table cell with a different text the first one gets replaced. This of course happens because the dynamically created controls do not persist after the postback. But I am not posting back. So I was expecting those controls to persist. But this does not happen.

What can be done? Can this be done with javascript??
Cheers.

You know the basic thing AJAX?
AJAX=>Asynchronous Java Script and XML.
And you need to be very strong on Java Script and XML.

Kind regards,
Dmjpro.

[acoder]

What can be done? Can this be done with javascript??

Yes it can. Post your code so we can see the problem.

[querry]

Yes it can. Post your code so we can see the problem.

Sorry to be late....

Ok, I found out the solution but I am not sure that it is the right way to handle the problem. What I am doing is simple. I create a XML file at the first visit of the page in the Page load event after checking the IsPostback flag. If it is not a postback then I create a XML file. I save it to disk. In the event handler for the "Add Row" button I add the new controls to the table and make relevent tag entries for these controls in the XML file and save it. My XML file looks like this.

<Table ID="tblPage_1">
      <TR ID="tr_1">
        <TC ID="tc1_1" Text="1" />
        <TC ID="tc1_2" Text="1" />
        <TC ID="tc1_3" Text="1" />
        <TC ID="tc1_4" Text="1" />
      </TR>
      <TR ID="tr_2">
        <TC ID="tc2_1" Text="2" />
        <TC ID="tc2_2" Text="2" />
        <TC ID="tc2_3" Text="2" />
        <TC ID="tc2_4" Text="2" />
      </TR>
      <TR ID="tr_3">
        <TC ID="tc3_1" Text="3" />
        <TC ID="tc3_2" Text="3" />
        <TC ID="tc3_3" Text="3" />
        <TC ID="tc3_4" Text="3" />
      </TR>
      <TR ID="tr_4">
        <TC ID="tc4_1" Text="4" />
        <TC ID="tc4_2" Text="4" />
        <TC ID="tc4_3" Text="4" />
        <TC ID="tc4_4" Text="4" />
      </TR>
    </Table>

Then in the coming postbacks I read the xml file and recreate the controls again.

So this solves the problem. I am not sure whether this is the most efficient way to do this. I was thinking of using something like xml serialization.

The pseudo code looks like this...

page_init()
{
  if(IsPostback == true)
  {
     //recreate the controls from the XML file.
 }
}
 
page_Load
{
 if(IsPostback != true)
 {
  //create a empty xml file.
 }
}
 
button_click()
{
  //Create and add new controls.
 //open the XML file and add the elements/nodes representing the newly added controls.
}

Now I have a new problem. Remember I am new to AJAX and have not use it here before. I want the table cells' background color to change when they are clicked. I need to add javascript to do that. How will I do that??

Many thanks.

[acoder]

Glad you solved your problem.

Now I have a new problem. Remember I am new to AJAX and have not use it here before. I want the table cells' background color to change when they are clicked. I need to add javascript to do that. How will I do that??

Create a new thread for this - you won't need Ajax, just plain old DHTML. Boring, ain't it?

[querry]

Ok, let me explain more....

I am working on a web application which will be able to create forms. These forms will be stored in the XML form, in a database (MSSQL). Another web application will be able to access these XML forms and then recreate them from the XML files using the xsl files. To arrange the controls I need to place them in table cells. My xml forms will look something like this.

<form>
      <table id=...>
             <tr id=...>
                   <tc id=...>
                          <element id=......... type="Label" text="Some text" />
                    </tc>
                     <tc id=...>
                          <element id=......... type="TextBox" text="" />
                     </tc>
               </tr>
       </table>
</form>

To place a Element inside a table cell I need to give a illusion that the cell is selected. Thats why I need to color the background in a different color. But the dynamic controls that are placed in the forms should appear to be placed without a postback. This is where, i belive, I need AJAX. If you have any comments please tell them to me. I will be glad to know them.

Many thanks again.

P.S.

Create a new thread for this - you won't need Ajax, just plain old DHTML. Boring, ain't it?

Hope its not boring now :)

[acoder]

To change a table cell background colour, access the table cell (you could pass 'this' to a function) and set its style property:

tablecell.style.backgroundColor='#123456';