你将: public class CompareByAge:IComparer { public int Compare(object a, object b) { return (((Employee)a).Age <= ((Employee)b).Age) ? 1: -1; } } 改一下就可以: public class CompareByAge:IComparer { public int Compare(object a, object b) { if (a == b || b == null) { return 1; } if (a == null) { return -1; } return (((Employee)a).Age <= ((Employee)b).Age) ? 1: -1; } }
public class CompareByAge:IComparer
{
public int Compare(object a, object b)
{
return (((Employee)a).Age <= ((Employee)b).Age) ? 1: -1;
}
}
改一下就可以:
public class CompareByAge:IComparer
{
public int Compare(object a, object b)
{
if (a == b || b == null) {
return 1;
}
if (a == null) {
return -1;
}
return (((Employee)a).Age <= ((Employee)b).Age) ? 1: -1;
}
}