Listbox events firing strangely - c#

I'm confused. I am basically trying to tell when the user has clicked something in the listbox, held the button, and left the listbox. Here is a somewhat dumbed down version of what I am doing:
private bool itemHeld;
private void listOriginal_MouseDown(object sender, MouseEventArgs e)
{
itemHeld = true;
}
private void listOriginal_MouseUp(object sender, MouseEventArgs e)
{
itemHeld = false;
}
private void listOriginal_MouseLeave(object sender, EventArgs e)
{
if (itemHeld)
MessageBox.Show("OHH YEAH");
}
To me that seems like it should turn itemHeld true when you press the mousebutton, turn it false only if you lift it, and display ohh yeah if the value is true. If I break on the mouse down event to check the value, it is true and if I continue from there it displays the message. If I do not break, it does nothing. Is there something else at work here?
Edit:
Brief description: It would be difficult to explain what I am really trying to accomplish but imagine something almost like dragging a file off of a window. I need to simply be able to recognize when the user clicks inside of the listbox and then drags out of the listbox if that makes sense

You can not debug windows events by break point because when the Visual Studio get active to debug, the mouse leave event will be fired for the hovered control.
You can use Debug.WriteLine which writes information about the debug to the trace listeners.
private void button1_MouseLeave(object sender, EventArgs e)
{
Debug.WriteLine("Mouse leave");
}
private void button1_MouseEnter(object sender, EventArgs e)
{
Debug.WriteLine("Mouse enter");
}
private void button1_MouseHover(object sender, EventArgs e)
{
Debug.WriteLine("Mouse hover");
}

what about this?
private void listBox1_MouseMove(object sender, MouseEventArgs e)
{
if (e.X > listBox1.Width - 1 || e.Y > listBox1.Height - 1 || e.X < 0 || e.Y < 0)
{
Console.WriteLine("drag out");
}
else
Console.WriteLine("mouse move {0}/{1}", e.X, e.Y);
}
it uses the fact that the Control is not left before the mousebutton is released ... but be aware that the drag out part will occur more than once so you probably will want to have a flag set the first time ... and have that flag cleared on mouse up or leave

For every mouse click, your MouseDown event will fire AND your MouseUp event will fire, so the sequence of operations is equivalent to
itemHeld = true;
itemHeld = false;
if(itemHeld)
MessageBox.Show("yay");
If you press the mouse button on the listbox and move the cursor out without releasing the button, switching focus to another window (e.g. Visual Studio) is what triggers the MouseLeave event to fire. This is why you're seeing the message box pop up when you're debugging.
I'm not sure what you're trying to accomplish, so I can't recommend another solution.

Related

C# Form - MouseClick will click the actual control after losing form focus

If you ever remove focus from any professional application like Chrome/FireFox/Visual Studio, and then reclick a button/menu item, it will actually click it as if you never lost focus.
How can I apply the same concept in C# WinForm? I tried many things like
private void form1_MouseClick(object sender, MouseEventArgs e)
{
BringToFront();
Activate();
}
Activate/focus/select/etc... nothing worked to react the same way, it always takes 3-4 clicks to actually click on a menu!
I thought about making a click event for every single control, but that seemed rather redundant.
Check this for example (Yellow Clicks)
You are right about Menues taking an extra click to get focus.
Which is extra annoying since the menue get highlighted anyway but doesn't react to the 1st click..
You can avoid that by coding the MouseEnter event:
private void menuStrip1_MouseEnter(object sender, EventArgs e)
{
// either
menuStrip1.Focus();
// or
this.Focus();
}
The downside of this is, that it is stealing focus from other applications, which is not something a well-behaved application should do..
So I think it is better to wait for a definitive user action; code the MouseDown event in a similar way..:
private void menuStrip1_MouseDown(object sender, MouseEventArgs e)
{
menuStrip1.Focus();
}
Or use the event that was made for the occasion:
private void menuStrip1_MenuActivate(object sender, EventArgs e)
{
menuStrip1.Focus();
}
I can't confirm a similar problem with Buttons or any other controls, though.
I have find trick to solve your problem. it work for me 100%
See this code:
dynamic elem1;
private void menuStrip1_MouseEnter(object sender, EventArgs e)
{
elem1 = sender;
}
private void menuStrip1_MouseLeave(object sender, EventArgs e)
{
elem1 = null;
}
private void Form1_Activated(object sender, EventArgs e)
{
if(elem1 != null){
elem1.PerformClick();
if (elem1.GetType().ToString() == "System.Windows.Forms.ToolStripMenuItem") elem1.ShowDropDown();
}
elem1 = null;
}
Here what happend.
When mouse enter button/menu item elem1 = this button/menu, and when mouse leave it set back to null.
so when form Activated we can call elem1.PerformClick() to click the button/menu item.

