空格变%20,该怎么处理

空格变%20

C# code

FileUpload1.Attributes.Add("onchange", @"document.getElementById('imgPhoto').src=document.getElementById('FileUpload1').value.unescape();");

C# code

FileUpload1.Attributes.Add("onchange", @"document.getElementById('imgPhoto').src=unescape(document.getElementById('FileUpload1').value);");
[解决办法]
C# code
Microsoft.JScript.GlobalObject.unescape(object @string)
[解决办法]
urlencode
urldecode