问题描述
我正在开发一个自动化接口程序，我希望通过使用针对 C++ 的 COPYDATA API 的机器软件来增强功能。目标是通过我自己的软件控制和报告机器的状态。
该方法使用了迄今为止我没有任何经验的指针和内存分配。
我查看了许多其他来源，例如 this，但目前没有运气。我尝试了以下代码来尝试在机器软件上运行程序。
class Program
{
[DllImport("User32.dll",SetLastError = true,EntryPoint = "FindWindow")]
public static extern IntPtr FindWindow(String lpClassName,String lpWindowName);
[DllImport("User32.dll",EntryPoint = "SendMessage")]
public static extern IntPtr SendMessage(IntPtr hWnd,int Msg,int wParam,ref copYDATASTRUCT lParam);
[StructLayout(LayoutKind.Sequential)]
public struct copYDATASTRUCT
{
public IntPtr dwData; // Any value the sender chooses. Perhaps its main window handle?
public int cbData; // The count of bytes in the message.
public IntPtr lpData; // The address of the message.
}
const int WM_copYDATA = 0x004A;
const int EXTERNAL_CD_COMMAND_RUN_ASYNC = 0x8001;
static void Main(string[] args)
{
Console.WriteLine("{0} bit process.",(IntPtr.Size == 4) ? "32" : "64");
Console.Write("Press ENTER to run test.");
Console.ReadLine();
IntPtr hwnd = FindWindow(null,"InSpecAppFrame");
Console.WriteLine("hwnd = {0:X}",hwnd.ToInt64());
var cds = new copYDATASTRUCT();
byte[] buff = Encoding.ASCII.GetBytes("C:\\Users\\Desktop\\copYDATATEST.iwp");
cds.dwData = (IntPtr)EXTERNAL_CD_COMMAND_RUN_ASYNC;
cds.lpData = Marshal.AllocHGlobal(buff.Length);
Marshal.copy(buff,cds.lpData,buff.Length);
cds.cbData = buff.Length;
var ret = SendMessage(hwnd,WM_copYDATA,ref cds);
Console.WriteLine("Return value is {0}",ret);
Marshal.FreeHGlobal(cds.lpData);
Console.ReadLine();
}
}
运行此代码会为 hwnd 和 ret 返回 0，并且机器软件没有反应。
发送命令是第一步，下一步是尝试获得响应，以便我可以监控机器状态等。
解决方法
作为 Alejandro 所写内容的旁注（我认为这是正确的），您可以稍微简化代码，删除数据的副本。您可以直接“固定”您的 byte[]。请务必记住“取消固定”它（因此，try/finally 块）
您的代码中存在另一个潜在问题（我仅在第二遍代码时看到的问题）：C 字符串必须以 \0 终止（因此 "Foo" 必须为 {{1} })。您的 "Foo\0" 不保证 Encoding.ASCII 终止。这样做的经典方法是使 \0 比需要的“大一点”。我已经完成了必要的更改。
byte[]请注意，您甚至可以使用 [DllImport("User32.dll",SetLastError = true)]
public static extern IntPtr SendMessage(IntPtr hWnd,int Msg,int wParam,ref COPYDATASTRUCT lParam);
[DllImport("user32.dll",SetLastError = true)]
static extern IntPtr FindWindow(string lpClassName,string lpWindowName);
[StructLayout(LayoutKind.Sequential)]
public struct COPYDATASTRUCT
{
public IntPtr dwData; // Any value the sender chooses. Perhaps its main window handle?
public int cbData; // The count of bytes in the message.
public IntPtr lpData; // The address of the message.
