// 排序
private int Sort1(DAL.StudentEntity x, DAL.StudentEntity y)
{
if (string.IsNullOrEmpty(x.DiplomaNumber))
{
x.DiplomaNumber = "";
}
if (string.IsNullOrEmpty(y.DiplomaNumber))
{
y.DiplomaNumber = "";
}
return(x.DiplomaNumber.CompareTo(y.DiplomaNumber));
}