相关疑难解决方法(0)

我有一个Visual Studio 2008 C#.NET 3.5应用程序P/Invokes一个接受文件句柄作为参数的本机方法.最初,我只是使用FileStream.SafeFileHandle.DangerousGetHandle()来获取文件句柄.但是,在启用FX COP之后,我收到了CA2001的警告.因此,经过一番研究后,我发现了"约束执行区域".这对我来说是新的,我还没有看到很多关于它的信息.我希望有经验的人可以看看并验证我是否已正确完成此操作.

class MyClass
{
    public static bool Write(string filename)
    {
        using (var fs = new System.IO.FileStream(filename, 
            System.IO.FileMode.Create, 
            System.IO.FileAccess.Write, 
            System.IO.FileShare.None))
        {
            bool got_handle;
            bool result;

            System.Runtime.CompilerServices.RuntimeHelpers.PrepareConstrainedRegions();
            try { }
            finally
            {
                fs.SafeFileHandle.DangerousAddRef(ref got_handle);
                result = NativeMethods.Foo(fs.SafeFileHandle.DangerousGetHandle());
                if (got_handle)
                    fs.SafeFileHandle.DangerousRelease();   
            }

            return result;
        }
    }
}

internal sealed class NativeMethods
{
    [DllImport("mylib.dll",
        EntryPoint = "Foo",
        CallingConvention = CallingConvention.StdCall,
        CharSet = CharSet.Unicode,
        ExactSpelling = true, 
        SetLastError = true)]
    public static extern bool Foo(IntPtr hFile);
}

谢谢,PaulH