<ext:Button ID="DownLoad" runat="server" Text="下载二维码" Width="120" Height="35" ???AutoPostBack="false"> ???<DirectEvents> ???????<Click OnEvent="DownLoad_Click"> ???????</Click> ???</DirectEvents></ext:Button>
protected void DownLoad_Click(object sender, DirectEventArgs e){ ???WriteFile("/images/1.jpg");}public void WriteFile(string filePath){ ???try ???{ ???????string _pre_path = filePath; ???????filePath = Server.MapPath(filePath); ???????if (File.Exists(filePath)) ???????{ ???????????FileInfo info = new FileInfo(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(); ???}}如果使用以上代码会报200错误，但是在Button上加一个就能正常运行，很莫名其妙，1.2版本。
<ext:FileUploadField ID="fileUpload" runat="server" ButtonOnly="true" EmptyText="上传LOGO" ???ButtonText=""></ext:FileUploadField>
<ext:Button ID="DownLoad" runat="server" Text="下载二维码" Width="120" Height="35" ???AutoPostBack="false"> ???<DirectEvents> ???????<Click OnEvent="DownLoad_Click"> ???????</Click> ???</DirectEvents></ext:Button>
Extjs.net Button点击下载jpg图片
原文地址：https://www.cnblogs.com/zhaogaojian/p/9287127.html