为了去重复，写了一个通用的比较容器类，可以用在需要比较的地方，且支持Lamda表达式

    public class DataComparer<T>:IEqualityComparer<T> where T:class
    {
        private Func<T, T, bool> _compareFunc;

        public DataComparer(Func<T,T,bool> compareFunc)
        {
            this._compareFunc = compareFunc;
        }

        public bool Equals(T x, T y)
        {
           return  this._compareFunc(x, y);
        }

        public int GetHashCode(T obj)
        {
            return obj.GetHashCode();
        }
    }

dataTable.AsEnumerable().Distinct(new DataComparer<DataRow>((x, y) =>  return (x[1] == y[1] && x[2] ==y[2]))).CopyToDataTable();