Question

我正在使用asp.net，我有以下c＃方法将网格视图数据导出到Excel工作表，这个方法是通过ImageButton点击事件调用的：

public void GridToExcel()
{
    if (berthOccupancyDataGridView.Rows.Count > 0)
    {
        Response.Clear();
        Response.AddHeader("content-disposition", "attachment; filename=BerthOccupancy.xls");
        Response.ContentType = "application/vnd.xls";
        StringWriter sw = new StringWriter();
        HtmlTextWriter htw = new HtmlTextWriter(sw);
        berthOccupancyDataGridView.RenderControl(htw);

        if (reportType == "Year To Date")
        {
            foreach(GridView gv in gridViewList)
            {
                gv.RenderControl(htw);
            }
        }
        else
        {
            recapGridView.RenderControl(htw);

        }

        Response.Write(sw.ToString());
        Response.End();
    }
}

我有List存储动态创建的GridViews。问题是图像按钮触发PostBack并将此列表设置为null。我尝试了很多方法来阻止它进行PostBack，例如使用OnClienClick =＆＃34; return false;＆＃34;但它没有用。我尝试使用ScriptManager和WebMethods，但它需要将方法设置为static并将方法设置为static会显示以下错误：

错误2非静态字段，方法或属性需要对象引用“System.Web.UI.Page.Response.get＆＃39;

错误5非静态字段，方法或属性需要对象引用＆＃39; BerthOccypancyForm.berthOccupancyDataGridView＆＃39;

有没有办法在不使用WebMethods和PageMethods的情况下使用AJAX调用此方法？

感谢您的帮助..

Answer 1

我通过使用以下代码在PostBack中保留列表数据和变量来解决问题：

（这个答案的问题是会话数据在20分钟后默认超时。会话不用于存储大数据，例如gridviews）

这个用于保存GridViewList数据：

public List<GridView> Code
{
    get
    {
        if (HttpContext.Current.Session["Code"] == null)
        {
            HttpContext.Current.Session["Code"] = new List<GridView>();
        }
        return HttpContext.Current.Session["Code"] as List<GridView>;
    }
    set
    {
        HttpContext.Current.Session["Code"] = value;
    }

}

这个用于保存字符串数据：

  public string RT
    {
        get
        {
            if (HttpContext.Current.Session["RT"] == null)
            {
                HttpContext.Current.Session["RT"] = "" ;
            }
            return HttpContext.Current.Session["RT"] as string;
        }
        set
        {
            HttpContext.Current.Session["RT"] = value;
        }

    }

Answer 2

所以我在更新面板中有一个gridview控件，它基本上为用户提供了一个数据列表，如下所示：

 <asp:UpdatePanel runat="server" UpdateMode="Conditional" ChildrenAsTriggers="true">
                        <ContentTemplate>
                            <asp:GridView runat="server" ID="transactionGrid" CssClass="table table-bordered table-condensed table-striped"
                                AllowPaging="true" PageSize="8" AutoGenerateColumns="false" ShowHeaderWhenEmpty="true"
                                OnRowCommand="transactionGrid_RowCommand"
                                OnRowDataBound="transactionGrid_RowDataBound"
                                OnPageIndexChanging="transactionGrid_PageIndexChanging">
                                <Columns>
                                <asp:TemplateField>
                                    <HeaderTemplate>
                                        <a runat="server" href="~/PayrollManagement/Transaction/TransactionEntry.aspx" class="btn btn-success btn-outline btn-sm"><i class="fa fa-plus fa-fw"></i>&nbsp; Add</a>
                                    </HeaderTemplate>
                                    <ItemTemplate>
                                        <asp:LinkButton runat="server" ID="cmdPrint" CssClass="btn btn-success btn-outline ttip btn-sm" ToolTip="Print Batch" data-toggle="tooltip"
                                            CommandName="printBatch" CommandArgument="<%# ((GridViewRow) Container).RowIndex %>">
                                            <span><i class=" fa fa-print fa-fw"></i></span>
                                        </asp:LinkButton>
                                        <asp:LinkButton runat="server" ID="cmdExportCSV" CssClass="btn btn-success btn-outline ttip btn-sm" ToolTip="Export Batch" data-toggle="tooltip"
                                            CommandName="exportBatch" CommandArgument="<%# ((GridViewRow) Container).RowIndex %>">
                                            <span><i class=" fa fa-envelope fa-fw"></i></span>
                                        </asp:LinkButton>
                                        <asp:LinkButton runat="server" ID="cmbEditBatch" CssClass="btn btn-primary btn-outline ttip btn-sm" ToolTip="Edit Batch" data-toggle="tooltip"
                                            CommandName="editBatch" CommandArgument="<%# ((GridViewRow) Container).RowIndex %>">
                                            <span><i class=" fa fa-pencil fa-fw"></i></span>
                                        </asp:LinkButton>
                                        <asp:LinkButton runat="server" ID="cmdPost" CssClass="btn btn-danger btn-outline ttip btn-sm" ToolTip="Post Batch" data-toggle="tooltip"
                                            CommandName="postBatch" CommandArgument="<%# ((GridViewRow) Container).RowIndex %>">
                                            <span><i class=" fa fa-archive fa-fw"></i></span>
                                        </asp:LinkButton>
                                    </ItemTemplate>
                                </asp:TemplateField>
                                <asp:BoundField HeaderText="Batch ID" DataField="HEADERID" />
                                <asp:BoundField HeaderText="Payroll Name" DataField="PAYROLLNAME" />
                                <asp:BoundField HeaderText="Date Created" DataField="DATECREATED" dataformatstring="{0:MM/dd/yyyy}" htmlencode="false" />
                                <asp:BoundField HeaderText="Created By" DataField="CREATEDBY" />
                                <asp:BoundField HeaderText="Batch Date" DataField="BATCHDATE" dataformatstring="{0:MM/dd/yyyy}" htmlencode="false" />
                                <asp:BoundField HeaderText="Farm Name" DataField="FARMNAME" />
                                <asp:BoundField HeaderText="Batch Status" DataField="STATUSDESC" />
                                <asp:BoundField HeaderText="Batch Desc" DataField="BATCHDESC" />
                            </Columns>
                            <PagerStyle CssClass="pagination-ys" />
                            </asp:GridView>
                        </ContentTemplate>
                        <Triggers>
                            <asp:AsyncPostBackTrigger ControlID="cmdSearch" EventName="click" />
                            <asp:AsyncPostBackTrigger ControlID="cmdPostBatch" EventName="click" />
                        </Triggers>
                    </asp:UpdatePanel>

