Issue with ModalPopup in asp.net/C#

I have used modalpopup control in my web application and after open it when i click on ok button i have make call to WCF function to deal with some functional requirement.

Currently the behavior like , when i will click on OK button ModalPopup remained open until my WCF operation is completed and when it will completed it will be closed because i write down logic to hide in code behind file and my code as per below

  <asp:Panel ID="PanelCheck" runat="server" CssClass="modalPopup" SkinID="Custom">
        *Panel content here..*
        <asp:Button ID="OkButton" runat="server" Text="Create" OnClientClick="return  
         ValidateSeconds();" OnClick="OkButton_Click" /> 

  </asp:Pane开发者_开发技巧l>

<cc1:modalpopupextender id="MPE" runat="server" targetcontrolid="lnkTemp"  
 popupcontrolid="PanelCheck" backgroundcssclass="modalBackground" />

code behind

    protected void OkButton_Click(object sender, EventArgs e)
    {
        if (Page.IsValid)
        {
            try
            {
                MPE.Hide();

                     *Logic to deal with WCF call..* 

                }
            }
            catch (Exception ex)
            {
                throw ex;
            }

            timerInstance.Enabled = true;
        }
    }

Now what i require is i need to close modalpopup first and then asynchronously it should make WCF call I could not find any ways to do that, please anyone help me if this question make any sense.

Thanks in Advance

I believe you can hide ModalPopupExtender on the client side right after clicking the “Create” button:

<asp:Button ... OnClientClick="return ValidateSeconds();" /> 

function ValidateSeconds() {
    //your code
    $find('MPE').hide();
    //your code
}

See Also:

How to Show / Hide a ModalPopupExtender using Javascript