No more post back after file download in sharepoint

Question

I tried to download a file from sharepoint. But after I download this file, I can't click on other buttons. What is wrong with my coding?

This is my first way.

            Response.AppendHeader("content-disposition", "attachment; filename= " + fileName);
            Response.ContentType = "text/plain";
            Response.WriteFile(Server.MapPath("~/" + fileName));
            Response.End();

This is my second way

            byte[] bytes = System.IO.File.ReadAllBytes("D:\\" + fileName);

            Response.ClearContent();
            Response.ClearHeaders();
            Response.AddHeader("Content-Type", "application/octet-stream");
            Response.AddHeader("Content-Length", bytes.Length.ToString());

            Response.AddHeader("content-disposition", "attachment; filename= " + fileName);

            Response.BinaryWrite(bytes);
            Response.Flush();
            Response.End();

I even comment Response.End() but still the same result.

Is there any other way I should tried?

Any help would be really appreciated. In fact, I posted this question a few days ago, but only one gave me my second way to try but it is still not working.

Thanks.

UPDATE

Here is my GridView under GridView.

           <asp:GridView ID="gvGiro" Width="100%" runat="server" GridLines="Both" AllowPaging="false" CssClass="form-table" ShowHeader="false"
                AllowSorting="false" AutoGenerateColumns="false" OnRowDataBound="gvGiro_RowDataBound">
                <Columns>
                    <asp:TemplateField ItemStyle-Width="20%" ItemStyle-HorizontalAlign="Center">
                        <ItemTemplate>
                            <asp:Label ID="lblValueDate" Text='<%# getDate(Eval("ValueDate")) %>' runat="server" />
                        </ItemTemplate>
                    </asp:TemplateField>
                    <asp:TemplateField>
                        <ItemTemplate>

                            <asp:GridView ID="gvDetail" runat="server" AllowPaging="false" AllowSorting="false" 
                                CssClass="list-table border" HeaderStyle-CssClass="header" AutoGenerateColumns="false">
                                <Columns>
                                    <asp:TemplateField HeaderText="Sequence Number" ItemStyle-HorizontalAlign="Left"
                                        ItemStyle-Width="30%" >
                                        <ItemTemplate>
                                            <%#((DataRowView)Container.DataItem)["MessageSeqNbr"] %>
                                        </ItemTemplate>
                                    </asp:TemplateField>
                                    <asp:TemplateField HeaderText="Total Number of Debit Transaction" ItemStyle-HorizontalAlign="Left"
                                        HeaderStyle-HorizontalAlign="Center">
                                        <ItemTemplate>
                                            <%#((DataRowView)Container.DataItem)["TotalDebitNbr"] %>
                                        </ItemTemplate>
                                    </asp:TemplateField>
                                    <asp:TemplateField HeaderText="Status" ItemStyle-HorizontalAlign="Left" ItemStyle-Width="25%"
                                        HeaderStyle-HorizontalAlign="Center">
                                        <ItemTemplate>
                                            <%#((DataRowView)Container.DataItem)["CodeDesc"] %>
                                            <asp:HiddenField ID="hidCode" runat="server" Value='<%#((DataRowView)Container.DataItem)["Code"] %>' />
                                        </ItemTemplate>
                                    </asp:TemplateField>
                                    <asp:TemplateField HeaderText="Action" ItemStyle-HorizontalAlign="Center" ItemStyle-Width="10%"
                                        HeaderStyle-HorizontalAlign="Center">
                                        <ItemTemplate>
                                        <asp:Button ID="btnDownload" runat="server" CssClass="button submit" Text="Download" 
                                CommandName="download" OnCommand="onCmd" CommandArgument='<%#Eval("Id") %>' Width="80px"/>
                                        <asp:Button ID="btnUnbatch" runat="server" CssClass="button generic" Text="Un-Batch"
                                CommandName="unbatch" OnCommand="onCmd" CommandArgument='<%#Eval("Id") %>' Width="80px"/>
                                        </ItemTemplate>
                                    </asp:TemplateField>
                                </Columns>
                            </asp:GridView>
                        </ItemTemplate>
                    </asp:TemplateField>
                </Columns>
            </asp:GridView>

Here is my cs file

    protected void gvGiro_RowDataBound(object sender, GridViewRowEventArgs e)
    {
        GridView gr;
        if (e.Row.RowType == DataControlRowType.DataRow)
        {
            gr = (GridView) e.Row.FindControl("gvDetail");
            using (class2 ct2= new Class2())
            {
                Label lblValueDate = (Label)e.Row.FindControl("lblValueDate");
                DateTime dt= DateTime.MinValue;
                DataSet ds= ct2.GetData(dt);
                gr.DataSource = ds; 
                gr.DataBind();

            }

        }
    }


protected void onCmd(object sender, CommandEventArgs e)
    {
        string id;
        switch (e.CommandName)
        {
            case "unbatch":
                id= e.CommandArgument.ToString();
                Unbatch(id);
                break;
            case"download":
                id= e.CommandArgument.ToString();
                Download(id);
                break;
            default:
                break;
        }
    }

    protected void Download(string id)
    {
        // to do - substitute all hard-code guid
        Guid batchId = new Guid(id);
        string fileName = "";
        Class1 ct = new Class1();


        {
            if (!ct.FileExists(batchId , ref fileName))
            {
                byte[] bytes = System.IO.File.ReadAllBytes("D:\\" + fileName);
            Response.ClearContent();
            Response.ClearHeaders();
            Response.AddHeader("Content-Type", "application/octet-stream");
            Response.AddHeader("Content-Length", bytes.Length.ToString());
            Response.AddHeader("content-disposition", "attachment; filename= " + fileName);
            Response.BinaryWrite(bytes);
            Response.Flush();
            Response.End();
            }

Answer 1

SharePoint registers a JavaScript "on submit" handler. In this handler the global variable _spFormOnSubmitCalled is set to true. SharePoint uses this variable to check if a submit was executed and prevents any further submits. Since your "download postback" does not refresh the page this variable remains true. With the effect that that all other buttons stop working.

As a workaround you can set this variable to false in a client click handler on your download button:

Button btn = new Button();
btn.Text = "Download";
btn.Click += DownloadButton_Click;

// set the client click handler
btn.OnClientClick = "window.setTimeout(function() { _spFormOnSubmitCalled = false; }, 10);"

Of course thats a little hacky and is not garantueed to work in upcoming SharePoint versions.

Answer 2

There is an easy way to work around this. Register OnClientClick event for the button click and set _spFormOnSubmitCalled to false.

<asp:Button ID="Button1" runat="server" Text="Export" onclick="Button1_Click" OnClientClick="javascript:setFormSubmitToFalse()" />

And put the script below in the page/js file.

<script type="text/javascript">
    function setFormSubmitToFalse() {
        _spFormOnSubmitCalled = false;        
        return true;
    }
</script>