Mouse events for captured element stop firing while dragging

I have some code that draws some points on the screen and then allows them to be dragged while holding the left mouse button. This kinda works except constantly the mouse events stop firing and the point being dragged stops moving.
Because all of the events stop being caught(for some unknown reason), that means the user can release the left mouse button without anything happening.
The weird thing is that the user can then reposition the mouse over the point and it will start dragging again without holding the left mouse button down. It makes for a very poor user experience.
What is going on?
pinPoint.MouseLeftButtonDown += Point_MouseLeftButtonDown;
pinPoint.MouseLeftButtonUp += Point_MouseLeftButtonUp;
pinPoint.MouseMove += Point_MouseMove;
.
.
.
void Point_MouseLeftButtonDown(object sender, MouseButtonEventArgs e)
{
((UIElement)sender).CaptureMouse();
if (_isDragging == false)
{
_isDragging = true;
}
}
void Point_MouseLeftButtonUp(object sender, MouseButtonEventArgs e)
{
_isDragging = false;
((UIElement)sender).ReleaseMouseCapture();
}
void Point_MouseMove(object sender, MouseEventArgs e)
{
//where the point gets moved and some other logic
//possibly this logic takes too long?
}
I've found a solution that works. I've still got no idea why it is continually losing the MouseCapture though.
pinPoint.LostMouseCapture += Point_LostMouseCapture;
.
.
.
void Point_LostMouseCapture(object sender, MouseEventArgs e)
{
//if we lost the capture but we are still dragging then just recapture it
if (_isDragging)
{
((UIElement)sender).CaptureMouse();
}
}

DoDragDrop Stop/Cancel?

Forgive the rather poor code here.
I have a picture box PictureBox and a section Panel. I am trying to start a drag and drop operation so you click and drag the picture box, and dropping it into the Section creates a copy. This is fine.
But the problem is, lets say you click the picture box 9 times, no drag, just clicks. Then on the 10th turn, you do a correct drag and drop operation.... Then you get 10 duplicates added to the Section.
I am guessing that I need to respond to when a DragAndDrop is invalid and stop the drag and drop operation to prevent these duplicate buildups, but I do not know where to look to achieve this.
private void collectablePictureBox_MouseDown(object sender, MouseEventArgs e)
{
this.SelectedSection.AllowDrop = true;
this.SelectedSection.DragEnter += new DragEventHandler(this.CollectableSelectedSection_DragEnter);
this.SelectedSection.DragDrop += new DragEventHandler(this.CollectableSelectedSection_DragDrop);
this.collectablePictureBox.DoDragDrop(this.SelectedClassModel, DragDropEffects.Copy);
}
private void CollectablePictureBox_QueryContinueDrag(object sender, QueryContinueDragEventArgs e)
{
Console.WriteLine(e.Action);
}
private void CollectableSelectedSection_DragEnter(object sender, DragEventArgs e)
{
e.Effect = DragDropEffects.Copy;
}
private void CollectableSelectedSection_DragDrop(object sender, DragEventArgs e)
{
Point position = this.SelectedSection.PointToClient(new Point(e.X, e.Y));
position.X -= this.SelectedClassModel.Width >> 1;
position.Y -= this.SelectedClassModel.Height >> 1;
this.SelectedSection.AllowDrop = false;
this.SelectedSection.DragEnter -= this.CollectableSelectedSection_DragEnter;
this.SelectedSection.DragDrop -= this.CollectableSelectedSection_DragDrop;
this.SelectedSection.AddItem(this.SelectedClassModel, position, this.SectionCanvasSnapToGridCheckBox.Checked);
}
Your problem comes from the fact that on every MouseDown event you add handlers to the appropriate events, so when you actually do the Drag and Drop those handlers will be called more than once. Currently I see two different ways of solving this:
One way to solve the problem would be to not start the Drag and Drop on the MouseDown event handler, but - based on this MSDN article - start it in a MouseMove handler instead, like this:
private void collectablePictureBox_MouseMove(object sender, MouseEventArgs e)
{
if (sender != null && e.LeftButton == MouseButtonState.Pressed)
{
this.SelectedSection.AllowDrop = true;
this.SelectedSection.DragEnter += new DragEventHandler(this.CollectableSelectedSection_DragEnter);
this.SelectedSection.DragDrop += new DragEventHandler(this.CollectableSelectedSection_DragDrop);
this.collectablePictureBox.DoDragDrop(this.SelectedClassModel, DragDropEffects.Copy);
}
}
Another way would be to also handle the MouseUp event of the PictureBox, and do a similar cleanup as in your CollectableSelectedSection_DragDrop handler.

