How do I get the current mouse screen coordinates in WPF? - wpf

How to get current mouse coordination on the screen?
I know only Mouse.GetPosition() which get mousePosition of element, but I want to get the coordination without using element.

Or in pure WPF use PointToScreen.
Sample helper method:
// Gets the absolute mouse position, relative to screen
Point GetMousePos() => _window.PointToScreen(Mouse.GetPosition(_window));

To follow up on Rachel's answer.
Here's two ways in which you can get Mouse Screen Coordinates in WPF.
1.Using Windows Forms. Add a reference to System.Windows.Forms
public static Point GetMousePositionWindowsForms()
{
var point = Control.MousePosition;
return new Point(point.X, point.Y);
}
2.Using Win32
[DllImport("user32.dll")]
[return: MarshalAs(UnmanagedType.Bool)]
internal static extern bool GetCursorPos(ref Win32Point pt);
[StructLayout(LayoutKind.Sequential)]
internal struct Win32Point
{
public Int32 X;
public Int32 Y;
};
public static Point GetMousePosition()
{
var w32Mouse = new Win32Point();
GetCursorPos(ref w32Mouse);
return new Point(w32Mouse.X, w32Mouse.Y);
}

Do you want coordinates relative to the screen or the application?
If it's within the application just use:
Mouse.GetPosition(Application.Current.MainWindow);
If not, I believe you can add a reference to System.Windows.Forms and use:
System.Windows.Forms.Control.MousePosition;

If you try a lot of these answers out on different resolutions, computers with multiple monitors, etc. you may find that they don't work reliably. This is because you need to use a transform to get the mouse position relative to the current screen, not the entire viewing area which consists of all your monitors. Something like this...(where "this" is a WPF window).
var transform = PresentationSource.FromVisual(this).CompositionTarget.TransformFromDevice;
var mouse = transform.Transform(GetMousePosition());
public System.Windows.Point GetMousePosition()
{
var point = Forms.Control.MousePosition;
return new Point(point.X, point.Y);
}

This works without having to use forms or import any DLLs:
using System.Windows;
using System.Windows.Input;
/// <summary>
/// Gets the current mouse position on screen
/// </summary>
private Point GetMousePosition()
{
// Position of the mouse relative to the window
var position = Mouse.GetPosition(Window);
// Add the window position
return new Point(position.X + Window.Left, position.Y + Window.Top);
}

You may use combination of TimerDispatcher (WPF Timer analog) and Windows "Hooks" to catch cursor position from operational system.
[DllImport("user32.dll")]
[return: MarshalAs(UnmanagedType.Bool)]
public static extern bool GetCursorPos(out POINT pPoint);
Point is a light struct. It contains only X, Y fields.
public MainWindow()
{
InitializeComponent();
DispatcherTimer dt = new System.Windows.Threading.DispatcherTimer();
dt.Tick += new EventHandler(timer_tick);
dt.Interval = new TimeSpan(0,0,0,0, 50);
dt.Start();
}
private void timer_tick(object sender, EventArgs e)
{
POINT pnt;
GetCursorPos(out pnt);
current_x_box.Text = (pnt.X).ToString();
current_y_box.Text = (pnt.Y).ToString();
}
public struct POINT
{
public int X;
public int Y;
public POINT(int x, int y)
{
this.X = x;
this.Y = y;
}
}
This solution is also resolving the problem with too often or too infrequent parameter reading so you can adjust it by yourself. But remember about WPF method overload with one arg which is representing ticks not milliseconds.
TimeSpan(50); //ticks

If you're looking for a 1 liner, this does well.
new Point(Mouse.GetPosition(mWindow).X + mWindow.Left, Mouse.GetPosition(mWindow).Y + mWindow.Top)
The + mWindow.Left and + mWindow.Top makes sure the position is in the right place even when the user drags the window around.

Mouse.GetPosition(mWindow) gives you the mouse position relative to the parameter of your choice.
mWindow.PointToScreen() convert the position to a point relative to the screen.
So mWindow.PointToScreen(Mouse.GetPosition(mWindow)) gives you the mouse position relative to the screen, assuming that mWindow is a window(actually, any class derived from System.Windows.Media.Visual will have this function), if you are using this inside a WPF window class, this should work.

