asp.net ajax doesn't keep textarea values in async postback - asp.net

Question

I have a dialog popup with a textearea, two listboxes and one button. By selecting a value in the first listbox and pressing the button ">" the selected value is passed to the second listbox. This is done with asp.net ajax.
<td>
<div align="center">
<textarea style="height:50px; overflow:hidden;";rows="20"
cols="40"
id="editor1"
class="tinymce">
</textarea>
</div>
</td>
I put the 2 listboxes and the button between asp.net uploadpanel. Like this:
<td>
<asp:UpdatePanel runat="server" id="updatePanel1">
<ContentTemplate>
<table width="100%" align="left">
<tr>
<td colspan="5">
<hr align="left" style="width:95%" />
</td>
</tr>
<tr>
<td valign="top">
<cc1:SWCListBox
ID="SWCListBox1"
runat="server"
Width="100"
SelectionMode="Single"
CssClass="VW1">
</cc1:SWCListBox>
</td>
<td
valign="top"
width="50"
align="center">
<cc1:SWCButton
Text=" > "
ID="SWCBtnAddValue"
CssClass="VW1 VWButton"
runat="server"
ToolTip="Add to list"
OnClick="AddValue_Click"
CausesValidation="false"
/>
<td valign="top">
<cc1:SWCListBox
id="SWCListBox2"
CssClass="VW1"
runat="server"
Width="100"
SelectionMode="Single"
/>
</td>
</tr>
</table>
</ContentTemplate>
</asp:UpdatePanel>
The probles is that when I type something in the textarea and make an async postback the text typed fades.
How can I keep the textarea value within async postbacks?
thank you.

Answer 1

This problem is because you use UpdatePanel, and the textarea is not an asp.net control. You have two solutions.
1) Make it asp.net control by placing the run="server" (or)
2) Place the post back value manually as:
<div align="center">
<textarea style="height:50px; overflow:hidden;";rows="20"
cols="40"
id="editor1"
name="editor_1"
class="tinymce">
<asp:Literal runat="server" id="txtEditor1" />
</textarea>
</div>
and on code behind
txtEditor1.Text = Server.HtmlEncode(Request.Form["editor_1"].ToString());
(because you use UpdatePanel its important to use Literal to add this value and not use <%=%>, or else its throw an error.