Develop Reference

Visual Studio C# how to move a button's X position by mouse without flicker

So I'm trying to make a slider. I'm using my cursor to move a button's x position.
I have 3 functions, the mouseDown, mouseUp and the mouseMove function. In the mouseUp and mouseDown functions I set a variable to true and false to tell the program that the mouse is clicked or not. In the mouseMove function I tell the program to set the button's x position to the x position of the mouse when the mouse is clicked. This works but has 2 problems.
The first problem is that when I press the button and move it, the button moves along with the mouse's x but it has a space between the mouse and the button. It looks a bit like this:
CURSOR.......BUTTON
The space between the cursor and button change when I change the resolution of the form.
The second problem is that when I move the button it flickers a bit. It only does this at higher speeds but it is a problem in my case.
My code looks like this:
bool mouseDown = false;
private void volumeGrabBT_MouseDown(object sender, MouseEventArgs e)
{
if (e.Button == MouseButtons.Left)
{
mouseDown = true;
}
}
private void volumeGrabBT_MouseUp(object sender, MouseEventArgs e)
{
if (e.Button == MouseButtons.Left)
{
mouseDown = false;
}
}
private void volumeGrabBT_MouseMove(object sender, MouseEventArgs e)
{
if (mouseDown == true)
{
Point volumeBTPoint = new Point();
volumeBTPoint.X = Cursor.Position.X;
volumeBTPoint.Y = volumeGrabBT.Location.Y;
volumeGrabBT.Location = volumeBTPoint;
}
}
The volumeGrabBT is the button I'm trying to move along with the mouse.
The volumeBTPoint is the point of the button I'm trying to set the button's position to.
I hope someone can help me fix these problems. Thanks in advance!

I believe that flickering can be fixed by setting some additional form styles: SetStyle(ControlStyles.AllPaintingInWmPaint |ControlStyles.UserPaint | ControlStyles.DoubleBuffer, true);
in form's constructor. It will use double buffering and generally just draws faster.
For the Cursor class, it's relative to the screen, not your form. You can use this.PointToClient() function to get client's space position of cursor, like this:
Point clientCursor = this.PointToClient(Cursor.Position);
and then use clientCursor to get exact X in your client space.

You have to translate screen coordinates to client coordinates.
Point volumeBTPoint = new Point();
Point point = this.PointToClient(Cursor.Position);
volumeBTPoint.X = point.X;
volumeBTPoint.Y = volumeGrabBT.Location.Y;
volumeGrabBT.Location = volumeBTPoint;
Instead of this you should use button's parent control (Panel, GroupBox, etc).

How to get the correct position of an Image in WPF?

I am a beginner in Windows Presentation Foundation.
I have a Canvas in which there is a small square canvas. Inside this small square canvas i have an image.
I have attached an event handler to this image , When user click on this image user can get the current position of the image.
Whenever user click on that image , he/she will get a prompt message box in which user get the current image position to print.
Everything is working fine when user press Left click on the image .
But, the problem arises when user first pressing the right click on the image and suddenly pressing Left click on the same image , It is not showing the same value.
I have not attached any event handler on the right click.
I am using the following code :
Image objImage = new Image();
objImage .Height =12;
objImage .Width = 12;
objImage .Stretch = Stretch.UniformToFill;
imageAck.MouseLeftButtonDown += new MouseButtonEventHandler(objImageMouseLeftButtonDown);
private void objImageMouseLeftButtonDown(object sender, MouseButtonEventArgs e)
{
Point mouseCurrent = e.GetPosition(null);
}
I am notgetting the same value in mouseCurrent

Using e.GetPosition, this gets the position of the mouse pointer relative to the element that was clicked, not the canvas that the element belongs to.
To get the actual position of the image on the Canvas, you need to use the Canvas.GetLeft, and Canvas.GetTop methods. Here is an example:
private void objImageMouseLeftButtonDown(object sender, MouseButtonEventArgs e)
{
double left = Canvas.GetLeft((UIElement)sender);
double top = Canvas.GetTop((UIElement)sender);
}
You can then use the left and top variables for whatever purpose you need.

Finally, I got an answer by Googling some hour .....
Point currentMousePosition = Mouse.GetPosition(Application.Current.MainWindow);

Drag Ovalshape across form

So I have a bit of a problem with moving Ovalshapes around a form. The goal is to have a circle move within the bounds of two other circles, one placed inside the other and the moving circle essentially moving around them.
I am having trouble moving the circle with the mouse. Whenever I click and hold the circle, the circle moves to the coordinates of the location I clicked on the circle, such that if I click in the middle of an Ovalshape of size 10, it would set the circle's location to (5,5).
Here is what I have:
public partial class Form1 : Form
{
int smallRadius;
int largeRadius;
int movingRadius;
int distanceFromCenterToLocation;
bool mouseDown;
Point movingCenter;
Point returnPoint;
public Form1()
{
mouseDown = false;
InitializeComponent();
smallRadius = (ovalShape1.Right - ovalShape1.Left) / 2;
largeRadius = (ovalShape2.Right - ovalShape2.Left) / 2;
Point center = new Point(ovalShape1.Left + smallRadius, ovalShape1.Top + smallRadius);
ovalShape3.Height = largeRadius - smallRadius;
ovalShape3.Width = largeRadius - smallRadius;
movingRadius = (ovalShape3.Right - ovalShape3.Left) / 2;
ovalShape3.Location = new Point(center.X - (movingRadius), center.Y - largeRadius);
movingCenter = new Point(ovalShape3.Left + movingRadius, ovalShape3.Top + movingRadius);
distanceFromCenterToLocation = Convert.ToInt32(Math.Sqrt(Math.Pow(movingRadius, 2.0) + Math.Pow(movingRadius, 2.0)));
int middleRadius = center.X - movingCenter.X;
}
private void ovalShape3_MouseUp(object sender, MouseEventArgs e)
{
mouseDown = false;
}
private void ovalShape3_MouseDown(object sender, MouseEventArgs e)
{
mouseDown = true;
}
private void ovalShape3_MouseMove(object sender, MouseEventArgs e)
{
if (mouseDown)
{
ovalShape3.Location = e.Location;
}
}
}

