public void GetAllCourseCodeByDepartment()
{
Courses _Course = new Courses();
_Course.DepartmentId = Convert.ToInt32(DepartmentDropDownList.SelectedValue);
CourseDropDownList.DataSource = _CourseAssigneManager.GetAllCourseCodeByDepartment(_Course.DepartmentId);
CourseDropDownList.DataTextField = "CourseCode";
CourseDropDownList.DataValueField = "Id";
CourseDropDownList.DataBind();
CourseDropDownList.Items.Insert(0, new ListItem("Select Course Code", "0"));
}