C# EntryPointNotFoundException在DLL 'kernel32.dll‘中找不到名为'SetDllDirectory’的入口点

Question

我正在尝试使用kernal32.dll中的几个函数。但是，当我的应用程序试图调用第一个函数时，它会抛出一个EntryPointNotFoundException Unable to find an entry point named 'SetDllDirectory' in DLL 'kernel32.dll'.

public class MyClass
{
    /// <summary>
    /// Use to interface to kernel32.dll for dynamic loading of similar DLLs.
    /// </summary>
    internal static class UnsafeNativeMethods
    {
        [DllImport("kernel32.dll", CharSet = CharSet.Ansi, ExactSpelling = true, SetLastError = true)]
        internal static extern IntPtr LoadLibrary(string lpFileName);

        [DllImport("kernel32.dll", CharSet = CharSet.Ansi, ExactSpelling = true, SetLastError = true)]
        internal static extern bool SetDllDirectory(string lpPathName);

        [DllImport("kernel32.dll", CharSet = CharSet.Ansi, ExactSpelling = true, SetLastError = true)]
        internal static extern IntPtr GetProcAddress(IntPtr hModule, string procName);
    }

    private void MyFunc()
    {
        if (UnsafeNativeMethods.SetDllDirectory(_location) == false) // <-- Exception thrown here.
        {
            throw new FileNotFoundException(_location);
        }

        /* Some code. */

        _dllHandle = UnsafeNativeMethods.LoadLibrary(_fullPath);

        /* Some more code. */

        _fptr = UnsafeNativeMethods.GetProcAddress(_dllHandle, _procName);

        /* Yet even more code. */
    }
}

任何关于我做错了什么以及如何让它工作的想法都将不胜感激。谢谢。

Answer 1

您必须删除ExactSpelling属性。该函数的真实名称是SetDllDirectoryW。我也推荐你使用CharSet.Auto，使用Ansi是一个有损的转换，可能会导致一些微妙的问题。在XP SP1之前的任何Windows版本中都不提供导出。

Answer 2

我不太了解DllImport，但是在我的机器上删除ExactSpelling属性就可以了。