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Created December 21, 2023 15:13
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Simulate keyboard and mouse input in WPF (similar to sendkeys in winform)
using System;
using System.ComponentModel;
using System.Drawing;
using System.Linq;
using System.Runtime.InteropServices;
using System.Security;
using System.Security.Permissions;
using System.Windows.Input;
namespace Demo
{
/// <summary>
/// Native methods
/// </summary>
internal static class NativeMethods
{
//User32 wrappers cover API's used for Mouse input
#region User32
// Two special bitmasks we define to be able to grab
// shift and character information out of a VKey.
internal const int VKeyShiftMask = 0x0100;
internal const int VKeyCharMask = 0x00FF;
// Various Win32 constants
internal const int KeyeventfExtendedkey = 0x0001;
internal const int KeyeventfKeyup = 0x0002;
internal const int KeyeventfScancode = 0x0008;
internal const int MouseeventfVirtualdesk = 0x4000;
internal const int SMXvirtualscreen = 76;
internal const int SMYvirtualscreen = 77;
internal const int SMCxvirtualscreen = 78;
internal const int SMCyvirtualscreen = 79;
internal const int XButton1 = 0x0001;
internal const int XButton2 = 0x0002;
internal const int WheelDelta = 120;
internal const int InputMouse = 0;
internal const int InputKeyboard = 1;
// Various Win32 data structures
[StructLayout(LayoutKind.Sequential)]
internal struct INPUT
{
internal int type;
internal INPUTUNION union;
};
[StructLayout(LayoutKind.Explicit)]
internal struct INPUTUNION
{
[FieldOffset(0)]
internal MOUSEINPUT mouseInput;
[FieldOffset(0)]
internal KEYBDINPUT keyboardInput;
};
[StructLayout(LayoutKind.Sequential)]
internal struct MOUSEINPUT
{
internal int dx;
internal int dy;
internal int mouseData;
internal int dwFlags;
internal int time;
internal IntPtr dwExtraInfo;
};
[StructLayout(LayoutKind.Sequential)]
internal struct KEYBDINPUT
{
internal short wVk;
internal short wScan;
internal int dwFlags;
internal int time;
internal IntPtr dwExtraInfo;
};
[Flags]
internal enum SendMouseInputFlags
{
Move = 0x0001,
LeftDown = 0x0002,
LeftUp = 0x0004,
RightDown = 0x0008,
RightUp = 0x0010,
MiddleDown = 0x0020,
MiddleUp = 0x0040,
XDown = 0x0080,
XUp = 0x0100,
Wheel = 0x0800,
Absolute = 0x8000,
};
// Importing various Win32 APIs that we need for input
[DllImport("user32.dll", ExactSpelling = true, CharSet = CharSet.Auto)]
internal static extern int GetSystemMetrics(int nIndex);
[DllImport("user32.dll", CharSet = CharSet.Auto)]
internal static extern int MapVirtualKey(int nVirtKey, int nMapType);
[DllImport("user32.dll", SetLastError = true)]
internal static extern int SendInput(int nInputs, ref INPUT mi, int cbSize);
[DllImport("user32.dll", CharSet = CharSet.Auto)]
internal static extern short VkKeyScan(char ch);
#endregion
}
/// <summary>
/// Exposes a simple interface to common mouse operations, allowing the user to simulate mouse input.
/// </summary>
/// <example>The following code moves to screen coordinate 100,100 and left clicks.
/// <code>
/**
Mouse.MoveTo(new Point(100, 100));
Mouse.Click(MouseButton.Left);
*/
/// </code>
/// </example>
public static class Mouse
{
/// <summary>
/// Clicks a mouse button.
/// </summary>
/// <param name="mouseButton">The mouse button to click.</param>
public static void Click(MouseButton mouseButton)
{
Down(mouseButton);
Up(mouseButton);
}
/// <summary>
/// Double-clicks a mouse button.
/// </summary>
/// <param name="mouseButton">The mouse button to click.</param>
public static void DoubleClick(MouseButton mouseButton)
{
Click(mouseButton);
Click(mouseButton);
}
/// <summary>
/// Performs a mouse-down operation for a specified mouse button.
