Caption的用途？？？？

C# code

            DataTable dt = new DataTable(); 
            dt.TableName = "内存表";//获取或设置表的名称        
            DataColumn datac = new DataColumn();        
            datac.Caption = "第一列";//获取或设置列的标题        
            datac.ColumnName = "no1";        
            DataColumn data2 = new DataColumn();        
            data2.Caption = "第二列";        
            data2.ColumnName = "no2";        
            DataColumn datal = new DataColumn();        
            datal.Caption = "第三列";        
            datal.ColumnName = "no3";        
            DataColumn[] cls=new DataColumn[3];        
            cls[0] = datac;        
            cls[1] = data2;        
            cls[2] = datal;        
            dt.Columns.AddRange(cls);        
            DataRow row1 = dt.NewRow();//使用该方法来生成行对象        
            row1[0] = "2000";        
            row1[1] = "2003";        
            row1[2] = "6003";        
            dt.Rows.Add(row1);        
            dt.AcceptChanges();//接受表的修改        
            this.GridView1.DataSource = dt;        
            this.GridView1.DataBind();

C# code

        <asp:GridView ID="GridView1" runat="server">
        </asp:GridView>

Caption究竟是什么功能？？
即不能用来访问row1["第三列"] = "6003"; 
也没有在GridView的列名显示
我是用net4.0的asp.net

MNDN

你可以把它当成一个额外存储