C#调用C++的DLL函数另一则(delegate) z

使用DLLImport进行导入函数的事. C#调用C++的函数其实不止这一种方法, 还有一种方法是用delegate申明函数委托进行调用,这种方法略显麻烦,但是可以进行回调并应用指针.

在C#中,首先先要定义一个类,用来把DLL中函数地址转换成委托:

public class DLLWrapper
{
///<summary>
/// API LoadLibrary
///</summary>
[DllImport("Kernel32")]
public static extern int LoadLibrary(String funcname);

///<summary>
/// API GetProcAddress
///</summary>
[DllImport("Kernel32")]
public static extern int GetProcAddress(int handle, String funcname);

///<summary>
/// API FreeLibrary
///</summary>
[DllImport("Kernel32")]
public static extern int FreeLibrary(int handle);

///<summary>
///通过非托管函数名转换为对应的委托, by jingzhongrong
///</summary>
///<param name="dllModule">Get DLL handle by LoadLibrary</param>
///<param name="functionName">Unmanaged function name</param>
///<param name="t">ManageR type对应的委托类型</param>
///<returns>委托实例，可强制转换为适当的委托类型</returns>
public static Delegate GetFunctionAddress(int dllModule, string functionName, Type t)
{
int address = GetProcAddress(dllModule, functionName);
if (address == 0)
return null;
else
return Marshal.GetDelegateForFunctionPointer(new IntPtr(address), t);
}

///<summary>
///将表示函数地址的IntPtr实例转换成对应的委托, by jingzhongrong
///</summary>
public static Delegate GetDelegateFromIntPtr(IntPtr address, Type t)
{
if (address == IntPtr.Zero)
return null;
else
return Marshal.GetDelegateForFunctionPointer(address, t);
}

///<summary>
///将表示函数地址的int转换成对应的委托，by jingzhongrong
///</summary>
public static Delegate GetDelegateFromIntPtr(int address, Type t)
{
if (address == 0)
return null;
else
return Marshal.GetDelegateForFunctionPointer(new IntPtr(address), t);
}
}

然后, 用delegate声明函数:

delegate void _amDBRSetThermoModel(int mid, ref int errid);

再然后, 自己写个private的函数封装DLL中的函数, hModule()函数的作用是取得DLL的地址,用在多个输出函数中

private int hModule()
{
int _hModule = DLLWrapper.LoadLibrary(DLLPATH);
if (_hModule == 0)
{
return 0;
}
return _hModule;
}

private void amDBRInitialize()
{
try
{
_amDBRInitialize amf = (_amDBRInitialize)DLLWrapper.GetFunctionAddress(hModule(), "amDBRInitialize", typeof(_amDBRInitialize));
amf();
}
catch (Exception e)
{
throw e;
}
}