您可以使用
OnUploadedComplete事件显示图像。
<ajaxToolkit:AsyncFileUpload ID="AsyncFileUpload1" Width="400px" runat="server" onUploadedComplete="ProcessUpload"protected void ProcessUpload(object sender, AjaxControlToolkit.AsyncFileUploadEventArgs e){string fileName = Server.MapPath("./") + "image.jpg";AsyncFileUpload1.SaveAs(fileName);scriptManager.RegisterClientscriptBlock(AsyncFileUpload1, AsyncFileUpload1.GetType(), "img", "top.document.getElementById('imgUpload').src='image.jpg';", true);}有关如何显示预览的详细信息，请看以下示例：具有AsyncFileUpload控件的ASP.NET中的AJAX文件上传
