C++方法调用问题,高手请进

[Jack2013tong]

//获取排行
int UMWEBCLIENT GetPlayerList(const int maxrows, int* rows, tagPlayerInfo** ppPlayerInfo);
这是c++写的一个方法,um_web_client.dll是供调用的dll
ppPlayerInfo 是结构体
// public struct tagPlayerInfo
// {
// public int id;
// public char[] PlayerName;
// public int Country;
// public int OfficerRace;
// public int Level;
// public int MilitaryRank;
// public int Money;
// public int ResourceCount;
// public int CityCount;
// public int GeneralCount;
// public int Credit;
// };
[DllImport("um_web_client.dll")]
请问在c#中如何声明及调用这个方法,请高手们给出具体的写法,谢谢!

[tweeger]

lz可以做如下尝试：
1、在C#中使用class来描述tagPlayerInfo结构；
2、在C#中描述GetPlayerList方法时使用类似(..., ref tagPlayerInfo ppPlayerInfo)的方法；
3、在调用GetPlayerList方法时传入tagPlayerInfo对象的引用。

[龙宜坡]

public struct tagPlayerInfo
{
    public int id;
    public string PlayerName;
    public int Country;
    public int OfficerRace;
    public int Level;
    public int MilitaryRank;
    public int Money;
    public int ResourceCount;
    public int CityCount;
    public int GeneralCount;
    public int Credit;
};
[DllImport("um_web_client.dll")]
public static extern int GetPlayerList(int maxrows, ref int rows,out tagPlayerInfo[] ppPlayerInfo);

[宝_爸]

two level指针tagPlayerInfo** ppPlayerInfo

估计够戗

可以参考

Passing Structures
http://msdn.microsoft.com/en-us/library/awbckfbz.aspx

[ljyxr]

不会 帮顶

[tweeger]

参照MSDN有如下写法：
[DllImport("um_web_client.dll", EntryPoint = "GetPlayerList")]
private static extern int GetPlayerList(int maxrows, ref int rows, IntPtr ppPlayerInfo);

tagPlayerInfo test = new tagPlayerInfo();
...
// Initialize unmanged memory to hold the struct.
IntPtr pointer = Marshal.AllocHGlobal(Marshal.SizeOf(test));
try
{
// Copy the struct to unmanaged memory.
Marshal.StructureToPtr(test, pointer, false);

IntPtr[] pointArray = new IntPtr[1];
pointArray[0] = pointer;

IntPtr addrPointer = Marshal.UnsafeAddrOfPinnedArrayElement(pointArray, 0);
code = GetPlayerList(addrPointer);

// Set this tagPlayerInfo to the value of the
// tagPlayerInfo in unmanaged memory.
test = (tagPlayerInfo)Marshal.PtrToStructure(pointer, typeof(tagPlayerInfo));
}
finally
{
// Free the unmanaged memory.
Marshal.FreeHGlobal(pointer);
}

[Jack2013tong]

[DllImport("um_web_client.dll")]
public static extern int GetPlayerListCs(int maxrows, out int rows, out IntPtr playerlist);

[DllImport("um_web_client.dll")]
public static extern int GetPlayerListCs(int maxrows, out int rows, tagPlayerInfoOutEx** playerlist);

这样声明可以,测试通过

[Jack2013tong]

还没有得到答案,哪位高手帮下忙?

[zjh222]

互操作是NET最麻烦的操作,为什么微软不把Win Api包装完整呀??

[xiaxy1]

菜鸟帮顶

[龙宜坡]

public struct tagPlayerInfo
        {
            public int id;
            public string PlayerName;
            public int Country;
            public int OfficerRace;
            public int Level;
            public int MilitaryRank;
            public int Money;
            public int ResourceCount;
            public int CityCount;
            public int GeneralCount;
            public int Credit;
        };
        [DllImport("um_web_client.dll")]
        public static extern int GetPlayerList(int maxrows, ref int rows, out tagPlayerInfo[] ppPlayerInfo);
        
        //使用
        public void SomeMethod()
        {
            int maxrows=10, rows = 0;
            tagPlayerInfo[] ppPlayerInfo;
            GetPlayerList(maxrows, ref rows, out ppPlayerInfo);
        }

看这样行不？

[Jack2013tong]

不行,out ppPlayerInfo出来的ppPlayerInfo为null,

[龙宜坡]

        public struct tagPlayerInfo
        {
            public int id;
            public string PlayerName;
            public int Country;
            public int OfficerRace;
            public int Level;
            public int MilitaryRank;
            public int Money;
            public int ResourceCount;
            public int CityCount;
            public int GeneralCount;
            public int Credit;
        };
        [DllImport("um_web_client.dll")]
        public static extern int GetPlayerList(int maxrows, ref int rows, [MarshalAs(UnmanagedType.LPStruct)]tagPlayerInfo ppPlayerInfo);

        //使用
        public void SomeMethod()
        {
            int maxrows = 10, rows = 0;
            tagPlayerInfo ppPlayerInfo=new tagPlayerInfo();
            GetPlayerList(maxrows, ref rows, ppPlayerInfo);
            //ppPlayerInfo.id
        }

[Jack2013tong]

GetPlayerList(maxrows, ref rows, ppPlayerInfo);
//ppPlayerInfo.id
你这样是取得一个结构体的信息?怎么取出下一个呢?原方法里是一个结构体的数据集,有多个,请问怎么写?

[tweeger]

如果可以使用unsafe的话，可以使用如下的写法：
1、测试dll，用来模拟um_web_client.dll
struct tagPlayerInfo
{
public:
int id;
int Money;
};

extern "C" _declspec(dllexport) int GetPlayerList(tagPlayerInfo** ppPlayerInfo)
{
if(ppPlayerInfo != NULL && *ppPlayerInfo != NULL)
{
(*ppPlayerInfo)->id = 1;
(*ppPlayerInfo)->Money = 1;

MessageBox(NULL, (LPCWSTR)("Successed"), (LPCWSTR)("GetPlayerList"), MB_OK);

return 1;
}

return 0;
}
2、C#中调用
public struct tagPlayerInfo
{
public int id;
public int Money;
}

[DllImport("um_web_client.dll", EntryPoint = "GetPlayerList")]
private static extern unsafe int GetPlayerList(tagPlayerInfo** ppPlayerInfo);

private void button3_Click(object sender, EventArgs e)
{
tagPlayerInfo test = new tagPlayerInfo();
test.id = 0;
test.Money = 0;

int code = 0;
unsafe
{
tagPlayerInfo* tagPoint = &test;
code = GetPlayerList(&tagPoint);
}
Console.WriteLine(code);
}

经过测试可以实现lz的需求。

[龙宜坡]

unsafe

也许可以，但最好不这么处理！