Which big brother can help me see what is wrong with the binding of DropDownList and DataGrid?

helenwow

Changing while to if does not work either

helenwow

SqlCommand cmd = new SqlCommand ("select class, course from teaching plan, subject, teacher status table where teaching plan. Teacher = teacher status table. Teacher number and subject. ID = teaching plan. ID and teacher status table. Name = '" + Session ["TeacherName"]. ToString () + "'", conn);
Is such a database connection wrong?