c# - 如何在 ASP.NET 中上传图像文件而不进行任何回发

Question

我正在使用 <asp:FileUpload> 上传文件和 <asp:button>控件，但我想在没有回发的情况下进行。单击按钮时，我执行以下代码。

protected void btnUpload_Click(object sender, EventArgs e)
{
    string strFileName = Path.GetFileName(FileUpload1.FileName);  //fileupload1 is the <asp:fileupload ID
    FileUpload1.SaveAs(Server.MapPath("~/UploadFile/" + strFileName + ""));
    imgUpload.ImageUrl = "../UploadFile/" + strFileName + "";  //imgupload is the <img ID on which I am showing the image after upload
    imgUpload.Visible = true;
}

上传文件后，我在我的项目解决方案中显示指定文件夹中保存的图像，但是在单击上传按钮时整个页面都会加载，我不希望在单击上传按钮时回发。

Answer 1

just add the script

    <script language="javascript">
        function Change(obj) {
             __doPostBack("<%= btnUpload.ClientID %>", "");
        }

      </script>


Call the script in your button click event like this 
<pre>
onchange="Change(this);"
</pre>   

Your image control added in the update panel with contentTemplate 

    <asp:FileUpload ID="imgFileUploader" runat="server"   />
             <asp:Button ID="btnUpload" runat="server"  
         Text="Upload" onclick="btnUpload_Click" onchange="Change(this);" />
      <br />
        <br />
     <asp:ScriptManager ID="ScriptManager1" runat="server">
     </asp:ScriptManager>
  &nbsp;<asp:UpdatePanel ID="UpdatePanel1" runat="server">
            <ContentTemplate>    
               <img id="imgOrginal" runat="server" style="height: 200px; width: 200px;" />
              </ContentTemplate>
      </asp:UpdatePanel>

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