}
[StructLayout(LayoutKind.Sequential)]
public struct ExternalGetPositionType
{
public double X;
public double Y;
public double Z;
public double W;
}
const int WM_COPYDATA = 0x004A;
const int EXTERNAL_CD_COMMAND_RUN_ASYNC = 0x8001;
const int EXTERNAL_CD_GET_POSITION_PCS = 0x8011;
const int EXTERNAL_CD_GET_POSITION_MCS = 0x8012;
static void Main(string[] args)
{
Console.WriteLine("{0} bit process.",(IntPtr.Size == 4) ? "32" : "64");
Console.Write("Press ENTER to run test.");
Console.ReadLine();
IntPtr hwnd = FindWindow(null,"Form1");
Console.WriteLine("hwnd = {0:X}",hwnd.ToInt64());
if (hwnd == IntPtr.Zero)
{
throw new Exception("hwnd not found");
}
IntPtr ret = RunAsync(hwnd,@"C:\Users\Desktop\COPYDATATEST.iwp");
Console.WriteLine($"Return value for EXTERNAL_CD_COMMAND_RUN_ASYNC is {ret}");
ret = GetPosition(hwnd,true,new ExternalGetPositionType { X = 1,Y = 2,Z = 3,W = 4 });
Console.WriteLine($"Return value for EXTERNAL_CD_GET_POSITION_PCS is {ret}");
ret = GetPosition(hwnd,false,new ExternalGetPositionType { X = 10,Y = 20,Z = 30,W = 40 });
Console.WriteLine($"Return value for EXTERNAL_CD_GET_POSITION_MCS is {ret}");
Console.ReadLine();
}
public static IntPtr RunAsync(IntPtr hwnd,string str)
{
// We have to add a \0 terminator,so len + 1 / len + 2 for Unicode
int len = Encoding.Default.GetByteCount(str);
var buff = new byte[len + 1]; // len + 2 for Unicode
Encoding.Default.GetBytes(str,str.Length,buff,0);
IntPtr ret;
GCHandle h = default(GCHandle);
try
{
h = GCHandle.Alloc(buff,GCHandleType.Pinned);
var cds = new COPYDATASTRUCT();
cds.dwData = (IntPtr)EXTERNAL_CD_COMMAND_RUN_ASYNC;
cds.lpData = h.AddrOfPinnedObject();
cds.cbData = buff.Length;
ret = SendMessage(hwnd,WM_COPYDATA,ref cds);
}
finally
{
if (h.IsAllocated)
{
h.Free();
}
}
return ret;
}
public static IntPtr GetPosition(IntPtr hwnd,bool pcs,ExternalGetPositionType position)
{
// We cheat here... It is much easier to pin an array than to copy around a struct
var positions = new[]
{
position
};
IntPtr ret;
GCHandle h = default(GCHandle);
try
{
h = GCHandle.Alloc(positions,GCHandleType.Pinned);
var cds = new COPYDATASTRUCT();
cds.dwData = pcs ? (IntPtr)EXTERNAL_CD_GET_POSITION_PCS : (IntPtr)EXTERNAL_CD_GET_POSITION_MCS;
cds.lpData = h.AddrOfPinnedObject();
cds.cbData = Marshal.SizeOf<ExternalGetPositionType>();
ret = SendMessage(hwnd,ref cds);
}
finally
{
if (h.IsAllocated)
{
h.Free();
}
}
return ret;
}
编码代替 ASCII，这样会更好一些。
如果您想接收消息，请在您的 Winforms 中执行：
Default请注意，如果您同时控制发送方和接收方，最好将 Unicode 用于字符串参数。您必须同时修改发送方和接收方：protected override void WndProc(ref Message m)
{
if (m.Msg == WM_COPYDATA)
{
COPYDATASTRUCT cds = Marshal.PtrToStructure<COPYDATASTRUCT>(m.LParam);
if (cds.dwData == (IntPtr)EXTERNAL_CD_COMMAND_RUN_ASYNC)
{
string str = Marshal.PtrToStringAnsi(cds.lpData);
Debug.WriteLine($"EXTERNAL_CD_COMMAND_RUN_ASYNC: {str}");
m.Result = (IntPtr)100; // If you want to return a value
}
else if (cds.dwData == (IntPtr)EXTERNAL_CD_GET_POSITION_PCS)
{
if (cds.cbData >= Marshal.SizeOf<ExternalGetPositionType>())
{
var position = Marshal.PtrToStructure<ExternalGetPositionType>(cds.lpData);
Debug.WriteLine($"EXTERNAL_CD_GET_POSITION_PCS: X = {position.X},Y = {position.Y},Z = {position.Z},W = {position.W}");
m.Result = (IntPtr)200;
}
else
{
m.Result = (IntPtr)0;
}
}
else if (cds.dwData == (IntPtr)EXTERNAL_CD_GET_POSITION_MCS)
{
if (cds.cbData >= Marshal.SizeOf<ExternalGetPositionType>())
{
var position = Marshal.PtrToStructure<ExternalGetPositionType>(cds.lpData);
Debug.WriteLine($"EXTERNAL_CD_GET_POSITION_MCS: X = {position.X},W = {position.W}");
m.Result = (IntPtr)300;
}
else
{
m.Result = (IntPtr)0;
}
}
return;
}
base.WndProc(ref m);
}
/Encoding.Unicode.GetByteCount，+2 而不是 +1 和 Encoding.Unicode.GetBytes。