C＃：一个用于多个声明的属性（DLLImport）

Question

我正在使用该[DLLImport]属性访问.NET代码中的一堆C ++函数。现在，我通过以下方式拥有所有功能：

const string DLL_Path = "path\\to\\my\\dll.dll";

[DllImport(DLL_Path, 
    CallingConvention = CallingConvention.StdCall, 
    CharSet = CharSet.Ansi)] 
public static extern int MyFunction1();

[DllImport(DLL_Path, 
    CallingConvention = CallingConvention.StdCall, 
    CharSet = CharSet.Ansi)]
public static extern ErrorCode MyFunction2(int id);

[DllImport(DLL_Path, 
    CallingConvention = CallingConvention.StdCall, 
    CharSet = CharSet.Ansi)]
public static extern ErrorCode MyFunction3(string server, byte timeout, 
    ref int connection_id, ref DeviceInfo pInfos);

[DllImport(DLL_Path, 
    CallingConvention = CallingConvention.StdCall,
    CharSet = CharSet.Ansi)]
public static extern ErrorCode MyFunction4([MarshalAs(UnmanagedType.LPArray)] byte[] pVersion, 
    ref int psize);

[DllImport(DLL_Path, 
    CallingConvention = CallingConvention.StdCall, 
    CharSet = CharSet.Ansi)]
public static extern ErrorCode MyFunction5(int errorcode, 
    [MarshalAs(UnmanagedType.LPTStr)] string pmsg, ref int psize);

这真是让人不悦：重复属性似乎效率低下，并且破坏了函数原型的可读性。特别是因为我要导入20或30个函数。

我想知道我是否[DllImport(DLL_Path, CallingConvention = CallingConvention.StdCall, CharSet = CharSet.Ansi)]只能在某个地方拥有该零件一次，并且可以更清楚地识别出函数定义，例如伪代码：

const string DLL_Path = "path\\to\\my\\dll.dll";
// some code defining a section which tells that the next functions are DLLImport
[DllImport(DLL_Path, CallingConvention = CallingConvention.StdCall, CharSet = CharSet.Ansi)] 
{
    public static extern int MyFunction1();

    public static extern ErrorCode MyFunction2(int id);

    public static extern ErrorCode MyFunction3(string server, byte timeout, ref int connection_id, ref DeviceInfo pInfos);

    public static extern ErrorCode MyFunction4([MarshalAs(UnmanagedType.LPArray)] byte[] pVersion, ref int psize);

    public static extern ErrorCode MyFunction5(int errorcode, [MarshalAs(UnmanagedType.LPTStr)] string pmsg, ref int psize);
}

这可能吗？
我在SO中发现了这个问题：缩短C＃中的DllImport数量？但是它建议通过LoadLibrary和动态加载函数GetProcAddress，但我觉得可读性较差。

Answer 1

不，无法将Attributes简化为单个声明。您需要将Attribute应用于所有方法。

但你至少可以缩短您的属性声明来[DllImport(DLL_Path)]，因为你指定的价值观CallingConvention和CharSet是一样的默认值。