I wanna use this code
Point PointA;
private void Button_PreviewMouseUp(object sender, MouseButtonEventArgs e) {
PointA = e.MouseDevice.GetPosition(sender as UIElement);
}
private void Button_Click(object sender, RoutedEventArgs e) {
// use PointA Here
}

Related

WPF equivilent of unity 3D's Screen.lockCursor

I haven't used Unity 3D but I gather you can use Screen.lockCursor to take control of the mouse for FPS games. Is this possible in WPF/Win32?
Obviously you have to release it when exiting or in the event of a crash
Thanks
I found the answer spread across a whole bunch of links, so
(1) Set a captureMouse flag, press once to go into this mode, again to come out,
hide the cursor while you are in there
bool captureMouse = false;
private void viewport3D1_MouseDown(object sender, MouseButtonEventArgs e)
{
if (!captureMouse)
{
captureMouse = true;
Mouse.OverrideCursor = Cursors.None;
}
else
{
Mouse.OverrideCursor = null;
captureMouse = false;
}
}
(2) While you're in this mode constantly put the mouse back to the middle of the window
private void theWindow_MouseMove(object sender, MouseEventArgs e)
{
if (!captureMouse)
return;
Point windowPoint = WpfToRealPixels(theWindow, new Point(500, 500));
NativeMethods.SetCursorPos((int)windowPoint.X, (int)windowPoint.Y);
oldP = new Point(500, 500);
}
(3) Translate the co-ords
private Point WpfToRealPixels(Window w, Point p)
{
return theWindow.PointToScreen(p);
}
(4) To put the mouse back you'll need a native Win32 call
public partial class NativeMethods
{
[System.Runtime.InteropServices.DllImportAttribute("user32.dll", EntryPoint = "SetCursorPos")]
[return: System.Runtime.InteropServices.MarshalAsAttribute(System.Runtime.InteropServices.UnmanagedType.Bool)]
public static extern bool SetCursorPos(int X, int Y);
}
Hope that helps someone.

WPF : Move and resize window at once time

In Win32 API, function SetWindowPos provided an easy way to move and resize window at once.
However, in WPF class Window doesn't have a method like SetWindowPos. So I must code like the following:
this.Left += e.HorizontalChange;
this.Top += e.VerticalChange;
this.Width = newWidth;
this.Height = newHeight;
Of course, it works well, but it's not simple. And it looks dirty.
How can i move a window and resize at once?
Is there an API?
I know you've already solved your problem, but I'll post a solution that I found in case it helps others.
Basically, You must declare that SetWindowsPos as an imported function from Win32 this is the signature
[DllImport("user32.dll", CharSet = CharSet.Auto)]
[return: MarshalAs(UnmanagedType.Bool)]
private static extern bool SetWindowPos(IntPtr hWnd, IntPtr hWndInsertAfter, int X, int Y, int cx, int cy, SetWindowPosFlags uFlags);
The function needs the hWnd of your window, in order to get it you can add an handler on the initialization of your windows (for example you could listen for the "SourceInitialized" event) and store that value in a private member of the class:
hwndSource = PresentationSource.FromVisual((Visual)sender) as HwndSource;
WPF manages device independent pixels, so you needs even a converter from dip to real pixel for your screen. This is done with these lines:
var source = PresentationSource.FromVisual(this);
Matrix transformToDevice = source.CompositionTarget.TransformToDevice;
Point[] p = new Point[] { new Point(this.Left + e.HorizontalChange, this.Top), new Point(this.Width - e.HorizontalChange, this.Height) };
transformToDevice.Transform(p);
Finally you can call SetWindowsPos:
SetWindowPos(this.hwndSource.Handle, IntPtr.Zero, Convert.ToInt32(p[0].X), Convert.ToInt32(p[0].Y), Convert.ToInt32(p[1].X), Convert.ToInt32(p[1].Y), SetWindowPosFlags.SWP_SHOWWINDOW);
Sources:
Win32 SetWindowPos
WPF Graphics Rendering
You could wrap your code in a helper method. Just like this:
public static class WindowExtensions {
public static void MoveAndResize( this Window value, double horizontalChange, double verticalChange, double width, double height ) {
value.Left += horizontalChange;
value.Top += verticalChange;
value.Width = width;
value.Height = height;
}
}
So your calling code looks like this:
this.MoveAndResize( 10, 10, 1024, 768 );
I've left off namespace and using declaration, keep that in mind when copying.
Edit:
You could also use the API. Personally I stick with the managed code unless I really need to use the API. But that is up to you.

