troubleshooting Question

Why is the asp:UpdatePanel not changing the value of my ASP:Textbox when the textbox is updated from Codebehind?

Avatar of Je Vught
Je VughtFlag for United States of America asked on
JavaScript.NET ProgrammingC#ASP.NETAJAX
5 Comments1 Solution22 ViewsLast Modified:

My scheme:

  • I have a label along with a number of textboxes loaded inside an asp:Updatepanel. These controls are initially loaded with values from an SQL database. These values are based on the initial index passed to the page.
  • Additionally the page contains a gridview which contains a list of "contacts".
  • The idea is that if the user selects a contact from the gridview, the index is used to re-query the SQL db. This function returns a datatable which is used to populate the above mentioned textboxes with the selected contacts data - name, address, emails, etc. The user can then modify the textboxes as necessary.
  • At present, I'm using a asp:timer to trigger the updatepanel when a different contact is selected (though I'd welcome a more elegant trigger solution).


When the page is first loaded, the label and all the textbox controls are populated without issue.


The problem: When subsequent contacts are selected, ONLY the label value changes - NOT the textbox values.

What I've tried:

  • If I disable the timer/trigger, then even the label is not updated when a record is selected in the gridview. This seems to indicate that the timer/trigger is effective (when enabled) as an AsyncPostBackTrigger
  • For the textboxes, I've tried variations of how to assign the textbox values (e.g. Textboxt1.text = value;   TextBox1.Attributes.Add("value", value1);
  • Additionally instead of using an asp:Textbox, I've tried using: <input type="text"  id="TextBox1" runat="server" />

Is what I'm trying to do even possible - what am I missing?


   <asp:Timer runat="server" ID="ContactsTimer" Interval="100" Enabled="false" OnTick="ContactsTimer_Tick" />
   <asp:UpdatePanel ID="upnlContacts" runat="server" UpdateMode="Conditional" >  
      <ContentTemplate>
         <asp:Label ID="lblContactAccountID" runat="server"/>
         <asp:TextBox ID="txtContactFirstName" runat="server"/> 
<%--edit: also tried:
            <input type="text"  id="txtContactFirstName" runat="server" />--%>
      </ContentTemplate>
      <Triggers>
         <asp:AsyncPostBackTrigger ControlID="ContactsTimer" EventName="Tick" />
      </Triggers>
   </asp:UpdatePanel>

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private void LoadSelectedContact(int personID)
   {
      DataTable dt = GetProfileContacts(personID, true);
      if (dt.Rows.Count > 0)
      {
         foreach (DataRow row in dt.Rows)
         {
            lblContactAccountID.Text = row["PersonID"].ToString(); 
            txtContactFirstName.Text = row["FirstName"].ToString();

// edit: also tried the below without success
//            string FirstName = row["FirstName"].ToString();
//            txtContactFirstName.value= FirstName;
//            txtContactFirstName.Attributes.Add("value", FirstName);


            // ...
            ContactsTimer.Enabled = true;
         }
      }
   }

   protected void ContactsTimer_Tick(object sender, EventArgs e)
   {
      ContactsTimer.Enabled = false;
      upnlContacts.Update();
   }

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Edit: I added (above) an example of the '<input type="text" ...  ' that I've tried without success. Below is the Gridview markup and the associated codebehind:


<asp:GridView ID="gvContacts" runat="server" CssClass="table table-striped solid-top" AutoGenerateColumns="false"
   DataKeyNames="PersonID" OnRowCommand="gvContacts_RowSelected">
   <Columns>
      <asp:BoundField DataField="PersonID" />
      <asp:TemplateField HeaderText="Name" ItemStyle-Width="10%" ItemStyle-HorizontalAlign="Center">
         <ItemTemplate>
            <asp:LinkButton runat="server" CommandName="Selected" CommandArgument="<%# Container.DataItemIndex %>"><%#Eval("LastName")%></asp:LinkButton>
            <asp:LinkButton runat="server" CommandName="Selected" CommandArgument="<%# Container.DataItemIndex %>"><%#Eval("FirstName")%></asp:LinkButton>
         </ItemTemplate>
      </asp:TemplateField>
      <asp:TemplateField HeaderText="Action" ItemStyle-Width="10%" ItemStyle-HorizontalAlign="Center">
         <ItemTemplate>
            <asp:ImageButton runat="server" ImageUrl="~/Images/icon_pencil.png" ToolTip='<%# "Edit Profile for "  + Eval("firstname") + " " + Eval("lastname") %>' CommandName="Edit" CommandArgument="<%# Container.DataItemIndex %>" />
         </ItemTemplate>
      </asp:TemplateField>
   </Columns>
</asp:GridView>

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protected void gvContacts_RowSelected(object sender, GridViewCommandEventArgs e)
{
   GridViewRow row;
   if (e.CommandSource.ToString() == "System.Web.UI.WebControls.ImageButton")
   {
      row = (GridViewRow)((ImageButton)e.CommandSource).NamingContainer;
   }
   else
   {
      row = (GridViewRow)((LinkButton)e.CommandSource).NamingContainer;
   }
   int personID = Int32.Parse(row.Cells[0].Text);
   switch (e.CommandName)
   {
      case "Selected":
         LoadSelectedContact(personID);
         break;
      //case "Edit" ...
   }
}

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ASKER CERTIFIED SOLUTION
David H.H.Lee
Digital Marketing (Hospitality)
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