showing a hidden panel in OnTextChanged event[Answered] RSS

• • Reply
  anjaliagarwa...

  Member

  511 Points

  1274 Posts

  showing a hidden panel in OnTextChanged event

  Feb 03, 2021 11:25 PM|anjaliagarwal5@yahoo.com|LINK

  I want to show a hidden panel when a user tabs out of a text box. I want to do this asynchronously. I wrote the following code. In below code my <asp:Panel is on another part of the page. Its not right above the updatePanel. I just put the panel above my textbox code for simplicity.

  <form id="form1" runat="server" method="post">
          <asp:ScriptManager ID="ScriptManager1" runat="server"></asp:ScriptManager>
  
           <asp:Panel runat="server" ID="pnlTest" Visible="false">
              This is a test
  
          </asp:Panel>
           <asp:UpdatePanel ID="up1" runat="server">
             <ContentTemplate >
          <asp:TextBox ID="txtTest" runat="server" OnTextChanged="txtestChanged" AutoPostBack="true"></asp:TextBox>
                 </ContentTemplate>
                 <Triggers>
         <asp:AsyncPostBackTrigger ControlID ="txtTest" />
        </Triggers>
               </asp:UpdatePanel>
         
      </form>

  any help will be greatly appreciated.

• • Reply
  oned_gk

  All-Star

  52683 Points

  15720 Posts

  Re: showing a hidden panel in OnTextChanged event

  Feb 04, 2021 02:26 AM|oned_gk|LINK

  AFAIK, the textbox should be outside update panel, then the panel is inside update panel. The code similar when you are not using ajax.

  Programming to simplify, don't look for difficult way
  Suwandi - Non Graduate Programmer
• • Reply
  XuDong Peng

  Contributor

  2110 Points

  674 Posts

  Re: showing a hidden panel in OnTextChanged event

  Feb 04, 2021 02:44 AM|XuDong Peng|LINK

  Hi anjaliagarwal5,

  Async post back in web forms still proceeds the whole page life cycle as if it's a traditional post. the difference is only the updated content inside target update panel that will be sent in response.

  Therefore, it will not affect the content outside the UpdatePanel. If you need to achieve the requirements you mentioned, you need to change it to a full page postback ( PostBackTrigger ).

  Page:
  <form id="form1" runat="server" method="post">
          <asp:ScriptManager ID="ScriptManager1" runat="server"></asp:ScriptManager>
                  <asp:Panel runat="server" ID="pnlTest" Visible="false">
                      This is a test
                  </asp:Panel>
          <asp:UpdatePanel ID="up1" runat="server" >
              <ContentTemplate>
                  <asp:TextBox ID="txtTest" runat="server" OnTextChanged="txtestChanged" AutoPostBack="true"></asp:TextBox>
              </ContentTemplate>
              <Triggers>
                  <asp:PostBackTrigger ControlID="txtTest" />
              </Triggers>
          </asp:UpdatePanel>
      </form>
  
  Code behind:
   protected void txtestChanged(object sender, EventArgs e)
          {
              pnlTest.Visible = true;
          }

  Or put the panel in another UpdatePanel and use the update() function.

      <form id="form1" runat="server" method="post">
          <asp:ScriptManager ID="ScriptManager1" runat="server"></asp:ScriptManager>
          <asp:UpdatePanel runat="server" ID="upPanel" UpdateMode="Conditional">
              <ContentTemplate>
                  <asp:Panel runat="server" ID="pnlTest" Visible="false">
                      This is a test
                  </asp:Panel>
              </ContentTemplate>
          </asp:UpdatePanel>
          <asp:UpdatePanel ID="up1" runat="server" >
              <ContentTemplate>
                  <asp:TextBox ID="txtTest" runat="server" OnTextChanged="txtestChanged" AutoPostBack="true"></asp:TextBox>
              </ContentTemplate>
              <Triggers>
                  <asp:AsyncPostBackTrigger ControlID="txtTest" EventName="TextChanged" />
                  <%--<asp:PostBackTrigger ControlID="txtTest" />--%>
              </Triggers>
          </asp:UpdatePanel>
      </form>
  
  Code behind:
   protected void txtestChanged(object sender, EventArgs e)
          {
              pnlTest.Visible = true;
              upPanel.Update();
          }

  Best regards,

  Xudong Peng

  .NET forums are moving to a new home on Microsoft Q&A, we encourage you to go to Microsoft Q&A for .NET for posting new questions and get involved today.