从非托管DLL调用函数

本文关键字：调用 函数 DLL | 更新日期: 2023-09-27 18:10:24

我有一个具有以下功能的非托管DLL:

ReadLatch( HANDLE cyHandle,
                LPWORD  lpLatch);

WriteLatch(HANDLE cyHandle,
                WORD    mask,
                WORD    latch);

GetPartNumber(HANDLE cyHandle,
                   LPBYTE   lpbPartNum);
 GetDeviceProductString(HANDLE  cyHandle,
                            LPVOID  lpProduct,
                            LPBYTE  lpbLength,
                            BOOL    bConvertToASCII = TRUE
                            );

GetDeviceSerialNumber(HANDLE   cyHandle,
                           LPVOID   lpSerialNumber,
                           LPBYTE   lpbLength,
                           BOOL     bConvertToASCII = TRUE
                           );

 GetDeviceInterfaceString(HANDLE    cyHandle,
                              LPVOID lpInterfaceString,
                              LPBYTE lpbLength,
                              BOOL bConvertToASCII);

我正在尝试导入这些函数，但没有找到正确的数据类型:

[DllImportAttribute("runtime.dll", EntryPoint = "ReadLatch", CallingConvention =     CallingConvention.Cdecl)]
    static extern int ReadLatch(HANDLE cyHandle, [MarshalAs(UnmanagedType. ??????)] ?????? lpLatch);
    [DllImportAttribute("runtime.dll", EntryPoint = "WriteLatch", CallingConvention = CallingConvention.Cdecl)]
    static extern int WriteLatch(HANDLE cyHandle,
                WORD mask,
                WORD latch);
    [DllImportAttribute("runtime.dll", EntryPoint = "GetPartNumber", CallingConvention = CallingConvention.Cdecl)]
    static extern int GetPartNumber(HANDLE cyHandle,
                   LPBYTE lpbPartNum);
    [DllImportAttribute("runtime.dll", EntryPoint = "GetDeviceProductString", CallingConvention = CallingConvention.Cdecl)]
    static extern int GetDeviceProductString(HANDLE cyHandle,
                            LPVOID lpProduct,
                            LPBYTE lpbLength,
                            BOOL bConvertToASCII = TRUE
                            );
    [DllImportAttribute("runtime.dll", EntryPoint = "GetDeviceSerialNumber", CallingConvention = CallingConvention.Cdecl)]
    static extern int GetDeviceSerialNumber(HANDLE cyHandle,
                           LPVOID lpSerialNumber,
                           LPBYTE lpbLength,
                           BOOL bConvertToASCII = TRUE
                           );
    [DllImportAttribute("runtime.dll", EntryPoint = "GetDeviceInterfaceString", CallingConvention = CallingConvention.Cdecl)]
    static extern int GetDeviceInterfaceString(HANDLE cyHandle,
                              LPVOID lpInterfaceString,
                              LPBYTE lpbLength,
                              BOOL bConvertToASCII);

我在哪里可以找到关于如何表示HANDLE、LPWORD和其他函数的信息，以便我可以调用这些函数?

从非托管DLL调用函数

非托管类型及其托管对应类型:

  • HANDLE通常用IntPtr表示。
  • WORD - UInt16

对于其他的，我们可能需要更多地了解它们是如何使用的。

希望你的API有一些附带的文档来解释参数的作用，因为其中一些不是很明显。

对于这个函数，我们可以做一些假设: 
ReadLatch(HANDLE cyHandle, LPWORD  lpLatch);

假设lpLatch实际上是一个"out"参数(并且您的返回类型是int):

[DllImportAttribute("runtime.dll", EntryPoint = "ReadLatch", CallingConvention = CallingConvention.Cdecl)]
static extern int ReadLatch(IntPtr cyHandle, out UInt16 lpLatch);
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