private void DisplayScan()
    {
      /*  int key = Convert.ToInt32();
        var dc = new PassingWeb.Data.PassingDataDataContext();
        Binary query = null;
        query = dc.v_PassportScans.Where(r => r.idPersonPass == key).Select(r => r.PassportPhoto).First();
        Scan.ContentBytes = query.ToArray();*/
            MessageBox.Show("+");
    }

  <dx:ASPxCallbackPanel ID="ASPxCallbackPanel1" ClientInstanceName="cp" runat="server"  ClientSideEvents-EndCallback="DisplayScan"> 
                        <PanelCollection> <dx:PanelContent runat="server" >
                                    <dx:ASPxPopupControl ID="pas" ClientInstanceName="pas" runat="server" AllowDragging="true" EnableClientSideAPI="False"
                                      PopupHorizontalAlign="NotSet" HeaderText="Паспорт" Height="500px" Width="700px" AllowResize="True" >
                                        <ContentCollection>
                                             <dx:PopupControlContentControl runat="server">
                                                    <dx:ASPxBinaryImage runat="server" ID="Scan" ></dx:ASPxBinaryImage>
                                             </dx:PopupControlContentControl>
                                            </ContentCollection>
                                        </dx:ASPxPopupControl>
                                 </dx:PanelContent>   
                            </PanelCollection>
                        </dx:ASPxCallbackPanel>

   <dx:ASPxCallbackPanel ID="ASPxCallbackPanel1" ClientInstanceName="cp" runat="server" >
                                 <ClientSideEvents  EndCallback="DisplayScan"/>
                        <PanelCollection> <dx:PanelContent runat="server" >
                                    <dx:ASPxPopupControl ID="pas" ClientInstanceName="pas" runat="server" AllowDragging="true" EnableClientSideAPI="False"
                                      PopupHorizontalAlign="NotSet" HeaderText="Паспорт" Height="500px" Width="700px" AllowResize="True" >
                                        <ContentCollection>
                                             <dx:PopupControlContentControl runat="server">
                                                    <dx:ASPxBinaryImage runat="server" ID="Scan" ></dx:ASPxBinaryImage>
                                             </dx:PopupControlContentControl>
                                            </ContentCollection>
                                        </dx:ASPxPopupControl>
                                 </dx:PanelContent>   
                            </PanelCollection>
                        </dx:ASPxCallbackPanel>