You must call your method like this:
protected void Page_Load(object sender, EventArgs e)
{
string pro_id="xxx";//you need to assign it or retrieve somewhere
string sta_id="xxx";//you need to assign it or retrieve somewhere
string ity_id="xxx";//you need to assign it or retrieve somewhere
MyMethod(pro_id, sta_id, ity_id);
}
When you call a method you don't have to write the type of the parameter. Just write the name of the variable who has the same type as the parameter.in your cas string