C＃編組C結構

Question

我有這個CC＃代碼工作：

.H

typedef struct { 

    float a; 
    float b; 

} MyStruct; 

extern MyStruct mystruct; 

__declspec(dllexport) void GetMyStruct (MyStruct* s); 
__declspec(dllexport) void SetMyStruct (MyStruct* s); 

.C

MyStruct mystruct; 

    void GetMyStruct (MyStruct* s) 
    { 

     *s = AeroLink_IOPkt; 
    } 

    void SetMyStruct (MyStruct* s) 
    { 

     AeroLink_IOPkt = *s; 
    } 

void test() 
{ 
    // some code that update element in struct 
    // mystruct.a = 0.4; 
    // mystruct.a = 0.1; 
} 

的.cs

public struct MyStruct 
{ 

    public float a; 
    public float b; 

} 


[DllImport(DLL_NAME, EntryPoint = "GetMyStruct")] 
protected static extern void GetMyStruct(ref MyStruct s); 

[DllImport(DLL_NAME, EntryPoint = "SetMyStruct")] 
protected static extern void SetMyStruct(ref MyStruct s); 

這樣，每次我需要將數據從C＃設置爲C時，我必須調用void SetMyStruct，反之亦然，如果我想從C（從無效測試更新）到C＃的數據，我必須調用GetMyStruct。我必須每秒做50次。

是否有避免每次撥打SetMyStruct和GetMyStruct的方法？我希望一次使用SetMyStruct，然後將所有更改反映出來。我不知道這是否可能。

Answer 1

你可以用unsafe和指針來做到這一點。

您需要編譯啓用「不安全」的C＃程序。

編輯：一種更好的方式：

添加以下函數庫：

__declspec(dllexport) void GetMyStructRef (MyStruct** s); 
void GetMyStructRef(MyStruct** s) 
{ 
    *s = &mystruct; 
} 

在C＃：

[DllImport(DLL_NAME, EntryPoint = "GetMyStructRef")] 
protected static extern void GetMyStructRef(ref MyStruct* s); 

MyStruct* data; 
GetMyStructRef(ref data); 
Console.WriteLine($"{data->a} {data->b}"); 

老答案：

unsafe class MyClass : IDisposable 
{ 
    [DllImport(DLL_NAME, EntryPoint = "GetMyStruct")] 
    protected static extern void GetMyStruct(MyStruct* s); 

    [DllImport(DLL_NAME, EntryPoint = "SetMyStruct")] 
    protected static extern void SetMyStruct(MyStruct* s); 

    GCHandle handle; 
    MyStruct* structRef; 

    public void MyClass() 
    { 
     //we need to get a pinned reference to your struct 
     handle = GCHandle.Alloc(new MyStruct(), GCHandleType.Pinned); 
     structRef = (MyStruct*)handle.AddrOfPinnedObject().ToPointer(); 

     SetMyStruct(structRef); 
    } 

    public void Dispose() 
    { 
     //We need to free the handle to release memory 
     //GC will not collect it without this 
     handle.Free(); 
    } 
}