AJAX control doesn't seem to do partial page update.

Question

User-753400859 posted

I'm trying to do a very simple partial page update with a TextBox control using the TextChanged event to fire the update.  Everything works, except its doing a full page post pack rather than a partial page update.  I don't want the entire page to post back, what can I do to make this work.  Here is the code in question:

 

 

<asp:UpdatePanel ID="usernamePanel" UpdateMode="Conditional" ChildrenAsTriggers="true" runat="server">
           <Triggers>
d                             <asp:AsyncPostBackTrigger EventName="TextChanged" ControlID="username" />
                                    </Triggers>
                                    <ContentTemplate>                                                   
                                        <asp:PlaceHolder ID="notUniqueUsername" runat="Server" Visible="false"><font color="red">Username already in use.   Please select another one.</font></asp:PlaceHolder>
                                                
									    <asp:ValidationSummary ID="Validationsummary2" Runat="server" ShowSummary="true" DisplayMode="BulletList"
										HeaderText="b>" />
								
								</ContentTemplate>
                                  </asp:UpdatePanel>

<asp:TextBox width="300" MaxLength="25" ID="username" AutoPostBack="true" TextMode="SingleLine" Runat="server" />								

  

<asp:UpdatePanel id="<span" class="st"><Triggers><ContentTemplate><asp:TextBox width="<span" class="st"></asp:TextBox></ContentTemplate></Triggers></asp:UpdatePanel>

Answer 1

User-1684099974 posted

Place the textbox inside of the updatepanel's contenttemplate.  If a control which causes postback is not in an updatepanel, it's going to cause a visible refresh.  Adding it as a trigger to an updatepanel does nothing to stop that.  It's the updatepanel itself that hides the refresh, not being a trigger.

Answer 2

User-753400859 posted

 Even if I stick the code in the updatepanel, I still get a full page refresh.  Checking scriptmanager1.IsAsyncPostBack shows false.

  

<asp:UpdatePanel ID="usernamePanel" UpdateMode="Always" runat="server">										
										<Triggers>
										    <asp:AsyncPostBackTrigger ControlID="username" EventName="TextChanged" />
										</Triggers>
                                        <ContentTemplate>                                                   
                                            <asp:TextBox width="300" MaxLength="25" OnTextChanged="usernameCheck" ID="username" TextMode="SingleLine" Runat="server" />				                                            
                                            <asp:PlaceHolder ID="notUniqueUsername" runat="Server" Visible="false"><font color="red">Username already in use.</font></asp:PlaceHolder>												
										</ContentTemplate>
										</asp:UpdatePanel>

 
 

Answer 3

User770037084 posted

If a control which causes postback is not in an updatepanel, it's going to cause a visible refresh.  Adding it as a trigger to an updatepanel does nothing to stop that.  It's the updatepanel itself that hides the refresh, not being a trigger.

 

AsyncPostBackTriggers don't have to be inside an UpdatePanel.  Try this code, for example:

<asp:ScriptManager runat="server" ID="sm1" />
<asp:Button runat="server" ID="Button1" OnClick="Button1_Click" />
<asp:UpdatePanel runat="server" ID="up1">
  <Triggers>
    <asp:AsyncPostBackTrigger ControlID="Button1" />
  </Triggers>
  <ContentTemplate>
    <asp:Literal runat="server" ID="Literal1" />
  </ContentTemplate>
</asp:UpdatePanel>

protected void Button1_Click(object sender, EventArgs e)
{
  Literal1.Text = DateTime.Now.ToString();
}

Clicking Button1 results in a partial postback, not a full one.

Answer 4

User770037084 posted

I'm trying to do a very simple partial page update with a TextBox control using the TextChanged event to fire the update.  Everything works, except its doing a full page post pack rather than a partial page update.  I don't want the entire page to post back, what can I do to make this work.  Here is the code in question:

 

Try removing the EventName qualifier on your AsyncPostBackTrigger declaration.

Answer 5

User-1623675128 posted

Where is your ScriptManager TAG in your code????

 

Thanks,

Answer 6

User-753400859 posted

 The script manager tag is in there, just not in the sample code that I posted.  Its near the top of the page after the form tag.

 I think what I need to do it create a plain-jane page and then try the samples that are posted all over the place.  That way I can confirm that it actually works.  (I tried upgrading my existing .NET app to use ajax.)