Load GridView data within Panel which is displayed by ModalPopupExtender

I have a modal pop up extender that is used to dispaly a panel which has a grid view.
Currently the panel has a grid view which is bound to a sql data source.
Also there is an OnLoad method that is invoked to get the data on Page Load.

I do not want to have an OnLoad method bt default, I only want to get the data if the user has clicked the link button, how can I achieve this
Below is the code with the OnLoad feature

<ajaxToolkit:ModalPopupExtender ID="mpSelect" runat="server"
                   TargetControlID="lnkSelect" 
                   PopupControlID="pnlSelect"
                   DropShadow="True" 
                   CancelControlID="btnCancel" 
                    OnCancelScript="CloseModal('client');"
                   OnLoad="LoadSelect"
                   BackgroundCssClass="BackgroundStyle"
                    BehaviorID="pnlSelect"
               />
			   
			    <asp:LinkButton ID="lnkSelect" runat="server" OnClientClick="OpenModal('client')" ></asp:LinkButton>

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