Overview\u00a0<\/p>\n
Declare a method in c# to access unmanaged function<\/p>\n
\n[DllImport(\"kernel32.dll\", EntryPoint=\"GetPrivateProfileString\")]
\nprivate static extern int GetPrivateProfileString(string lpAppName,
\nstring lpKeyName, string lpDefault, StringBuilder lpReturnedString,
\nint nSize, string lpFileName);
\n<\/code><\/ul>\n
\n[DllImport(\"kernel32.dll\", EntryPoint=\"WritePrivateProfileString\")]
\nprivate static extern bool WritePrivateProfileString(string lpAppName,
\nstring lpKeyName, string lpString, string lpFileName);<\/code><\/ul>\n<\/li>\n<\/ul>\nCall unmanaged\u00a0function that uses callbacks<\/p>\n
\n- Declare a delegate with the required signature for the callback<\/li>\n
- Define call back function to be passed<\/li>\n
- Pass the callback to the function<\/li>\n
- Example
\n
\n\/\/ The signature for the callback method.
\npublic delegate void OnXMConnect();
\npublic delegate void OnXMDisconnect();
\n\/\/ The call back methods
\nprivate static void OnXMConn(){
\nConsole.WriteLine(\"Connected\");
\n}
\nprivate static void OnXMDisconn(){
\nConsole.WriteLine(\"DisConnected\");
\n}\/\/ Pass the callbacks to unmanaged function
\nprivate static void TestXM(){
\nUSB_RegisterCallbacks(OnXMConn, OnXMDisconn);
\n}<\/code><\/li>\n<\/ul>\nPass Struct as parameter<\/p>\n
\n- Define a class to represent C struct<\/li>\n
- Annotate with [StructLayout(LayoutKind.Sequential)]<\/li>\n
- Declare struct members as class member variables<\/li>\n
- Annotate variables with [MarshalAs…] if needed<\/li>\n
- Example
\n
\n\/\/ Define struct as a class
\n[StructLayout(LayoutKind.Sequential)]
\npublic class OSVersionInfo
\n{
\npublic int dwOSVersionInfoSize;
\npublic int dwMajorVersion;
\npublic int dwMinorVersion;
\npublic int dwBuildNumber;
\npublic int dwPlatformId;
\n[MarshalAs(UnmanagedType.ByValTStr, SizeConst=128)]
\npublic string szCSDVersion;
\n}\/\/ Use the class
\n[DllImport(\"kernel32.dll\")]
\npublic static extern bool GetVersionEx([In, Out] OSVersionInfo osvi);private static void TestStruct()
\n{
\nOSVersionInfo osvi = new OSVersionInfo();
\nosvi.dwOSVersionInfoSize = Marshal.SizeOf(osvi);GetVersionEx(osvi);<\/p>\nConsole.WriteLine(\"Major version: {0}\", osvi.dwMajorVersion);
\nConsole.WriteLine(\"Minor version: {0}\", osvi.dwMinorVersion);
\n}<\/p>\n
<\/code><\/li>\n<\/ul>\n
\/\/ if RECT is a class, not struct
\n
\n[DllImport(\"user32.dll\")]
\npublic static extern int GetWindowRect(int hwnd, [MarshalAs(UnmanagedType.LPStruct)] RECT rc);
\n<\/code><\/p>\n","protected":false},"excerpt":{"rendered":"Overview\u00a0 PInvoke is used to invoke\u00a0unmanaged dlls kernel32.dll process loading context switching file, memory i\/o user32.dll windows, menus, dialog boxes, icons, etc. GDI32 drawing capabilities Declare a method in c# to access unmanaged function Declare this method as both static … Continue reading