Asp.net ajaxfileupload不显示“；选择文件"；对话

我正在开发一个内部web应用程序，它收集各种图像并自动将它们绘制到一个更大的图像上。我在使用微软的AJAX工具包中的ajaxFileUpload控件时遇到了问题

在页面中，用户可以选择在文本框中填写ID号，然后单击按钮获取一些文本数据（图像的元数据）并填充两个文本框/下拉列表。用户还可以选择单击按钮从本地系统上载图像进行处理。ajaxFileUpload控件位于UpdatePanel上

当用户使用“填充”功能检索元数据，然后选择上载图像时，“选择文件”按钮不会触发本地系统上的“打开文件”对话框

当用户在检索元数据之前首次尝试上载图像时，“选择文件”按钮会弹出“打开文件”对话框，允许用户选择所需的文件

ajaxFileUpload控件在第一种情况下按预期工作；我假设如果我真的可以选择要上传的文件，那么剩下的过程就可以了

需要发布什么代码才能尝试解决此问题？ASPX？后端VB

标记：

将

AjaxFileUpload

控件放置到UpdatePanel的原因是什么？我将其用作ModalPopupXtender的PopupControlID。它会清理接口。

<asp:UpdatePanel runat = "server" ID = "upMain" >
    <ContentTemplate>
        <asp:Label runat = "server" ID = "lblImageBuilderTitle" Text = "Image Builder" CssClass = "panelTitle" />
        <asp:Table runat = "server">
            <asp:TableRow>
                <asp:TableCell HorizontalAlign = "Right" Width = "10%">
                    <asp:Label runat = "server" Text = "JTN: " />
                </asp:TableCell>
                <asp:TableCell>
                    <asp:TextBox runat = "server" ID = "tbJTN" /><asp:Button runat = "server" ID = "btnPopulate" Text = "+" />
                </asp:TableCell>
            </asp:TableRow>
            <asp:TableRow>
                <asp:TableCell HorizontalAlign = "Right" Width = "10%">
                    <asp:Label runat = "server" Text = "Job Ref: " />
                </asp:TableCell>
                <asp:TableCell>
                    <asp:TextBox runat = "server" ID = "tbJobRef" />
                </asp:TableCell>
            </asp:TableRow>
            <asp:TableRow>
                <asp:TableCell HorizontalAlign = "Right" Width = "10%">
                    <asp:Label runat = "server" Text = "Customer: " />
                </asp:TableCell>
                <asp:TableCell>
                    <asp:DropDownList runat = "server" ID = "ddlImageBuilderCustomer" />
                </asp:TableCell>
            </asp:TableRow>
            <asp:TableRow>
                <asp:TableCell HorizontalAlign = "Right" Width = "10%">
                    <asp:Label runat = "server" Text = "Type: " />
                </asp:TableCell>
                <asp:TableCell>
                    <asp:DropDownList runat = "server" ID = "ddlImageBuilderType" AutoPostBack = "true" />
                </asp:TableCell>
            </asp:TableRow>
            <asp:TableRow>
                <asp:TableCell HorizontalAlign = "Right" Width = "10%">
                    <asp:Label runat = "server" Text = "Email to Deana: " />
                </asp:TableCell>
                <asp:TableCell>
                    <asp:CheckBox runat = "server" ID = "cbEmailDeana" Checked = "true" />
                </asp:TableCell>
            </asp:TableRow>
            <asp:TableRow>
                <asp:TableCell HorizontalAlign = "Right" Width = "10%">
                    <asp:Label runat = "server" Text = "Email to Amy: " />
                </asp:TableCell>
                <asp:TableCell>
                    <asp:CheckBox runat = "server" ID = "cbEmailAmy" />
                </asp:TableCell>
            </asp:TableRow>
            <asp:TableRow>
                <asp:TableCell HorizontalAlign = "Right" Width = "10%">
                    <asp:Label runat = "server" Text = "Rego Branding: " Visible = "false" />
                </asp:TableCell>
                <asp:TableCell>
                    <asp:CheckBox runat = "server" ID = "cbRegoBranding" Visible = "false" />
                </asp:TableCell>
            </asp:TableRow>
            <asp:TableRow>
                <asp:TableCell ColumnSpan = "2" HorizontalAlign = "Center">
                    <asp:Label runat = "server" Text = "Images: " /><br />
                    <asp:GridView runat = "server" ID = "gvImages" AutoGenerateColumns = "false" AutoGenerateSelectButton = "false">
                        <Columns>
                            <asp:TemplateField>
                                <ItemTemplate>
                                    <asp:Label runat = "server" ID = "lblOriginalName" Text = "<%# Bind('original_filename') %>" />
                                </ItemTemplate>
                            </asp:TemplateField>
                            <asp:TemplateField>
                                <ItemTemplate>
                                    <asp:Button runat = "server" ID = "btnRowUp" CommandName = "Reorder" CommandArgument = "Up" />
                                    <asp:Button runat = "server" ID = "btnRowDown" CommandName = "Reorder" CommandArgument = "Down" />
                                </ItemTemplate>
                            </asp:TemplateField>
                        </Columns>
                        <EmptyDataTemplate>No images uploaded.</EmptyDataTemplate>
                    </asp:GridView>
                </asp:TableCell>
            </asp:TableRow>
        </asp:Table>
        <asp:ModalPopupExtender runat = "server" ID = "mpePopulate" TargetControlID = "btnPopulateDummy" PopupControlID = "pnlPopulate" BackgroundCssClass = "modalBackground" />
        <asp:Button runat = "server" ID = "btnPopulateDummy" CssClass = "invisible" />
        <asp:ModalPopupExtender runat = "server" ID = "mpeUpload" TargetControlID = "btnUpload" PopupControlID = "pnlUpload" CancelControlID = "btnUploadClose" BackgroundCssClass = "modalBackground" />
        <asp:Button runat = "server" ID = "btnUpload" Text = "Upload Images" />
    </ContentTemplate>
    <Triggers>
        <asp:AsyncPostBackTrigger ControlID = "gvPopulate" EventName = "SelectedIndexChanged" />
        <asp:AsyncPostBackTrigger ControlID = "btnUploadClose" EventName = "Click" />
        <asp:AsyncPostBackTrigger ControlID = "gvImages" EventName = "DataBound" />
        <asp:AsyncPostBackTrigger ControlID = "ajuImageUpload" EventName = "UploadComplete" />
    </Triggers>
</asp:UpdatePanel>

Private Sub ImageBuilder_PreRender(sender As Object, e As System.EventArgs) Handles Me.PreRender
    Dim dtIBImages As New DataTable
    If IsPostBack = False Then
        BindCustomerDDL("ImageBuilder")
        BindCategoryDDL("ImageBuilder")
        BindTemplatesDDL()
        'Session("dtIBImages") = Nothing

        'dtIBImages.Columns.Add("id")
        'dtIBImages.Columns.Add("original_filename")
        'dtIBImages.Columns.Add("image_filename")
        'dtIBImages.Columns.Add("disposition")

        '    Session("dtIBImages") = dtIBImages
    Else
        dtIBImages = Session("dtIBImages")
        gvImages.DataSource = dtIBImages
        gvImages.DataBind()
    End If
    dtIBImages = Session("dtIBImages")
    gvImages.DataSource = dtIBImages
    gvImages.DataBind()
End Sub