Did "MouseUp" event change value of NumericUpDown?

I need to determine if the value of a NumericUpDown control was changed by a mouseUp event.
I need to call an expensive function when the value of a numericupdown has changed. I can't just use "ValueChanged", I need to use MouseUp and KeyUp events.
Basically, I need to know:
Did the value of the numericUpDown change when the user let go of the
mouse? If any area which is not highlighted in red is clicked, the
answer is no. I need to IGNORE the mouse up event, when ANYWHERE but the red area is clicked.
How can I determine this by code? I find events a little confusing.
This will fire when the user releases the mouse button. You might want to investigate which mousebutton was released.
EDIT
decimal numvalue = 0;
private void numericUpDown1_MouseUp(object sender, MouseEventArgs e)
{
if (e.Button == MouseButtons.Left && numvalue != numericUpDown1.Value)
{
//expensive routines
MessageBox.Show(numericUpDown1.Value.ToString());
}
numvalue = numericUpDown1.Value;
}
EDIT 2
This will determine if the left mousebutton is still down, if it is exit before performing expensive routine, doesn't help with keyboard button down.
private void numericUpDown1_ValueChanged(object sender, EventArgs e)
{
if ((Control.MouseButtons & MouseButtons.Left) == MouseButtons.Left)
{
return;
}
//expensive routines
}
Edit 3
How to detect the currently pressed key?
Will help solve the Any key down, Though I think the only ones that matter are the arrow keys
Problem - I need to IGNORE the mouse up event, when ANYWHERE but the red area is clicked.
Derive a custom numeric control as shown below. Get the TextArea of the Numeric Control and ignore the KeyUp.
class UpDownLabel : NumericUpDown
{
private Label mLabel;
private TextBox mBox;
public UpDownLabel()
{
mBox = this.Controls[1] as TextBox;
mBox.Enabled = false;
mLabel = new Label();
mLabel.Location = mBox.Location;
mLabel.Size = mBox.Size;
this.Controls.Add(mLabel);
mLabel.BringToFront();
mLabel.MouseUp += new MouseEventHandler(mLabel_MouseUp);
}
// ignore the KeyUp event in the textarea
void mLabel_MouseUp(object sender, MouseEventArgs e)
{
return;
}
protected override void UpdateEditText()
{
base.UpdateEditText();
if (mLabel != null) mLabel.Text = mBox.Text;
}
}
In the MainForm, update your designer with this control i.e. UpDownLabel:-
private void numericUpDown1_MouseUp(object sender, MouseEventArgs e)
{
MessageBox.Show("From Up/Down");
}
Referred from - https://stackoverflow.com/a/4059473/763026 & handled the MouseUp event.
Now, use this control instead of the standard one and hook on the
KeyUp event. You will always get the KeyUp event from the Up/Down button only i.e. RED AREA when you click the
spinner [Up/Down button, which is again a different control derived
from UpDownBase].
I think you should use Leave event that when the focus of NumericUpDown control gone, it would called.
int x = 0;
private void numericUpDown1_Leave(object sender, EventArgs e)
{
x++;
label1.Text = x.ToString();
}

Creating A Continuous Action During A Windows Form Mouse Event

When I put a button on a form in C#, Visual Studio 2005, and have an action triggered by a button event, such as MouseHover or MouseDown, then the event triggers a single call to the function which defines the action despite the fact that I may continue to hover or keep the left button down. In this case I am trying to move a graphical object by rotating or translating it. I don't want to continue to click the mouse in order to get a repeated call to the transforming function, just keep the mouse hovering or hold the button down. What maintains the action until I cease my own action?
Set a flag on MouseEnter and keep doing the action while the flag remains true. Set the flag to false on MouseLeave.
In your case you need to use a combination of the events MouseDown, MouseMove and MouseUp.
Here a small simplified example to start:
private void OnMouseDown(object sender, EventArgs e)
{
//hit test to check if the mouse pointer is on a graphical object
_myHitObject = the_selected_object
}
private void OnMouseMove(object sender, EventArgs e)
{
if(_myHitObject != null)
//do your action relative to the mouse movements.
}
private void OnMouseUp(object sender, EventArgs e)
{
_myHitObject = null;
}
The solution is to use DoEvents() which allows for the MouseLeave event to be noted and the class variable "more" to be changed:
private void MouseEnter_ZoomIn(object sender, EventArgs e)
{
more = true;
while (more == true)
{
c1Chart3D1.ChartArea.View.ViewportScale *= ZoomMultiple;
Application.DoEvents();
}
} // MOUSEENTER_ZOOMIN()
//-------------------------------------
private void MouseLeave_Stop(object sender, EventArgs e)
{
more = false;
}

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