how to GetMousePosition anywhere on the screen, outside the bounds of window (or any Visual)

I'd like to track the position of the Mouse cursor, in screen coordinates, anywhere on the screen. So even if the mouse cursor moves outside the bounds of the window, is there a way to get the position of the mouse cursor?
What I'm doing is trying to get a popup to follow the mouse cursor, even if it moves off the main window.
Here is a code snippet of what I've tried (and hasn't worked):
private void OnLoaded(object sender, RoutedEventArgs e)
{
bool gotcapture = this.CaptureMouse();
Mouse.AddLostMouseCaptureHandler(this, this.OnMouseLostCapture);
}
Point mouse_position_relative = Mouse.GetPosition(this);
Point mouse_screen_position = popup.PointToScreen(mouse_position_relative);
private void OnMouseLostCapture(object sender, MouseEventArgs e)
{
bool gotcapture = this.CaptureMouse();
this.textblock.Text = "lost capture.";
}
What exactly was your problem?
Wait! There is a way to position a Popup relative to the screen. see PlacementMode.AbsolutePoint
This showed little happy face flying around:
private Popup _popup;
public Window1()
{
InitializeComponent();
this.Loaded += OnLoaded;
}
private void OnLoaded(object sender, RoutedEventArgs e)
{
_popup = new Popup
{
Child = new TextBlock {Text = "=))", Background = Brushes.White},
Placement = PlacementMode.AbsolutePoint,
StaysOpen = true,
IsOpen = true
};
MouseMove += MouseMoveMethod;
CaptureMouse();
}
private void MouseMoveMethod(object sender, MouseEventArgs e)
{
var relativePosition = e.GetPosition(this);
var point= PointToScreen(relativePosition);
_popup.HorizontalOffset = point.X;
_popup.VerticalOffset = point.Y;
}
Never mind, I realized there is no way to position a Popup relative to the screen, only relative to the Visual which contains it.
There are a number of ways to get the screen coordinates of the mouse position outside of a WPF Window. Unfortunately, you'll need to add references to use either of them, but it is possible. You can find examples of them both in #FredrikHedblad's answer to the How do I get the current mouse screen coordinates in WPF? question. Coincidentally, that question was answered a few days before you asked this question and gave up within 21 minutes of asking.

