Extjs.net button click to download JPG image

<ext:button id="DownLoad"runat="Server"text="download QR code"Width=" -"height=" *"AutoPostBack="false"> <DirectEvents> <click onevent="Download_click"> </Click> </DirectEvents></ext:Button>

protected void Download_click (object  sender, Directeventargs e) {    WriteFile ("/images/1.jpg ");}

 Public voidWriteFile (stringFilePath) {    Try    {        string_pre_path =FilePath; FilePath=Server.MapPath (FilePath); if(File.exists (FilePath)) {FileInfo Info=NewFileInfo (FilePath);            Response.Clear ();            Response.clearcontent ();            Response.ClearHeaders (); Response.AddHeader ("content-disposition","attachment;filename="+System.IO.Path.GetFileName (FilePath)); Response.AddHeader ("Content-length", Info.            Length.tostring ()); Response.AddHeader ("content-transfer-encoding","binary"); Response.ContentType="Application/octet-stream"; Response.ContentEncoding= System.Text.Encoding.GetEncoding ("gb2312"); Response.WriteFile (info.            FullName);            Response.Flush ();        Response.End (); }    }    Catch(System.Threading.ThreadAbortException ex0) {}Catch(Exception ex1) {}finally{HttpContext.Current.Response.Close (); }}

If using the above code will be reported 200 error, but on the button plus one will be able to run normally, very inexplicable, 1.2 version.

<ext:fileuploadfield id="fileUpload" runat="server " buttononly="true" emptytext=" upload logo"     ButtonText=""></ext:FileUploadField>

<ext:button id= "DownLoad" runat= "server" text= "download QR Code" width= "" height= "+" autopostback= "    false" >    <DirectEvents>        <click onevent= "Download_click" >        </Click>    </directevents ></ext:Button>

Extjs.net button click to download JPG image