class Program
    {
        static void Main(string[] args)
        {
            DataTable dt = new DataTable();
            dt.Columns.Add("A");
            dt.Columns.Add("B");
            dt.Columns.Add("C");
            dt.Columns.Add("D");
            dt.Columns.Add("E");
            for (int i = 0; i < 10; i++)
            {
                DataRow row = dt.NewRow();
                row["A"] = i;
                row["B"] = i;
                row["C"] = i;
                row["D"] = i;
                row["E"] = i;
                dt.Rows.Add(row);
            }

            string[] columns = new string[] { "A", "B", "C" };

           DataTable ret = ShowTable(dt, columns);
        }

        static DataTable ShowTable(DataTable dt, string[] columns)
        {
            var r = (from o in dt.Columns.Cast<DataColumn>()
                    where !columns.Contains(o.ColumnName)
                    select o.ColumnName).ToList().Distinct();
            foreach (var colname in r)
            {
                dt.Columns.Remove(colname);
                
            }
            return dt;
        }
    }

------解决方案--------------------
C# code
private DataTable ShowTable(DataTable dt, string[] columns)
{
    var targetDt = dt.Copy();
    foreach(var col in targetDt .Columns)
    {
         if (!columns.Contains(col.ColumnName))
            targetDt .Columns.Remove(col);
    }
    return targetDt;
}

------解决方案--------------------

http://blog.csdn.net/q107770540/article/details/6556210
看看这个

------解决方案--------------------

这样做不是很浪费,把不要的子段查出来,然后有删除掉..........为何不找一个只要查询自己需要的字段呢

Linq实现这种随时变化的好像有点麻烦: http://www.4ucode.com/Study/Topic/1600