How to draw connecting lines between two controls on a grid WPF

I am creating controls (say button) on a grid. I want to create a connecting line between controls.
Say you you do mousedown on one button and release mouse over another button. This should draw a line between these two buttons.
Can some one help me or give me some ideas on how to do this?
Thanks in advance!
I'm doing something similar; here's a quick summary of what I did:
Drag & Drop
For handling the drag-and-drop between controls there's quite a bit of literature on the web (just search WPF drag-and-drop). The default drag-and-drop implementation is overly complex, IMO, and we ended up using some attached DPs to make it easier (similar to these). Basically, you want a drag method that looks something like this:
private void onMouseLeftButtonDown(object sender, MouseButtonEventArgs e)
{
UIElement element = sender as UIElement;
if (element == null)
return;
DragDrop.DoDragDrop(element, new DataObject(this), DragDropEffects.Move);
}
On the target, set AllowDrop to true, then add an event to Drop:
private void onDrop(object sender, DragEventArgs args)
{
FrameworkElement elem = sender as FrameworkElement;
if (null == elem)
return;
IDataObject data = args.Data;
if (!data.GetDataPresent(typeof(GraphNode))
return;
GraphNode node = data.GetData(typeof(GraphNode)) as GraphNode;
if(null == node)
return;
// ----- Actually do your stuff here -----
}
Drawing the Line
Now for the tricky part! Each control exposes an AnchorPoint DependencyProperty. When the LayoutUpdated event is raised (i.e. when the control moves/resizes/etc), the control recalculates its AnchorPoint. When a connecting line is added, it binds to the DependencyProperties of both the source and destination's AnchorPoints. [EDIT: As Ray Burns pointed out in the comments the Canvas and grid just need to be in the same place; they don't need to be int the same hierarchy (though they may be)]
For updating the position DP:
private void onLayoutUpdated(object sender, EventArgs e)
{
Size size = RenderSize;
Point ofs = new Point(size.Width / 2, isInput ? 0 : size.Height);
AnchorPoint = TransformToVisual(node.canvas).Transform(ofs);
}
For creating the line class (can be done in XAML, too):
public sealed class GraphEdge : UserControl
{
public static readonly DependencyProperty SourceProperty = DependencyProperty.Register("Source", typeof(Point), typeof(GraphEdge), new FrameworkPropertyMetadata(default(Point)));
public Point Source { get { return (Point) this.GetValue(SourceProperty); } set { this.SetValue(SourceProperty, value); } }
public static readonly DependencyProperty DestinationProperty = DependencyProperty.Register("Destination", typeof(Point), typeof(GraphEdge), new FrameworkPropertyMetadata(default(Point)));
public Point Destination { get { return (Point) this.GetValue(DestinationProperty); } set { this.SetValue(DestinationProperty, value); } }
public GraphEdge()
{
LineSegment segment = new LineSegment(default(Point), true);
PathFigure figure = new PathFigure(default(Point), new[] { segment }, false);
PathGeometry geometry = new PathGeometry(new[] { figure });
BindingBase sourceBinding = new Binding {Source = this, Path = new PropertyPath(SourceProperty)};
BindingBase destinationBinding = new Binding { Source = this, Path = new PropertyPath(DestinationProperty) };
BindingOperations.SetBinding(figure, PathFigure.StartPointProperty, sourceBinding);
BindingOperations.SetBinding(segment, LineSegment.PointProperty, destinationBinding);
Content = new Path
{
Data = geometry,
StrokeThickness = 5,
Stroke = Brushes.White,
MinWidth = 1,
MinHeight = 1
};
}
}
If you want to get a lot fancier, you can use a MultiValueBinding on source and destination and add a converter which creates the PathGeometry. Here's an example from GraphSharp. Using this method, you could add arrows to the end of the line, use Bezier curves to make it look more natural, route the line around other controls (though this could be harder than it sounds), etc., etc.
See also
http://social.msdn.microsoft.com/Forums/en-US/wpf/thread/dd246675-bc4e-4d1f-8c04-0571ea51267b
http://www.codeproject.com/KB/WPF/WPFDiagramDesigner_Part1.aspx
http://www.codeproject.com/KB/WPF/WPFDiagramDesigner_Part2.aspx
http://www.codeproject.com/KB/WPF/WPFDiagramDesigner_Part3.aspx
http://www.codeproject.com/KB/WPF/WPFDiagramDesigner_Part4.aspx
http://www.syncfusion.com/products/user-interface-edition/wpf/diagram
http://www.mindscape.co.nz/products/wpfflowdiagrams/

Creating SelectionBorder: Bit in the face by decimal rounding?

