Upload a file to server automatically inside a update panel in asp.net website

问题

I have a file upload inside the update panel, and an upload button that uploads the file to the server. Is it possible to upload the file without clicking the upload button? I want to remove the upload button and upload the file as soon as the file is selected from the user's machine. Or, have a 4 second timer, then call the upload_click to check if the fileupload has a file or not. How can I do it without a button inside update panel?

<asp:UpdatePanel ID="UP_DDL" runat="server" UpdateMode="Always" ChildrenAsTriggers="true">
    <ContentTemplate> 
        <asp:FileUpload ID="FileUpload1" runat="server" />
        <asp:Button ID="Upload" OnClick="Upload_Click" runat="server" Text="Upload" />
    </ContentTemplate>
    <Triggers>
        <asp:PostBackTrigger ControlID="Upload"/>
    </Triggers>
</asp:UpdatePanel>

protected void Upload_Click(object sender, EventArgs e)
{
    if (FileUpload1.HasFile)
    {
        //create the path to save the file to     
        string fileName = Path.Combine(Server.MapPath("~/Bulk Upload"), FileUpload1.FileName);
        //save the file to our local path  
        FileUpload1.SaveAs(fileName);
    }
}

回答1:

I am sure you can use any of the events on the HTML INPUT File element to fire up a full post back, which is all you need in order to upload the file automatically.

Google, at least on the standard interface, uses some sort of Flash plugin to accomplish what you want.

There might be some other jQuery plugins that provide this functionality out of the box. This one, for example, seems to do it.

回答2:

You would need to mimic the click with some client-side code, such as using submit from Javascript - and this is not supported by at least one notable browser, I believe, IE.

Otherwise, you could use jQuery ajax calls to static web methods which do uploads on the fly, behind the scenes, when the value of the file upload control have changed.

回答3:

You can hide Upload button with display:none inline style and add following code to Page_PreRender method:

FileUpload1.Attributes["onchange"] = ClientScript.GetPostBackClientHyperlink(Upload, "");

Or consider to use AsyncFileUpload control from AjaxControlToolkit

来源：https://stackoverflow.com/questions/8310832/upload-a-file-to-server-automatically-inside-a-update-panel-in-asp-net-website

标签

ASP.NET

ajax

updatepanel

ajaxcontroltoolkit