/// </summary>
/// <param name="mouseButton">The mouse button to use.</param>
public static void Down(MouseButton mouseButton)
{
switch (mouseButton)
{
case MouseButton.Left:
SendMouseInput(0, 0, 0, NativeMethods.SendMouseInputFlags.LeftDown);
break;
case MouseButton.Right:
SendMouseInput(0, 0, 0, NativeMethods.SendMouseInputFlags.RightDown);
break;
case MouseButton.Middle:
SendMouseInput(0, 0, 0, NativeMethods.SendMouseInputFlags.MiddleDown);
break;
case MouseButton.XButton1:
SendMouseInput(0, 0, NativeMethods.XButton1, NativeMethods.SendMouseInputFlags.XDown);
break;
case MouseButton.XButton2:
SendMouseInput(0, 0, NativeMethods.XButton2, NativeMethods.SendMouseInputFlags.XDown);
break;
default:
throw new InvalidOperationException("Unsupported MouseButton input.");
}
}
/// <summary>
/// Moves the mouse pointer to the specified screen coordinates.
/// </summary>
/// <param name="point">The screen coordinates to move to.</param>
public static void MoveTo(Point point)
{
SendMouseInput(point.X, point.Y, 0, NativeMethods.SendMouseInputFlags.Move | NativeMethods.SendMouseInputFlags.Absolute);
}
/// <summary>
/// Resets the system mouse to a clean state.
/// </summary>
public static void Reset()
{
MoveTo(new Point(0, 0));
if (System.Windows.Input.Mouse.LeftButton == MouseButtonState.Pressed)
{
SendMouseInput(0, 0, 0, NativeMethods.SendMouseInputFlags.LeftUp);
}
if (System.Windows.Input.Mouse.MiddleButton == MouseButtonState.Pressed)
{
SendMouseInput(0, 0, 0, NativeMethods.SendMouseInputFlags.MiddleUp);
}
if (System.Windows.Input.Mouse.RightButton == MouseButtonState.Pressed)
{
SendMouseInput(0, 0, 0, NativeMethods.SendMouseInputFlags.RightUp);
}
if (System.Windows.Input.Mouse.XButton1 == MouseButtonState.Pressed)
{
SendMouseInput(0, 0, NativeMethods.XButton1, NativeMethods.SendMouseInputFlags.XUp);
}
if (System.Windows.Input.Mouse.XButton2 == MouseButtonState.Pressed)
{
SendMouseInput(0, 0, NativeMethods.XButton2, NativeMethods.SendMouseInputFlags.XUp);
}
}
/// <summary>
/// Simulates scrolling of the mouse wheel up or down.
/// </summary>
/// <param name="lines">The number of lines to scroll. Use positive numbers to scroll up and negative numbers to scroll down.</param>
public static void Scroll(double lines)
{
int amount = (int)(NativeMethods.WheelDelta * lines);
SendMouseInput(0, 0, amount, NativeMethods.SendMouseInputFlags.Wheel);
}
/// <summary>
/// Performs a mouse-up operation for a specified mouse button.
/// </summary>
/// <param name="mouseButton">The mouse button to use.</param>
public static void Up(MouseButton mouseButton)
{
switch (mouseButton)
{
case MouseButton.Left:
SendMouseInput(0, 0, 0, NativeMethods.SendMouseInputFlags.LeftUp);
break;
case MouseButton.Right:
SendMouseInput(0, 0, 0, NativeMethods.SendMouseInputFlags.RightUp);
break;
case MouseButton.Middle:
SendMouseInput(0, 0, 0, NativeMethods.SendMouseInputFlags.MiddleUp);
break;
case MouseButton.XButton1:
SendMouseInput(0, 0, NativeMethods.XButton1, NativeMethods.SendMouseInputFlags.XUp);
break;
case MouseButton.XButton2:
SendMouseInput(0, 0, NativeMethods.XButton2, NativeMethods.SendMouseInputFlags.XUp);
break;
default:
throw new InvalidOperationException("Unsupported MouseButton input.");
}
}
/// <summary>
/// Sends mouse input.
/// </summary>
/// <param name="x">x coordinate</param>
/// <param name="y">y coordinate</param>
/// <param name="data">scroll wheel amount</param>
/// <param name="flags">SendMouseInputFlags flags</param>
[PermissionSet(SecurityAction.Assert, Name = "FullTrust")]
private static void SendMouseInput(int x, int y, int data, NativeMethods.SendMouseInputFlags flags)
{
PermissionSet permissions = new PermissionSet(PermissionState.Unrestricted);
permissions.Demand();
int intflags = (int)flags;
if ((intflags & (int)NativeMethods.SendMouseInputFlags.Absolute) != 0)
{
// Absolute position requires normalized coordinates.