For some reason OvalShape isn't derived from Control and doesn't behave like a control.
When a control receives a mouse event the Location property of the MouseEventArgs holds the coordinates relative to the upper-left corner of the form. Shapes however receive the coordinates relative to their own upper-left corner.
When a mouse button is pressed over a control it will capture the mouse so that subsequent events are sent to the same control until you release the button. Shapes only receive mouse events if the mouse is over the shape no matter if a mouse button is pressed. Once you move the mouse to the top or left the shape doesn't receive any mouse events. Therefore the shape doesn't follow the mouse and also the MouseUp event is not handled.
All shapes in a form are embedded in a single control of type ShapeContainer. This is created automatically when you add a shape to a form in the Visual Studio designer. To get the expected behavior you need to find that ShapeContainer (probably called shapeContainer1) and handle its mouse events instead:
public Form1()
{
InitializeComponent();
// do your initialization
...
// assign the events to the ShapeContainer
// don't forget to remove the handlers from ovalShape3 in the designer!!!
ShapeContainer container = ovalShape3.Parent;
container.MouseUp += ovalShape3_MouseUp;
container.MouseDown += ovalShape3_MouseDown;
container.MouseMove += ovalShape3_MouseMove;
}

get cursor position

I have an usercontrol called TaskControl and a button for creating other usercontrols by dragging. I want the new user control that appears to be at the same coordinates where my cursor is. Below it is my code. It doesn't want to appear at those coordinates and the new usercontrol appears behind the old one.
My code:
private void button1_Click(object sender, EventArgs e)
{
Point localCoordinates = this.PointToClient(Cursor.Position);
TaskControl t = new TaskControl();
t.Location = new Point(Cursor.Position.X,Cursor.Position.Y);
t.MouseDown += new MouseEventHandler(t_MouseDown);
t.MouseMove += new MouseEventHandler(t_MouseMove);
t.MouseUp += new MouseEventHandler(t_MouseUp);
this.Controls.Add(t);
}

You have to work out that using Control.MousePosition static property, which
Gets the position of the mouse cursor in screen coordinates.
After move your use control to the coordinates retrived. Please note, that depends on how you architect your UI, you may need to convert coordinates to client. For this can use
Control.PointToClient static method, which:
Computes the location of the specified screen point into client
coordinates.

Take a look Control.MousePosition
Gets the position of the mouse cursor in screen coordinates.

Winform - determine if mouse has left user control

I am struggling with something that I think should be easily (ish). I have a windows form and a flowgridlayout panel at the bottom of the form. Inside this form I dynamically populate it with X number of User Controls. The controls are all the same type.
The goal is when the user hoovers the mouse over the user control it opens another form and positions it where the mouse is. When mouse leaves the form the opened form disappears.
This almost works great. The problem is when the User Control has anything like a label or text box inside it. It is considered to have left the UC so the form disappears.
My thought was then to use the X and Y to tell if it is inside the UC but I can not figure this out.
Can I ask:
1) What is the best approach to this?
2) How can I code it, as the UC's are dynamic I can not know exactly where they will be.
Thanks
EDIT
I am trying to figure out the mouse pointers but not getting there. The code below is within the UC SmallTagBox_MouseLeave event:
Point loc = this.Location;
Point p = this.PointToScreen(this.Location);
Point p2 = this.PointToScreen(this.Parent.Location);
Point ms = MousePosition;
Rectangle screenBounds = new Rectangle(this.PointToScreen(this.Location), this.Size);
if (!screenBounds.Contains(ms))
{
thw.Close();
thw = null;
}
loc {X = 275 Y = 3} System.Drawing.Point
p {X = 808 Y = 908} System.Drawing.Point
p {X = 808 Y = 908} System.Drawing.Point
p2 {X = 545 Y = 1542} System.Drawing.Point
ms {X = 574 Y = 914} System.Drawing.Point
screenBounds {X = 808 Y = 908 Width = 62 Height = 29} System.Drawing.Rectangle
I do not understand how p2 (its parent) can have a greater Y value relative to the screen.

Hooking all the controls MouseEnter and MouseLeave events, then figuring out if it is still inside the form is pretty painful. A simple timer can get the job done too:
public partial class Form1 : Form {
private Timer mTimer;
public Form1() {
InitializeComponent();
mTimer = new Timer();
mTimer.Interval = 200;
mTimer.Tick += mTimer_Tick;
mTimer.Enabled = true;
}
private void mTimer_Tick(object sender, EventArgs e) {
if (!this.DesktopBounds.Contains(Cursor.Position)) this.Close();
}
}

Idea 1) When the MouseLeave event fires, you can check the mouse coordinates (relative to screen) and check if they're still within the bounds of your usercontrol. If they are, it should be assumed that the mouse has to pass back through the control to get outside the bounds, and you can safely ignore the event this time.
Idea 2) Attach MouseEnter event handlers to the child controls. Then when the mouse enters one, you will know and can ignore the usercontrol's MouseLeave event. Then when the child's MouseLeave event fires, check for the usercontrol's MouseEnter again.

I think I would add an event handler for MouseLeave for every control that you have and use the Parent property to find the User Control you are after. I agree, it will be a bit painful though.

You can also loop through all the child controls (recursive) on your control, and attach a MouseEnter and MouseLeave event to them as well.
You have to do some bookkeeping if the mouse is in your control, or some child control.