1        /// <summary>
2        /// Takes a screenshot of a specified window and keeps the result in the clipboard.
3        /// </summary>
4        /// <param name="hwnd">Window handle</param>
5        private System.Drawing.Image GetScreenshot(int hwnd)
6        {
7            SetWindowPos((IntPtr)hwnd, HWND_TOPMOST, 0, 0, 0, 0, TOPMOST_FLAGS);
8
9            //?? it works but why?
10            Thread.Sleep(100);
11
12            SetForegroundWindow((IntPtr)hwnd);
13
14            uint intReturn = 0;
15            INPUT structInput;
16            structInput = new INPUT();
17            structInput.type = (uint)1;
18            structInput.ki.wScan = 0;
19            structInput.ki.time = 0;
20            structInput.ki.dwFlags = 0;
21            structInput.ki.dwExtraInfo = 0;
22
23            //Key down Alt Key
24            structInput.ki.wVk = (ushort)VK.MENU;
25            intReturn = SendInput((uint)1, ref structInput, Marshal.SizeOf(structInput));
26
27            //Key down Print Screen
28            structInput.ki.wVk = (ushort)VK.SNAPSHOT;//vk;
29            intReturn = SendInput((uint)1, ref structInput, Marshal.SizeOf(structInput));
30
31            //Key up Print Screen
32            structInput.ki.dwFlags = KEYEVENTF_KEYUP;
33            structInput.ki.wVk = (ushort)VK.SNAPSHOT;//vk;
34            intReturn = SendInput((uint)1, ref structInput, Marshal.SizeOf(structInput));
35
36            //Key up Alt
37            structInput.ki.dwFlags = KEYEVENTF_KEYUP;
38            structInput.ki.wVk = (ushort)VK.MENU;
39            intReturn = SendInput((uint)1, ref structInput, Marshal.SizeOf(structInput));
40
41            //Need to let the print screen copy catch up with the rest of the code, other wise the clipboard will be read before
42            //it is written to
43            Thread.Sleep(100);
44
45            Win32.SetWindowPos((IntPtr)hwnd, HWND_NOTOPMOST, 0, 0, 0, 0, Win32.TOPMOST_FLAGS);
46
47            System.Windows.Forms.IDataObject data = Clipboard.GetDataObject();
48
49            try
50            {
51                if (data.GetDataPresent(DataFormats.Bitmap))
52                {
53                    System.Drawing.Image image = (System.Drawing.Image)data.GetData(DataFormats.Bitmap, true);
54                    return image;
55                }
56                else throw new Exception("Expected bitmap image.");
57            }
58            catch (Exception ex)
59            {
60                return null;
61            }
62        }
63
64        // For Windows Mobile, replace user32.dll with coredll.dll
65        [DllImport("user32.dll")]
66        [return: MarshalAs(UnmanagedType.Bool)]
67        public static extern bool SetForegroundWindow(IntPtr hWnd);
68
69        [DllImport("user32.dll")]
70        public static extern bool SetWindowPos(IntPtr hWnd, IntPtr hWndInsertAfter, int X,
71           int Y, int cx, int cy, uint uFlags);
72
73        public const ushort KEYEVENTF_KEYUP = 0x0002;
74
75        public enum VK : ushort
76        {
77            SHIFT = 0x10,
78            CONTROL = 0x11,
79            MENU = 0x12,
80            ESCAPE = 0x1B,
81            BACK = 0x08,
82            TAB = 0x09,
83            RETURN = 0x0D,
84            PRIOR = 0x21,
85            NEXT = 0x22,
86            END = 0x23,
87            HOME = 0x24,
88            LEFT = 0x25,
89            UP = 0x26,
90            RIGHT = 0x27,
91            DOWN = 0x28,
92            SELECT = 0x29,
93            PRINT = 0x2A,
94            EXECUTE = 0x2B,
95            SNAPSHOT = 0x2C,
96            INSERT = 0x2D,
97            DELETE = 0x2E,
98            HELP = 0x2F,
99            NUMPAD0 = 0x60,
100            NUMPAD1 = 0x61,
101            NUMPAD2 = 0x62,
102            NUMPAD3 = 0x63,
103            NUMPAD4 = 0x64,
104            NUMPAD5 = 0x65,
105            NUMPAD6 = 0x66,
106            NUMPAD7 = 0x67,
107            NUMPAD8 = 0x68,
108            NUMPAD9 = 0x69,
109            MULTIPLY = 0x6A,
110            ADD = 0x6B,
111            SEPARATOR = 0x6C,
112            SUBTRACT = 0x6D,
113            DECIMAL = 0x6E,
114            DIVIDE = 0x6F,
115            F1 = 0x70,
116            F2 = 0x71,
117            F3 = 0x72,
118            F4 = 0x73,
119            F5 = 0x74,
120            F6 = 0x75,
121            F7 = 0x76,
122            F8 = 0x77,
123            F9 = 0x78,
124            F10 = 0x79,
125            F11 = 0x7A,
126            F12 = 0x7B,
127            OEM_1 = 0xBA,   // ',:' for US
128            OEM_PLUS = 0xBB,   // '+' any country
129            OEM_COMMA = 0xBC,   // ',' any country
130            OEM_MINUS = 0xBD,   // '-' any country
131            OEM_PERIOD = 0xBE,   // '.' any country
132            OEM_2 = 0xBF,   // '/?' for US
133            OEM_3 = 0xC0,   // '`~' for US
134            MEDIA_NEXT_TRACK = 0xB0,
135            MEDIA_PREV_TRACK = 0xB1,
136            MEDIA_STOP = 0xB2,
137            MEDIA_PLAY_PAUSE = 0xB3,
138            LWIN = 0x5B,
139            RWIN = 0x5C
140        }
141
142        public struct KEYBDINPUT
143        {
144            public ushort wVk;
145            public ushort wScan;
146            public uint dwFlags;
147            public long time;
148            public uint dwExtraInfo;
149        };
150
151        [StructLayout(LayoutKind.Explicit, Size = 28)]
152        public struct INPUT
153        {
154            [FieldOffset(0)]
155            public uint type;
156            [FieldOffset(4)]
157            public KEYBDINPUT ki;
158        };
159
160        public static readonly IntPtr HWND_TOPMOST = new IntPtr(-1);
161        public static readonly IntPtr HWND_NOTOPMOST = new IntPtr(-2);
162        public static readonly IntPtr HWND_TOP = new IntPtr(0);
163        public static readonly IntPtr HWND_BOTTOM = new IntPtr(1);
164
165        // From winuser.h
166        public const UInt32 SWP_NOSIZE = 0x0001;
167        public const UInt32 SWP_NOMOVE = 0x0002;
168        public const UInt32 SWP_NOZORDER = 0x0004;
169        public const UInt32 SWP_NOREDRAW = 0x0008;
170        public const UInt32 SWP_NOACTIVATE = 0x0010;
171        public const UInt32 SWP_FRAMECHANGED = 0x0020;  /* The frame changed: send WM_NCCALCSIZE */
172        public const UInt32 SWP_SHOWWINDOW = 0x0040;
173        public const UInt32 SWP_HIDEWINDOW = 0x0080;
174        public const UInt32 SWP_NOCOPYBITS = 0x0100;
175        public const UInt32 SWP_NOOWNERZORDER = 0x0200;  /* Don't do owner Z ordering */
176        public const UInt32 SWP_NOSENDCHANGING = 0x0400;  /* Don't send WM_WINDOWPOSCHANGING */
177
178        public const UInt32 TOPMOST_FLAGS = SWP_NOMOVE | SWP_NOSIZE;