MSJO.kr닷넷 7.0 이전 버전에서는 대부분 외부 DLL 파일을 Import 하거나 P/Invoke1를 활용하여 Native DLL(Unmanaged DLL)에 있는 함수를 호출하기 위해 DllImport를 사용해 왔다. 8.0버전부터는 LibraryImport의 사용을 권장한다.
LibraryImport가 새로 생겨난 이유는 DllImport가 마샬링을 런타임에서 수행해서 IL 코드를 emit 한다고 하는데 NativeAOT 등 동적으로 IL 코드를 생성할 수 없는 환경에서 쓸 수 없으므로 LibraryImport의 소스 생성기 기능을 이용해 컴파일 시점에서 마샬링 코드를 삽입한다.2
기존에 작성했던 DllImport에서 LibraryImport 스타일로 변경할 때 몇 가지 변경 사항이 있는데 이 부분을 간단한 예제를 통하여 정리하였다. ~.csproj를 열어 <PropertyGroup>사이에<AllowUnsafeBlocks>true</AllowUnsafeBlocks>를 추가한다.
WPF에서 윈도우 이동(DragMove)
[LibraryImport("user32.DLL", EntryPoint = "ReleaseCapture", StringMarshalling = StringMarshalling.Utf16)]
[UnmanagedCallConv(CallConvs = [typeof(CallConvStdcall)])]
[return: MarshalAs(UnmanagedType.Bool)]
private static partial bool ReleaseCapture();
[LibraryImport("user32.DLL", EntryPoint = "SendMessageW", StringMarshalling = StringMarshalling.Utf16)]
[UnmanagedCallConv(CallConvs = [typeof(CallConvStdcall)])]
[return: MarshalAs(UnmanagedType.SysInt)]
private static partial IntPtr SendMessageW(IntPtr hWnd, uint wMsg, IntPtr wParam, IntPtr lParam);
[LibraryImport("USER32.DLL", EntryPoint = "FindWindowW", StringMarshalling = StringMarshalling.Utf16)]
[UnmanagedCallConv(CallConvs = [typeof(CallConvStdcall)])]
[return: MarshalAs(UnmanagedType.SysInt)]
private static partial IntPtr FindWindowW(string? lpClassName, string? lpWindowName);
public static void DragMoveWindow(string windowTitle)
{
// MainWindow? mainWindow = Application.Current.MainWindow as MainWindow;
// _ = ReleaseCapture();
// _ = SendMessageW(mainWindow == null ? Process.GetCurrentProcess().MainWindowHandle : FindWindowW(null, mainWindow.Title),
// 0x112, 0xf012, 0);
_ = ReleaseCapture();
_ = SendMessageW(FindWindowW(null, windowTitle), 0x112, 0xf012, 0);
}
INI Read/Write 예제
[LibraryImport("kernel32.dll", EntryPoint = "GetPrivateProfileStringW", StringMarshalling = StringMarshalling.Utf16)]
[UnmanagedCallConv(CallConvs = [typeof(CallConvStdcall)])]
private static partial void GetPrivateProfileStringW(string lpAppName, string lpKeyName, string lpDefault, [Out] char[] lpReturnedString, int nSize, string lpFileName);
[LibraryImport("kernel32.dll", EntryPoint = "WritePrivateProfileStringW", StringMarshalling = StringMarshalling.Utf16)]
[UnmanagedCallConv(CallConvs = [typeof(CallConvStdcall)])]
[return: MarshalAs(UnmanagedType.Bool)]
private static partial bool WritePrivateProfileStringW(string lpAppName, string lpKeyName, string lpString, string lpFileName);
private const string INI_FILE = "file_path";
public static string Read(string key)
{
try
{
char[] _output = new char[1024];
GetPrivateProfileStringW(SECTION, key, "", _output, output.length, INI_FILE);
output = output.Where(c => c != '\0').ToArray();
return new string(_output);
}
catch (Exception _ex)
{
LogHelper.Logger.Debug($"IniHelper Read ERROR : {_ex.Message}");
return string.Empty;
}
}
public static void Write(string key, string value)
{
try
{
_ = WritePrivateProfileStringW(SECTION, key, value, INI_FILE);
}
catch (Exception _ex)
{
LogHelper.Logger.Debug($"IniHelper Write ERROR : {_ex.Message}");
}
}
SendMessage IPC
private const uint WM_SETTEXT = 0x000C;
[LibraryImport("user32.DLL", EntryPoint = "SendMessageW", StringMarshalling = StringMarshalling.Utf16)]
[UnmanagedCallConv(CallConvs = [typeof(CallConvStdcall)])]
[return: MarshalAs(UnmanagedType.SysInt)]
private static partial IntPtr SendMessageW(IntPtr hWnd, uint wMsg, IntPtr wParam, IntPtr lParam);
[LibraryImport("USER32.DLL", EntryPoint = "FindWindowW", StringMarshalling = StringMarshalling.Utf16)]
[UnmanagedCallConv(CallConvs = [typeof(CallConvStdcall)])]
[return: MarshalAs(UnmanagedType.SysInt)]
private static partial IntPtr FindWindowW(string? lpClassName, string? lpWindowName);
public static async Task SendMessage(string message)
{
await Task.Run(() =>
{
try
{
IntPtr handle = FindWindowW(null, "TITLE_XXX");
_ = SendMessageW(handle, WM_SETTEXT, IntPtr.Zero, Marshal.StringToHGlobalAuto(message));
}
catch (Exception ex)
{
LogHelper.Logger.Error($"SendMessage ERROR : {ex.Message}");
}
});
}
// 받는 부분
private static IntPtr WndProc(IntPtr hWnd, int msg, IntPtr wParam, IntPtr lParam, ref bool handled)
{
try
{
switch (msg)
{
case 0x0011: // WM_QUERYENDSESSION
_mainWindow.Close();
handled = true;
break;
case 0x000C: // WM_SETTEXT
ReceiveMessage(Marshal.PtrToStringAuto(lParam) ?? string.Empty);
handled = true;
break;
// case 0x0400: // WM_USER
// ReceiveMessageUser(Marshal.PtrToStringAuto(lParam) ?? "");
// handled = true;
// break;
// case 0x004A: // WM_COPYDATA
// ReceiveMessageCopyData(Marshal.PtrToStructure<CopyDataStruct>(lParam).LpData);
// handled = true;
// break;
}
return IntPtr.Zero; // 변경
}
catch (Exception ex)
{
LogHelper.Logger.Error($"WndProc Error : {ex.Message}");
return IntPtr.Zero;
}
}
AOT 활용
// AOT(Native) : TestAot.dll
[UnmanagedCallersOnly(EntryPoint = "GetTest")]
public static IntPtr GetTest(IntPtr inputString)
{
string? tmpString = Marshal.PtrToStringAuto(inputString);
return Marshal.StringToHGlobalAuto("문자열 : " + tmpString);
}
// Managed code
[LibraryImport("TestAot.dll", EntryPoint = "GetTest", SetLastError = true, StringMarshalling = StringMarshalling.Utf16)]
[UnmanagedCallConv(CallConvs = [typeof(CallConvStdcall)])]
[return: MarshalAs(UnmanagedType.SysInt)]
private static partial IntPtr GetTest([MarshalAs(UnmanagedType.LPWStr)] string inputStr);
private string? GetTestEx(string inputString)
{
try
{
return Marshal.PtrToStringAuto(GetTest(inputString));
}
catch (Exception ex)
{
LogHelper.Logger.Error($"GetTestEx ERROR : {ex.Message}");
return (false, ex.Message);
}
}