FileUpload加载图片上传之前预览的问题

cxdnnew 2017-12-21 12:22:46

FileUpload加载图片上传之前预览的问题，下面的代码是 VS2010做的，为什么显示不了图片啊？请指教
<%@ Page Title="主页" Language="C#" MasterPageFile="~/Site.master" AutoEventWireup="true" CodeBehind="Default.aspx.cs" Inherits="WebImagePro._Default" %>
<asp:Content ID="HeaderContent" runat="server" ContentPlaceHolderID="HeadContent"></asp:Content>
<asp:Content ID="BodyContent" runat="server" ContentPlaceHolderID="MainContent">

<asp:Image ID="Image1" runat="server" Height="554px" Width="598px" />
<br />
<asp:FileUpload ID="FileUpload1" runat="server" onchange="PreviewImage(this,'Image1')" Width="220px" />

<asp:Label ID="Label1" runat="server" Text="" Style="color: Red"></asp:Label>
<asp:Button ID="ButtonLoad" runat="server" Height="21px" Text="输入图像" Width="53px" onclick="ButtonLoad_Click" />
<script language="javascript" type="text/javascript">
function PreviewImage(fileObj, imgPreviewId)
{
if (fileObj.files)
{
if (window.FileReader) {
var reader = new FileReader();
reader.onload = function (e) {
document.getElementById(imgPreviewId).setAttribute("src", e.target.result);
}
reader.readAsDataURL(fileObj.files[0]);
}
}
else
{
document.getElementById(imgPreviewId).setAttribute("src", fileObj.value);
}
}
</script>
</asp:Content>

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