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Windows电话“ System.IO”的VB silverlight

[英]VB silverlight for windows phone “System.IO”

原文 2012-05-12 15:56:24 9 1 .net/ windows/ vb.net/ windows-phone-7.1

hello i am having an error : "Attempt to access the method failed: System.IO.File.Exists(System.String)" 你好，我遇到一个错误：“尝试访问该方法失败：System.IO.File.Exists（System.String）”

i have to note that this line is having an external url 我必须注意，这行有一个外部网址

If File.Exists("http://www.demo.com/demo.xml") Then blah end if

during my first try it worked but now it seems bugy :S it does not make sense ! 在我的第一次尝试中，它奏效了，但现在似乎有问题：S这没有任何意义！

1 个解决方案

It sounds like you should be making a web request (eg with WebClient ) instead. 听起来您应该发出Web请求（例如，使用WebClient ）。

You're using File.Exists and passing it a URL. 您正在使用File.Exists并将其传递给URL。 File.Exists is meant to be for file system paths. File.Exists用于文件系统路径。 In fact, you're not meant to call File.Exists at all on Windows Phone 7. When in doubt, consult the documentation : 实际上，您根本File.Exists在Windows Phone 7上调用File.Exists 。如有疑问，请查阅文档：

This member has a SecurityCriticalAttribute attribute on Silverlight for Windows Phone, because the attribute was present in Silverlight 3. This attribute restricts this member to internal use. 该成员在Silverlight for Windows Phone上具有SecurityCriticalAttribute属性，因为该属性存在于Silverlight 3中。此属性将其限制为内部使用。 Application code that uses this member throws a MethodAccessException. 使用此成员的应用程序代码将引发MethodAccessException。