NormalizeCoordinates(ref x, ref y);
intflags |= NativeMethods.MouseeventfVirtualdesk;
}
NativeMethods.INPUT mi = new NativeMethods.INPUT();
mi.type = NativeMethods.InputMouse;
mi.union.mouseInput.dx = x;
mi.union.mouseInput.dy = y;
mi.union.mouseInput.mouseData = data;
mi.union.mouseInput.dwFlags = intflags;
mi.union.mouseInput.time = 0;
mi.union.mouseInput.dwExtraInfo = new IntPtr(0);
if (NativeMethods.SendInput(1, ref mi, Marshal.SizeOf(mi)) == 0)
{
throw new Win32Exception(Marshal.GetLastWin32Error());
}
}
private static void NormalizeCoordinates(ref int x, ref int y)
{
int vScreenWidth = NativeMethods.GetSystemMetrics(NativeMethods.SMCxvirtualscreen);
int vScreenHeight = NativeMethods.GetSystemMetrics(NativeMethods.SMCyvirtualscreen);
int vScreenLeft = NativeMethods.GetSystemMetrics(NativeMethods.SMXvirtualscreen);
int vScreenTop = NativeMethods.GetSystemMetrics(NativeMethods.SMYvirtualscreen);
// Absolute input requires that input is in 'normalized' coords - with the entire
// desktop being (0,0)...(65536,65536). Need to convert input x,y coords to this
// first.
//
// In this normalized world, any pixel on the screen corresponds to a block of values
// of normalized coords - eg. on a 1024x768 screen,
// y pixel 0 corresponds to range 0 to 85.333,
// y pixel 1 corresponds to range 85.333 to 170.666,
// y pixel 2 correpsonds to range 170.666 to 256 - and so on.
// Doing basic scaling math - (x-top)*65536/Width - gets us the start of the range.
// However, because int math is used, this can end up being rounded into the wrong
// pixel. For example, if we wanted pixel 1, we'd get 85.333, but that comes out as
// 85 as an int, which falls into pixel 0's range - and that's where the pointer goes.
// To avoid this, we add on half-a-"screen pixel"'s worth of normalized coords - to
// push us into the middle of any given pixel's range - that's the 65536/(Width*2)
// part of the formula. So now pixel 1 maps to 85+42 = 127 - which is comfortably
// in the middle of that pixel's block.
// The key ting here is that unlike points in coordinate geometry, pixels take up
// space, so are often better treated like rectangles - and if you want to target
// a particular pixel, target its rectangle's midpoint, not its edge.
x = ((x - vScreenLeft) * 65536) / vScreenWidth + 65536 / (vScreenWidth * 2);
y = ((y - vScreenTop) * 65536) / vScreenHeight + 65536 / (vScreenHeight * 2);
}
}
/// <summary>
/// Exposes a simple interface to common keyboard operations, allowing the user to simulate keyboard input.
/// </summary>
/// <example>
/// The following code types "Hello world" with the specified casing,
/// and then types "hello, capitalized world" which will be in all caps because
/// the left shift key is being held down.
/// <code>
/**
Keyboard.Type("Hello world");
Keyboard.Press(Key.LeftShift);
Keyboard.Type("hello, capitalized world");
Keyboard.Release(Key.LeftShift);
*/
/// </code>
/// </example>
public static class Keyboard
{
#region Public Members
/// <summary>
/// Presses down a key.
/// </summary>
/// <param name="key">The key to press.</param>
public static void Press(Key key)
{
SendKeyboardInput(key, true);
}
/// <summary>
/// Releases a key.
/// </summary>
/// <param name="key">The key to release.</param>
public static void Release(Key key)
{
SendKeyboardInput(key, false);
}
/// <summary>
/// Resets the system keyboard to a clean state.
/// </summary>
public static void Reset()
{
foreach (Key key in Enum.GetValues(typeof(Key)))
{
if (key != Key.None && (System.Windows.Input.Keyboard.GetKeyStates(key) & KeyStates.Down) > 0)
{
Release(key);
}
}
}
/// <summary>
/// Performs a press-and-release operation for the specified key, which is effectively equivallent to typing.
/// </summary>
/// <param name="key">The key to press.</param>
public static void Type(Key key)
{
Press(key);
Release(key);
}
/// <summary>
/// Types the specified text.