    <div hidden="hidden">
    <iframe src="../CSVExport/ExportToCsv.aspx" runat="server" id="csvFrame"></iframe>
</div>

在gridview中，您可以看到有一个exportBatch链接按钮，该按钮分配给每一行。因此，当用户单击exportBatch按钮时，我运行我的代码来编译csv，在您的情况下，它将导出到excel。

所以这是rowcommand method：

背后的代码

        protected void transactionGrid_RowCommand(object sender, GridViewCommandEventArgs e)
    {

        int index;
        GridViewRow row;
        int batchID;

        processPayBatch dal = new processPayBatch();
        switch (e.CommandName)
        {

            case "exportBatch":
                index = Convert.ToInt32(e.CommandArgument);
                row = transactionGrid.Rows[index];
                batchID = Convert.ToInt32(row.Cells[1].Text);

                Session["csvbatch"] = batchID;
                csvFrame.Attributes["src"] = "/CSVExport/ExportToCsv.aspx";

                //Download the CSV file.


                ScriptManager.RegisterStartupScript(this, this.GetType(), "", "window.frames[0].document.forms[0].submit();", true);
                break;

        }

    }

因此，当点击行按钮时，我会在iframe中提交表单。这是ExportToCsv页面的代码：

  protected void Page_Load(object sender, EventArgs e)
    {
        if (IsPostBack) {
            processPayBatch dal = new processPayBatch();
            int batchID = (int)Session["csvbatch"];
            Session["csvbatch"] = null;
            dal.ExportToCSV(batchID);

            string csv = dal.csvFile;
            HttpContext.Current.Response.Clear();
            HttpContext.Current.Response.Buffer = true;
            HttpContext.Current.Response.AddHeader("content-disposition", "attachment;filename=SqlExport.csv");
            HttpContext.Current.Response.Charset = "";
            HttpContext.Current.Response.ContentType = "text/csv";
            HttpContext.Current.Response.Output.Write(csv);
            HttpContext.Current.Response.Flush();
            HttpContext.Current.Response.End();
        }
    }

查询数据库并检索必要的信息并将其编译为csv文件。

我选择使用iframe的原因是因为如果我必须在后面的gridview代码中执行它（因为更新面板），response.write没有运行。

Answer 3

谢谢你们的建议。我能够以这种方式解决它。

我添加了一个静态类，它有静态List和静态字符串。我在WebForm中称这个类。这样在PostBack期间保留GridViews的数据

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Data;
using System.Web.UI.WebControls;
/// <summary>
/// Summary description for Global
/// </summary>
public static class Global
{

    public static List<GridView> GridViewList = new List<GridView>();
    public static string ReportType = "";
}

以下C＃函数使用静态类中的数据导出到excel。

public  void GridToExcel()
{
    if (berthOccupancyDataGridView.Rows.Count > 0)
    {
        Response.Clear();
        //HttpContext.Current.Response.Buffer = true;
        Response.AddHeader("content-disposition", "attachment; filename=BerthOccupancy.xls");
        //HttpContext.Current.Response.Charset = "";
        Response.ContentType = "text/csv";

        StringWriter sw = new StringWriter();
        HtmlTextWriter htw = new HtmlTextWriter(sw);
        berthOccupancyDataGridView.RenderControl(htw);

        if (Global.ReportType == "Year To Date")
        {
            foreach (GridView gv in Global.GridViewList)
            {
                gv.RenderControl(htw);
            }
        }
        else if(Global.ReportType == "Monthly")
        {
            recapGridView.RenderControl(htw);

        }

        Response.Write(sw.ToString());
        Response.End();
    }
}

使用AJAX调用服务器端方法

3 个答案: