inline code doesn't fire method

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C#

ASP.NET

I have a class Name PermissionControl in class folder.
when I use it in in inline code it doesn't fire

public class PermissionControl
    {
private static readonly HttpSessionState Session = HttpContext.Current.Session;
private static readonly HttpApplicationState Application = HttpContext.Current.Application;
        public static bool CheckPermission(string PermissionConstantName)
        {
           //my code
        }
}

and I call it here:

<asp:LinkButton ID="btn1" Visible='<%# CustomPermission.Class.PermissionControl.CheckPermission("Install") %>' runat="server">install module</asp:LinkButton>

why method doesn't fire?
I even set a break point but don't even call my method!