Ajax Modal Popup Extender

• TargetControlID button is usually hidden (Style="display:none;")
• Reason: you might want to show the popup via mdlMyModal.Show() from within a GridView click on a row, and you might have to get all the data to populate the form. Ajax says you still need the button.
• One button per modal: btnDummy1, btnDummy2, etc.

<%@ Register Assembly="AjaxControlToolkit" Namespace="AjaxControlToolkit" TagPrefix="ajax" %>

<Ajax:ModalPopupExtender ID="mdlPopupReason" runat="server" TargetControlID="btnTargetControl2" 
	PopupControlID="pnlPopupReason" CancelControlID="btnCancel2" BackgroundCssClass="modalBackground" />
    <asp:Button ID="btnTargetControl2" runat="server" EnableViewState="false" CausesValidation="false" Style="display:none;"/>
    <asp:Panel ID="pnlPopupReason" runat="server" CssClass="modalPopup" Style="display:none;">
        <asp:ValidationSummary ID="vldSummary" runat="server" CssClass="validation" 
			Style="margin-bottom: 10px;margin-top: -5px;" EnableClientScript="true" 
			DisplayMode="BulletList" 
			HeaderText="<b>The Following Error(s) Occurred:</b>" 
			ShowSummary="true" ValidationGroup="Reason" Visible="true" />
        <h2>Reject Offers</h2>
        <div class="group">
            <label class="label">Proceed with the rejection of the selected offer(s) by providing a reason:</label>
            <br />
            <div class="calign"><asp:DropDownList ID="ddlReason" runat="server" CssClass="w250 requiredField" /></div>
            <asp:RequiredFieldValidator ID="vldReason" runat="server" ControlToValidate="ddlReason" Display="None" 
			ErrorMessage="A reason is required." InitialValue="-1" ValidationGroup="Reason" />
        </div>
        <div class="clear"></div>
        <div class="calign">
            <asp:Button ID="btnReject" runat="server" CssClass="submitButton" Text="Reject" OnClick="btnReject_Click" ValidationGroup="Reason"/>
            <asp:Button ID="btnCancel2" runat="server" SkinID="cancelButton" EnableViewState="false" CausesValidation="false"/>
        </div>
    </asp:Panel>

protected void btnReject_Click(object sender, EventArgs e)
{
	try
	{
		if (Page.IsValid)
		{
			// Do stuff
		}
		else
		{
			mdlPopupReason.Show();
		}
	}
	catch (System.Exception ex)
	{
		HandleError(ex);
	}
}