后台导出GridView到Excel，可选择要导出的列

前端的GridView不要用自动生成列，否则取不到列的资料，不知自动生成列有什么办法？

前端增加一个CheckBoxList用来显示GridView列，导出的时候选择：

    <asp:Panel ID="panel1" runat="server" Style="display: none; text-align: center;  500px;">
        <div style=" 500px; margin: 0 auto; border: 2px solid green; text-align: center;
            background-color: Silver;">
            <asp:Panel ID="Panel2" runat="server">
                <div class="thead" style="line-height: 30px; height: 30px; cursor:move;">
                    <span style="float: left; padding-left: 5px;">请选择要导出的列</span> <span style="float: right;
                        clear: both; padding-right: 5px;">
                        <img src="../icon/cancel.png" onclick="document.getElementById('panel1').style.display='none';"
                            style="vertical-align: middle; cursor:pointer;" alt="单击关闭" />
                    </span>
                </div>
            </asp:Panel>
            <asp:CheckBoxList ID="CheckBoxList1" runat="server" RepeatColumns="4" CellPadding="5"
                CellSpacing="0" RepeatDirection="Horizontal" Width="500px">
            </asp:CheckBoxList>
            <asp:Button ID="Button1" runat="server" Text="确定导出" CssClass="SmallButton" Style="margin: 5px 10px 5px 10px;
                float: right;" OnClick="Button1_Click" />
        </div>
    </asp:Panel>
    <asp:AlwaysVisibleControlExtender ID="AlwaysVisibleControlExtender1" runat="server"
        TargetControlID="panel1" HorizontalSide="Center" VerticalOffset="100">
    </asp:AlwaysVisibleControlExtender>
    <asp:DragPanelExtender ID="DragPanelExtender1" runat="server" TargetControlID="panel1" DragHandleID="Panel2">
    </asp:DragPanelExtender>

后端在加载时填充CheckBoxList:

protected void Page_Load(object sender, EventArgs e)
    {
        if (!IsPostBack)
        {
 
            for (int i = 0; i < GridView1.Columns.Count; i++)
            {
                if(GridView1.Columns[i] is BoundField)
                {
                    if (GridView1.Columns[i].Visible && GridView1.Columns[i].HeaderStyle.CssClass!="hide")
                    {
                        CheckBoxList1.Items.Add(new ListItem(GridView1.Columns[i].HeaderText, ((BoundField)this.GridView1.Columns[i]).DataField));
                    }
                }
            }
            for (int i = 0; i < CheckBoxList1.Items.Count; i++)
            {
                CheckBoxList1.Items[i].Selected = true;
            }
        }
    }

导出按钮：

    protected void Button1_Click(object sender, EventArgs e)
    {
        string text = "";
        string value="";
        for (int i = 0; i < CheckBoxList1.Items.Count; i++)
        {
            if (CheckBoxList1.Items[i].Selected)
            {
                text += CheckBoxList1.Items[i].Text + ",";
                value += CheckBoxList1.Items[i].Value + ",";
            }
        }
        if (text != "")
        {
            text = text.Substring(0, text.Length - 1);
            value = value.Substring(0, value.Length - 1);
            string[] oldColName = value.Split(',');
            string[] newColName = text.Split(',');

            //获取数据，代码根据需要自行编写
            System.Data.DataTable dt = getData().ToTable() ;
            ExcelHelper.ExportByWeb(dt, date1.Text + "~" + date2.Text + "工作表标题", "文件名.xls", "工作表名称",oldColName,newColName);
        }
    }

导出时调用的代码见另外一篇文章：

http://blog.csdn.net/apollokk/article/details/8025611