使用dart:ffi实现winapi(SendInput)

import 'dart:ffi';
import 'dart:io';

void main() {
  final kernel32 = DynamicLibrary.open('kernel32.dll');

  final sendInputPtr = kernel32.lookupFunction<
      Int32 Function(Int32, Pointer<Input>, Int32),
      int Function(int, Pointer<Input>, int)>('SendInput');

  final input = allocate<Input>();
  input.ref.type = INPUT_KEYBOARD;
  input.ref.ki.wVk = 0x41; // 'A' key
  input.ref.ki.dwFlags = KEYEVENTF_KEYDOWN;

  sendInputPtr(1, input, sizeOf<Input>());

  input.ref.ki.dwFlags = KEYEVENTF_KEYUP;
  sendInputPtr(1, input, sizeOf<Input>());

  free(input);
}

class Input extends Struct {
  @Int32('type')
  external int type;

  @Int32('ki.wVk')
  external int wVk;

  @Int32('ki.dwFlags')
  external int dwFlags;
}

const int INPUT_KEYBOARD = 1;
const int KEYEVENTF_KEYDOWN = 0x0000;
const int KEYEVENTF_KEYUP = 0x0002;