c# DataView.ToTable()方法 去除表的重复项问题

DataView dv = new DataView(table);
table = dv.ToTable(true, "ID");              //去重，返回原表中的ID列

//table=dv.ToTable(true,"ID","name");    //返回ID 和 name两列

/// <summary>
/// 合并表结构相同datatable数据
/// </summary>
public DataTable Mergedata(){
 DataTable data = new DataTable();
 DataTable deptdata = new DataTable(); 
 
 data=DBHelper.FillDataTable("select * from T1", null);
 deptdata=DBHelper.FillDataTable("select * from T2", null);

 data.Merge(deptdata, true); 
 return  data;
}

    /// <summary>
    /// 去除datatable重复数据
    /// </summary>
    public DataTable distinctdata() 
    {
     DataTable data = new DataTable();
     DataTable distinctdata = new DataTable();

      List<string> datarowlist = new List<string>();
      string[] datarow;
      
     foreach (DataColumn row in data.Columns) //遍历出表头
      {
       datarowlist.Add(row.ToString());
      }
     datarow = datarowlist.ToArray();
     
     DataView dv = new DataView(data);         
     distinctdata = dv.ToTable(true, datarow); //对表所有字段进行过滤，true表示使用distinct方法
     return  distinctdata;
}