Conditionally display Alert Message Box based on Label text (value) in ASP.Net

 i have a label  and read the value from  the laebl in C# code then check if value grater then 200 then cannot allow follwoing my code

 string mylabel = mylabel.Text;
        if (mylabel <= 200)
        {
                 ScriptManager.RegisterClientScriptBlock(Page, typeof(Page), "Warning", "<script>alert('cannot allow, false);
        }
      

please help me how i solved it