/// </summary>
/// <param name="text">The text to type.</param>
public static void Type(string text)
{
foreach (char c in text)
{
// We get the vKey value for the character via a Win32 API. We then use bit masks to pull the
// upper and lower bytes to get the shift state and key information. We then use WPF KeyInterop
// to go from the vKey key info into a System.Windows.Input.Key data structure. This work is
// necessary because Key doesn't distinguish between upper and lower case, so we have to wrap
// the key type inside a shift press/release if necessary.
int vKeyValue = NativeMethods.VkKeyScan(c);
bool keyIsShifted = (vKeyValue & NativeMethods.VKeyShiftMask) == NativeMethods.VKeyShiftMask;
Key key = KeyInterop.KeyFromVirtualKey(vKeyValue & NativeMethods.VKeyCharMask);
if (keyIsShifted)
{
Type(key, new Key[] { Key.LeftShift });
}
else
{
Type(key);
}
}
}
#endregion
#region Private Members
/// <summary>
/// Types a key while a set of modifier keys are being pressed. Modifer keys
/// are pressed in the order specified and released in reverse order.
/// </summary>
/// <param name="key">Key to type.</param>
/// <param name="modifierKeys">Set of keys to hold down with key is typed.</param>
private static void Type(Key key, Key[] modifierKeys)
{
foreach (Key modiferKey in modifierKeys)
{
Press(modiferKey);
}
Type(key);
foreach (Key modifierKey in modifierKeys.Reverse())
{
Release(modifierKey);
}
}
/// <summary>
/// Injects keyboard input into the system.
/// </summary>
/// <param name="key">Indicates the key pressed or released. Can be one of the constants defined in the Key enum.</param>
/// <param name="press">True to inject a key press, false to inject a key release.</param>
[PermissionSet(SecurityAction.Assert, Name = "FullTrust")]
private static void SendKeyboardInput(Key key, bool press)
{
PermissionSet permissions = new PermissionSet(PermissionState.Unrestricted);
permissions.Demand();
NativeMethods.INPUT ki = new NativeMethods.INPUT();
ki.type = NativeMethods.InputKeyboard;
ki.union.keyboardInput.wVk = (short)KeyInterop.VirtualKeyFromKey(key);
ki.union.keyboardInput.wScan = (short)NativeMethods.MapVirtualKey(ki.union.keyboardInput.wVk, 0);
int dwFlags = 0;
if (ki.union.keyboardInput.wScan > 0)
{
dwFlags |= NativeMethods.KeyeventfScancode;
}
if (!press)
{
dwFlags |= NativeMethods.KeyeventfKeyup;
}
ki.union.keyboardInput.dwFlags = dwFlags;
if (ExtendedKeys.Contains(key))
{
ki.union.keyboardInput.dwFlags |= NativeMethods.KeyeventfExtendedkey;
}
ki.union.keyboardInput.time = 0;
ki.union.keyboardInput.dwExtraInfo = new IntPtr(0);
if (NativeMethods.SendInput(1, ref ki, Marshal.SizeOf(ki)) == 0)
{
throw new Win32Exception(Marshal.GetLastWin32Error());
}
}
// From the SDK:
// The extended-key flag indicates whether the keystroke message originated from one of
// the additional keys on the enhanced keyboard. The extended keys consist of the ALT and
// CTRL keys on the right-hand side of the keyboard; the INS, DEL, HOME, END, PAGE UP,
// PAGE DOWN, and arrow keys in the clusters to the left of the numeric keypad; the NUM LOCK
// key; the BREAK (CTRL+PAUSE) key; the PRINT SCRN key; and the divide (/) and ENTER keys in
// the numeric keypad. The extended-key flag is set if the key is an extended key.
//
// - docs appear to be incorrect. Use of Spy++ indicates that break is not an extended key.
// Also, menu key and windows keys also appear to be extended.
private static readonly Key[] ExtendedKeys = new Key[] {
Key.RightAlt,
Key.RightCtrl,
Key.NumLock,
Key.Insert,
Key.Delete,
Key.Home,
Key.End,
Key.Prior,
Key.Next,
Key.Up,
Key.Down,
Key.Left,
Key.Right,
Key.Apps,
Key.RWin,
Key.LWin };
// Note that there are no distinct values for the following keys:
// numpad divide
// numpad enter
#endregion
}
}
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