来自用户控件ASP.NET的AjaxFileUpload回发事件

Question

I have a AjaxFileUpload control in a usercontrol which is loaded dynamicaly on Postback, the problem here is, once the file is uploaded IsPostBack is false due to which the usercontrol is not loaded, causing the OnUploadCompleteAll event to not be triggered.

I found out that AjaxFileUpload control has its own postback property AjaxFileUpload.IsInFileUploadPostBack , how do i access this property from my main WebForm1.aspx page?

When an event is triggered from AjaxFileUpload i would like to check IsInFileUploadPostBack on page load of WebForm1.aspx and then load the usercontrol.

here is the code.

WebForm1.aspx

<form id="form1" runat="server">
        <asp:ScriptManager ID="ScriptManager1" runat="server"></asp:ScriptManager>
        <asp:Button ID="Button1" runat="server" Text="Load Control" OnClick="Button1_Click" />
        <asp:PlaceHolder ID="Placeholder1" runat="server" />

    </form>

Codebehind

protected void Page_Load(object sender, EventArgs e)
        {
            if (IsPostBack)
                loadcontrol();
        }

        protected void Button1_Click(object sender, EventArgs e)
        {

        }

       private void loadcontrol()
        {
            this.Placeholder1.Controls.Clear();
            var _controls = LoadControl("~/WebUserControl1.ascx");
            this.Placeholder1.Controls.Add(_controls);
        }

WebUserControl1.ascx

<%@ Control Language="C#" AutoEventWireup="true" CodeBehind="WebUserControl1.ascx.cs" Inherits="AjaxFileUpload_Test.WebUserControl1" %>
<%@ Register Assembly="AjaxControlToolkit" Namespace="AjaxControlToolkit" TagPrefix="ajaxToolkit" %>

<div id="div1">

        <ajaxToolkit:AjaxFileUpload ID="AjaxFileUpload1" UseAbsoluteHandlerPath="false" OnUploadCompleteAll="AjaxFileUpload1_UploadCompleteAll" OnUploadStart="AjaxFileUpload1_UploadStart" runat="server" />
</div>

Answer 1

Is there any specific reason you are loading the usercontrol from codebehind? An ajax control does not create an actual postback which is why that is always false. For what you seem to want you should use a NON-ajax file upload.

Answer 2

Got it working !!

Since i have to load the controls only then will i be able to access AjaxFileUpload.IsInFileUploadPostBack property, i decided to take an unorthodox approach.

Added below code to Page_Init

//to load the controls if AsyncFileUpload causes a postback
//the URL should contain the ID of the control in its context query string
    if (Request.HttpMethod.Contains("POST") && Request.Url.AbsoluteUri.Contains("AjaxFileUpload1"))
          loadcontrol();