获取对固定列不重复的新DataTable 

    ///<summary>     
    /// 获取对固定列不重复的新DataTable    
    /// </summary>       
    ///<param name="dt">
    ///含有重复数据[shu ju]的DataTable  </param>        
    ///<param name="colName">  需要验证[yan zheng]重复的列名  </param>           
    ///<returns>  新的DataTable，colName列不重复，表格式保持不变  </returns>      
    private DataTable GetDistinctTable(DataTable dt, string colName)
    {
        DataView dv = dt.DefaultView;
        DataTable dtCardNo = dv.ToTable(true, colName);
        DataTable Pointdt = new DataTable();
        Pointdt = dv.ToTable();
        Pointdt.Clear();
        for (int i = 0; i < dtCardNo.Rows.Count; i++)
        {
            DataRow dr = dt.Select(colName + "='" + dtCardNo.Rows[i][0].ToString() + "'")[0];
            Pointdt.Rows.Add(dr.ItemArray);
        } return Pointdt;
    }