ModalPopupExtender在dropdownlist的選定索引更改後消失

Question

我想從下拉列表中選擇的索引更改中獲得一些值，並將它們綁定到textox或其他控件，但問題是彈出在所選索引更改後消失。需要解決。 代碼

<ajaxToolkit:ToolkitScriptManager ID="ToolkitScriptManager1" runat="server"> 
    </ajaxToolkit:ToolkitScriptManager> 
    <div> 
     <div> 
     <div> 
       <asp:Button ID="Button1" runat="server" onclick="Button1_Click" Text="Button" /> 
      <asp:ModalPopupExtender ID="Button1_ModalPopupExtender" runat="server" 
       Drag="True" DropShadow="True" DynamicServicePath="" Enabled="True" 
       OkControlID="btncancel" PopupControlID="Panel1" TargetControlID="Button1"> 
      </asp:ModalPopupExtender> 

     </div> 
     </div> 
    </div> 
     <asp:Panel ID="Panel1" runat="server"> 
     first name<asp:TextBox ID="TextBox5" runat="server"></asp:TextBox> 
     <br /> 
     country <asp:DropDownList ID="DropDownList1" runat="server" AutoPostBack="True" 
      onselectedindexchanged="DropDownList1_SelectedIndexChanged"> 
      <asp:ListItem>select</asp:ListItem> 
      <asp:ListItem>india</asp:ListItem> 
      <asp:ListItem>pakistan</asp:ListItem> 
      <asp:ListItem>usa</asp:ListItem> 
      <asp:ListItem>england</asp:ListItem> 
     </asp:DropDownList> 
     <asp:RequiredFieldValidator ID="RequiredFieldValidator1" runat="server" 
      ControlToValidate="DropDownList1" ErrorMessage="*" InitialValue="select"></asp:RequiredFieldValidator> 
     <br /> 
     selected country<asp:TextBox ID="TextBox9" runat="server"></asp:TextBox> 
     <br /> 
     <asp:Button ID="Button2" runat="server" onclick="Button2_Click" Text="Submit" /> 
     <input id="btncancel" type="button" value="Cancel" /> 
    </asp:Panel> 

和代碼背後，是

protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e) 
    { 
     TextBox9.Text = DropDownList1.SelectedValue; 
    } 

Answer 1

我相信，你只需要重新發出show方法：

protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e) 
{ 
    TextBox9.Text = DropDownList1.SelectedValue; 
    Button1_ModalPopupExtender.Show(); 
}