将 C dll 和方法导入 c#答案

【问题标题】：importing a C dll and method into c#将 C dll 和方法导入 c#
【发布时间】：2013-11-10 22:39:49
【问题描述】：

我在让 C 方法在 C# 中工作时遇到问题 - 该东西在 C 中编译并运行良好，返回设备 ID 的正确结果 - 但在 windows 中，该函数似乎无法正确构建字符串。以下是使用 C 语言工作的源代码，来自 oblita.com 上的 interception.dll 示例：

int main()
{
using namespace std;

InterceptionContext context;
InterceptionDevice device;
InterceptionStroke stroke;

wchar_t hardware_id[500];

raise_process_priority();

context = interception_create_context();

interception_set_filter(context, interception_is_keyboard, INTERCEPTION_FILTER_KEY_DOWN | INTERCEPTION_FILTER_KEY_UP);
interception_set_filter(context, interception_is_mouse, INTERCEPTION_FILTER_MOUSE_LEFT_BUTTON_DOWN);

while(interception_receive(context, device = interception_wait(context), &stroke, 1) > 0)
{
    if(interception_is_keyboard(device))
    {
        InterceptionKeyStroke &keystroke = *(InterceptionKeyStroke *) &stroke;

        if(keystroke.code == SCANCODE_ESC) break;
    }

    size_t length = interception_get_hardware_id(context, device, hardware_id, sizeof(hardware_id));

    if(length > 0 && length < sizeof(hardware_id))
        wcout << hardware_id << endl;

    interception_send(context, device, &stroke, 1);
}

interception_destroy_context(context);

return 0;

现在，我已经在 C# 中导入了 DLL，它应该正确涵盖所有变量转换：

    [DllImport("interception.dll", EntryPoint = "interception_get_hardware_id", CallingConvention = CallingConvention.Cdecl)]
    public static extern int GetHardwareID(IntPtr context, int device, ref StringBuilder idbuffer, uint buffer_size);

这是我试图在 C# 中获取设备 ID 的代码：

     {
        IntPtr context;
        int device;
        Interception.Stroke stroke = new Interception.Stroke();

        context = Interception.CreateContext();
        Interception.SetFilter(context, Interception.IsKeyboard, Interception.Filter.All);
        StringBuilder hardwareID = new StringBuilder();

        while (Interception.Receive(context, device = Interception.Wait(context), ref stroke, 1) > 0)
        {

            int hardwareID_length = Interception.GetHardwareID(context, device, ref hardwareID, Convert.ToUInt32(hardwareID.Length));
            if (hardwareID_length > 0 && hardwareID_length < Convert.ToUInt32(hardwareID.Length))
            Console.WriteLine("ID result: ", hardwareID);

            Console.WriteLine("SCAN CODE: {0}/{1}", stroke.key.code, stroke.key.state);

            if (stroke.key.code == ScanCode.X)
            {
                stroke.key.code = ScanCode.Y;
            }
            Interception.Send(context, device, ref stroke, 1);

            // Hitting escape terminates the program
            if (stroke.key.code == ScanCode.Escape)
            {
                break;
            }
        }

        Interception.DestroyContext(context);
    }
}

if 语句中的块永远不会触发 - 它没有正确打印 ID，我认为这意味着 stringbuilder 没有像 C 中的 wchar_t 那样正确填充。值为 0，这意味着它从未被喂过正确的信息由指针，对不对？我能做些什么来解决这个问题？非常感谢任何帮助。

应该注意的是，扫描码可以正常工作 - 它可以检测击键，甚至按预期将 x 替换为 y。

【问题讨论】：

标签： c# c pointers dll

【解决方案1】：

由于我自己的挖掘和大量的试验和错误，以下是如何让它发挥作用：

{
[DllImport("interception.dll", EntryPoint = "interception_get_hardware_id", CallingConvention = CallingConvention.Cdecl)]
    public static unsafe extern int GetHardwareID(IntPtr context, int device, out void* idbuffer, uint buffer_size);

//Note the call is unsafe - because we're using the void* pointer.

{(inside an unsafe block of code)

void* hardwareID;
//call function as follows:
int result = Interception.GetHardwareID(context, device, out hardwareID, 5000);
//i use 5000 because it works. i'm sure there's better ways to do it but i don't want to spend another few months on figuring it out.
IntPtr hardwareConverted = new IntPtr(hardwareID);
//this marshals the void* into an IntPtr that you can play around with as normal, in managed memory.

【讨论】：