private void cmbGetAllGrade() //获取年级的方法 { List <GradeInfo> gradeInfo = bllCommon.GetAllGradeInfo(); gradeInfo.Insert(0, new GradeInfo { GradeName = "——请选择年级——", GradeInfoID = 0 }); cmbGrade.DisplayMember = "GradeName"; cmbGrade.ValueMember = "GradeInfoID"; cmbGrade.DataSource = gradeInfo; }