如何使用結構指針導入非託管dll？

Question

我可以通過DllImport的常用功能，但未能導入這種類型，下面是DLL頭文件。

typedef struct 
{ 
    VOID (* API_GetUID)(CHAR *pData, DWORD DataLen); 

    DWORD (* API_GetChipType)(); 

} API_FUNCTION_STRUCT, *API_FUNCTION_STRUCT; 

extern VOID WINAPI GetAPIObject(API_FUNCTION_STRUCT *pApiFunc); 

我不能在C＃中編寫正確的結構。

public struct test 
    { 
     IntPtr API_GetUID(IntPtr pData, int DataLen); 
     IntPtr  API_GetChipType(); 
    } 

[DllImport(@"GDevice.dll")] 
public static extern void GetAPIObject(ref test test_a); 

更新：

public struct test 
{ 
delegate void API_GetUID(IntPtr pData, int DataLen); 
delegate void API_GetChipType(); 
} 

Answer 1

您可能需要使用Marshal.GetDelegateForFunctionPointer function

這需要一個IntPtr指向一個本地方法，讓您回一個代表，你可以調用。

public struct test 
{ 
    IntPtr API_GetUID; 
    IntPtr API_GetChipType; 
} 

[DllImport(@"GDevice.dll")] 
public static extern void GetAPIObject(ref test test_a); 

delegate void GetUID_Delegate(IntPtr pData, uint dataLen); 
delegate uint GetChipType_Delegate(); 

test a = new test(); 
GetAPIObject(ref a); 

GetUID_Delegate getUID = Marshal.GetDelegateForFunctionPointer<GetUID_Delegate>(a.API_GetUID); 
GetChipType_Delegate getChipType = Marshal.GetDelegateForFunctionPointer<GetChipType_Delegate>(a.API_GetChipType); 

uint chipType = getChipType(); 

編輯

或者使用UnmanagedFunctionPointerAttribute。

public struct test 
{ 
    GetUID_Delegate API_GetUID; 
    GetChipType_Delegate API_GetChipType; 

    [UnmanagedFunctionPointer(CallingConvention.Cdecl)] 
    delegate void GetUID_Delegate(IntPtr pData, uint dataLen); 
    [UnmanagedFunctionPointer(CallingConvention.Cdecl)] 
    delegate uint GetChipType_Delegate(); 
} 

[DllImport(@"GDevice.dll")] 
public static extern void GetAPIObject(ref test test_a); 

test a = new test(); 
GetAPIObject(ref a); 

uint chipType = a.API_GetChipType();