Asp. NET enables FileUpload controls to support the resolution of the automatic upload feature

Asp. NET fileupload control is not supported by default for server-side onchange events, this can be accomplished in a flexible way.
This requires borrowing the client's onchange event, calling the __doPostBack method to simulate an event-triggering process with the LinkButton onclick event, as follows:

Client: <asp:FileUpload ID= "fuPhoto" onchange= "javascript:__doPostBack(‘lbUploadPhoto‘,‘‘)" runat= "server" ToolTip= "选择图片" /> <asp:LinkButton ID= "lbUploadPhoto" runat= "server" OnClick= "lbUploadPhoto_Click" ></asp:LinkButton> Background code: //自动上传事件 protected void lbUploadPhoto_Click( object sender, EventArgs e) { fileUpload(); } //从控件上传文件 public void fileUpload() { if (fuPhoto.PostedFile != null && fuPhoto.PostedFile.ContentLength > 0) { string ext = System.IO.Path.GetExtension(fuPhoto.PostedFile.FileName).ToLower(); if (ext != ".jpg" && ext != ".jepg" && ext != ".bmp" && ext != ".gif" ) { return ; } string filename = "Image_" + DateTime.Now.ToString( "yyyyMMddHHmmss" ) + ext; string path = "./UploadPhoto/" + filename; fuPhoto.PostedFile.SaveAs(Server.MapPath(path)); Response.Redirect( "ImageCut.aspx?Picurl=" + Server.UrlEncode(path)); } else { //do some thing; } }

Asp. NET enables FileUpload controls to support the resolution of the automatic upload feature