在Update Panel 控件里面添加 File Upload 控件 上传文件

<asp:UpdatePanel ID="UpdatePanel1" runat="server" UpdateMode="Conditional">
<ContentTemplate>
<asp:FileUpload ID="fileUploadImage" runat="server"></asp:FileUpload>
<asp:Button ID="btnUpload" runat="server" Text="Upload Image" OnClick="btnUpload_Click" />
<br />
<asp:Button ID="btnProcessData" runat="server" Text="Process Data" OnClick="btnProcessData_Click" /><br />
<asp:Label ID="lblMessage" runat="server" Text="Image uploaded successfully." Visible="false"></asp:Label><br />
<asp:UpdateProgress ID="UpdateProgress1" runat="server" AssociatedUpdatePanelID="UpdatePanel1">
<ProgressTemplate>
Please wait image is getting uploaded....
</ProgressTemplate>
</asp:UpdateProgress>
<br />
<b>Please view the below image uploaded</b><br />
<asp:Image ID="img" runat="server" Width="100" Height="100" ImageAlign="Middle" />
</ContentTemplate>
<Triggers>
<asp:PostBackTrigger ControlID="btnUpload"  />
<asp:AsyncPostBackTrigger ControlID="btnProcessData" />
</Triggers>
</asp:UpdatePanel>