I am currently implementing a class called SelectionBorder in WPF. It's derived from the Shape class.
It basically looks like this:
public class SelectionBorder : Shape
{
public Point StartPoint {get; set;}
public PointCollection Points {get; set;}
public double StrokeLength {get; set;}
protected override Geometry DefiningGeometry{
get{
//Magic!
}
}
}
The StartPoint and Points properties determine the corners of the border. The border is a typical stroked line border (one black stroke, one invisible stroke like that: - - - -)
The problem that I have now is that since the corner points are freely choosable it's pretty common that the count of strokes (meaning black and invisible strokes) is not even (in fact not even an integer) and therefore the first stroke looks longer than the others (visible in the picture). This maybe doesn't seem to be a big deal but I later want to animate the border so that the strokes circle round the content. When doing this animation the tiny flaw in the static view becomes clearly visible and in my opinion is highly disturbing.
alt text http://img14.imageshack.us/img14/2874/selectionborder.png
The problem is that I tried to determine a StrokeLength that gets as close to the original StrokeLength as possible and creates an even number of strokes. However the problem I've run into is that WPF (obviously) can't display the whole precision of a double decimal StrokeLength and therefore the resulting stroke number is uneven once again.
Is there any workaround for this problem? Do you probably have another solution for my problem?
Thanks in advance!
EDIT: I retested and reviewed the code after a little break for fitness today and after all it happens only on very big StrokeLengths. I plan to use StrokeLengths of 2 where the little animation jumping does matter much less than I originally thought.
You could make more than one corner "un-matched" in that regard. For example, instead of having one point be the "source" and "destination" of the animated dashes, you could pick 2 points. One would be the "source", dashes appearing to march away from it in 2 directions, and another point be the "destination", where dashes converge and disappear.
GIMP, for example, animates selection dashed lines in this way and seems to pick a point closest to the lower-left for the "source" and a point closest to the upper-right for the "destination".
You could come up with some other scheme, as well.
Just remember that while it may look disturbing to you, most users will not care.
I just found a way that makes it way easier to create such an animated SelectionBorder.
Instead of creating the animation by moving an self-created AnimationPoint through animation I just animated the StrokeDashOffset property natively provided by the Shape class and setting the StrokeDashArray to define the StrokeLength.
It would look like this in XAML:
<namespace:SelectionBorder StrokeDashArray="2" AnimationDuration="0:0:1" Stroke="Black" />
The class looks like this:
public class SelectionBorder : Shape
{
private DoubleAnimation m_Animation;
private bool m_AnimationStarted;
public SelectionBorder()
{
IsVisibleChanged += OnIsVisibleChanged;
}
protected void OnIsVisibleChanged(object sender, DependencyPropertyChangedEventArgs e)
{
if (Visibility == Visibility.Visible)
{
StartAnimation();
}
else
{
StopAnimation();
}
}
public void StartAnimation()
{
if (m_AnimationStarted)
return;
if (m_Animation == null)
{
m_Animation = CreateAnimation();
}
BeginAnimation(StrokeDashOffsetProperty, m_Animation);
m_AnimationStarted = true;
}
protected virtual DoubleAnimation CreateAnimation()
{
DoubleAnimation animation = new DoubleAnimation();
animation.From = 0;
if (StrokeDashArray.Count == 0)
animation.To = 4;
else
animation.To = StrokeDashArray.First() * 2;
animation.Duration = AnimationDuration;
animation.RepeatBehavior = RepeatBehavior.Forever;
return animation;
}
public void StopAnimation()
{
if (m_AnimationStarted)
{
BeginAnimation(StrokeDashOffsetProperty, null);
m_AnimationStarted = false;
}
}
#region Dependency Properties
public Duration AnimationDuration
{
get { return (Duration)GetValue(AnimationDurationProperty); }
set { SetValue(AnimationDurationProperty, value); }
}
public static readonly DependencyProperty AnimationDurationProperty =
DependencyProperty.Register("AnimationDuration", typeof(Duration), typeof(SelectionBorder), new UIPropertyMetadata(new Duration(TimeSpan.FromSeconds(0.5))));
#endregion Dependency Properties
protected override Geometry DefiningGeometry
{
get
{
double width = (double.IsNaN(Width)) ? ((Panel)Parent).ActualWidth : Width;
double height = (double.IsNaN(Height)) ? ((Panel)Parent).ActualHeight : Height;
RectangleGeometry geometry = new RectangleGeometry(new Rect(0, 0, width, height));
return geometry;
}
}
}

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