Question

how to fill textbox in asp.net while i am typing in another text
.. changes in one textbox will affect in another textbox auto.. and without refreshing my page.

Answer 1

Ok, try this. You will need the AJAX Control Toolkit. So read the article Installing AJAX Control Toolkit 4 in Visual Studio 2010 to see how to install it in Visual Studio.

Then you need to add a ScriptManager to your ASPX page. You will need to add the following code:

<asp:ScriptManager ID="ScriptManager1" runat="server">
</asp:ScriptManager>

What you then need to do, is add an UpdatePanel to your page. Inside this update panel, you need to place the textbox. This means that only the controls inside the update panel will refresh, and not the whole page. To do this, add the following code:

<asp:UpdatePanel ID="UpdatePanel1" runat="server">
  <ContentTemplate>

     <!--Add your Textbox Control to update here: Textbox1-->
     <asp:TextBox ID="Textbox1" runat="server" ReadOnly="True"></asp:TextBox> 
     <asp:TextBox ID="Textbox2" runat="server" ReadOnly="True" ontextchanged="Textbox2_TextChanged"></asp:TextBox>                             

  </ContentTemplate>
    <Triggers>
       <!--This is the textbox you will be typing text into: TextBox2-->
       <asp:AsyncPostBackTrigger ControlID="Textbox2" EventName="TextChanged" />
    </Triggers>
</asp:UpdatePanel>

The Trigger tells your page which control on the form needs to initiate the postback. Now in your .cs file, you need to add the event handler for the Textbox2 TextChanged event. Add the following code:

protected void Textbox2_TextChanged(object sender, EventArgs e)
{
    // Set the text of textbox1 = textbox2
}

I hope that this helps.