How to show a error when a modal popup extender is active

Question

I have a ModalPopupExtender to create new users. When the user enters the new user details and tries to enter the same email Id which is already registered then I want to show a error.

Create user:

  if (emailcount != 0)
            {
                
                Page.ClientScript.RegisterStartupScript(GetType(), "UserDialogScript", 

"alert(\"User already exists!\");", true);
            }

I check whether the email is already used, if it is used I want to pop up the error but the page stays still with the ModalPopupExtender on the top. I am not able to do anything after that. How can I display the error?

Answer 1

I would use a different approach for this. In your modal popup extender, try something like this:

<asp:UpdatePanel ID="pnlUserDetails" runat="server">
    <ContentTemplate>
        <asp:TextBox ID="txtEmail" runat="server" OnTextChanged="txtEmail_OnTextChanged" AutoPostBack="true"></asp:TextBox>
        <asp:Label ID="lblEmailMessage" runat="server" Text="Already exists!" Visible="false" /> 
    </ContentTemplate>
</asp:UpdatePanel>

In the code-behind:

protected void txtEmail_TextChanged(object sender, EventArgs e)
{
    //check for matching email address and show label if match is found
    lblEmailMessage.Visible = FindMatchingEmailAddress(txtEmail.Text.Trim());    

    //clear the email input if a match is found??
    txtEmail.Text = String.Empty;
}