Develop Reference

Dragging Objects in C#

I am attempting to drag Music Notes vertically, up and down a Music Staff. However, rather than a constant drag, I would like the music notes to only be allowed to be dragged onto particular intervals (only specific y-coordinates). For example, in a vertical line, a music note can be dragged on to coordinates (0,0), (0,5) or (0,10).
Below is my relevant code:
private Point MouseDownLocation;
private void Note_MouseDown(object sender, MouseEventArgs e)
{
foreach (MusicNote mn in panel2.Controls.OfType<MusicNote>())
{
if (sender == mn)
{
if (e.Button == MouseButtons.Left)
{
MouseDownLocation = e.Location;
}
}
}
}
private void Note_MouseMove(object sender, MouseEventArgs e)
{
foreach(MusicNote mn in panel2.Controls.OfType<MusicNote>())
{
if (sender == mn)
{
if (e.Button == MouseButtons.Left)
{
mn.Top = e.Y + mn.Top - MouseDownLocation.Y;
}
}
}
}
Any help is appreciated. Thank you!

Basically, you need to check if you drag up or drag down
You should want to check the MouseDown.X and compare it to the MouseUp.X (or Y if you want to check vertical direction as well). It is important to note that (0, 0) is the upper left of your screen. So you need to compare the X position from mouse down event to the mouse up event.
here's an example with one label that moves up and down in steps of 10
private void label1_MouseDown(object sender, MouseEventArgs e)
{
if (e.Button == System.Windows.Forms.MouseButtons.Left)
{
if (label1.Location.Y > 0 && label1.Location.Y < panel1.Size.Height) // not the most accurate way, but you get the idea
{
mPointDown = new Point(e.X, e.Y);
}
}
}
private void label1_MouseUp(object sender, MouseEventArgs e)
{
bool movedUp, movedDown;
if (e.Y == mPointDown.Y)
{
movedUp = movedDown = false;
}
else
{
movedUp = e.Y < mPointDown.Y;
movedDown = !movedUp;
}
if (movedDown)
{
label1.Location = new Point(label1.Location.X, label1.Location.Y + 10);
}
else if (movedUp)
{
label1.Location = new Point(label1.Location.X, label1.Location.Y - 10);
}
}
private void label1_MouseMove(object sender, MouseEventArgs e)
{
mouseDownPoint = e.Location;
}

How to move a pictureBox inside a Panel by Mouse

How to move a pictureBox inside a Panel by Mouse.
Visual Studio 2015 C# Winsows Forms Application.
I've made a primitive slider to control the volume of my WindowsMediaPlayer.
A panel as the background and a pictureBox inside as the slider-knopf.
And it works well.
But purely visually it does not work that good.
I'v searched all around, but can't I find an answer to this little funny problem.
Here is my code:
int posY;
private void pictureBox1_MouseDown(object sender, MouseEventArgs e)
{
if (e.Button == MouseButtons.Left)
{
posY = e.Y; ;
}
}
private void pictureBox1_MouseMove(object sender, MouseEventArgs e)
{
PictureBox box = sender as PictureBox;
if (e.Button == MouseButtons.Left)
{
box.Top += e.Y - posY;
}
if (box.Top < 0)
{
box.Top = 0;
}
if (box.Top > 100)
{
box.Top = 100;
}
int n = box.Top;
n = n * - 1 + 100;
label1.Text = n.ToString();
}
When I move the pictureBox out of the edge of the little panel, the pictureBox somehow 'shrinks' in the panel.
But when I release the mouse, the pictureBox restore its size.
Slider.gif
Why is that.?
And how can I avoid it.?
Thanks.

I found a solution.
It's not optimal, but it can be used.
I changed the code to:
private void pictureBox1_MouseDown(object sender, MouseEventArgs e)
{
if (e.Button == MouseButtons.Left)
{
dragging = true;
startPoint = e.Location;
}
}
private void pictureBox1_MouseMove(object sender, MouseEventArgs e)
{
if (dragging)
{
Debug.WriteLine("mousemove X: " + e.X + " Y: " + e.Y);
pictureBox1.Location = new Point(0, pictureBox1.Top + e.Location.Y - startPoint.Y);
if (pictureBox1.Location.Y < 0)
{
pictureBox1.Location = new Point(0, 0);
dragging = false;
}
if (pictureBox1.Location.Y > 100)
{
pictureBox1.Location = new Point(0, 100);
dragging = false;
}
this.Refresh();
}
int n = pictureBox1.Location.Y;
n = n * -1 + 100;
label1.Text = n.ToString();
mediaPlayer1.settings.volume = n;
}
private void pictureBox1_MouseUp(object sender, MouseEventArgs e)
{
dragging = false;
}
gif
I still need to put an 'if' to correct, when the pictureBox1 is pulled out of the panel.
And to avoid flicker, I have had to put a 'dragging = false'.
However, it results in the pictureBox1 is getting frozen to the edge, so I have to release the mouse, and re-click to continue.
But well - it's to live with.
Thanks.

Panning of a map is not smooth in winforms

Combining the multiple small images *(256*256)* into a large image(dimensions of picturebox). Now if I am trying to pan / move the large image it is not moving until the difference is 256 pixels. Its not panning smoothly. Here is my code
private void pictureBox1_MouseMove(object sender, MouseEventArgs e)
{
if (e.Button == MouseButtons.Right)
{
if (isdragging)
{
mapCenterX += (-e.X + (startingpoint.X)) * Map.scaleX;
mapCenterY -= (-e.Y + (startingpoint.Y)) * Map.scaleY;
Map.DrawMap(mapCenterX, mapCenterY, mapZoom);
startingpoint.X = e.X;
startingpoint.Y = e.Y;
pictureBox1.Invalidate();
}
}
}
private void pictureBox1_MouseUp(object sender, MouseEventArgs e)
{
if (e.Button == MouseButtons.Right)
{
isdragging = false;
}
}
private void pictureBox1_MouseDown(object sender, MouseEventArgs e)
{
if (e.Button == MouseButtons.Right)
{
isdragging = true;
startingpoint.X = e.X;
startingpoint.Y = e.Y;
}
}

Windows Forms:picture box manual drag operation over image solution?

Hi I write a code that will dragginging picture box in winform this is my code:
private void pictureBox1_MouseUp(object sender, MouseEventArgs e)
{
pictureBox1.Top=(56 * ((pictureBox1.Top + (e.Y - firsty)) / 56) + 3); //this for the correction of location of picture box
isdragging[0] = false;
}
private void pictureBox1_MouseDown(object sender, MouseEventArgs e)
{
isdragging[0] = true;
firstx = e.X;
firsty = e.Y;
changeclickingstatus(pictureBox1);//this about my program
for (sbyte i = 0; i < (sbyte)20; i++)//this about my program
{
clickindex[i] = (sbyte)1;//this about my program
}
clickindex[0] = (sbyte)0;//this about my program
dragtop = (sbyte)(pictureBox1.Top/56);//this about my program
}
private void pictureBox1_MouseMove(object sender, MouseEventArgs e)
{
if (isdragging[0])
{
if (pictureBox1.Location.Y + (e.Y - firsty) < 0)
{
pictureBox1.Top = 0;//these are the limits of dragging
}
else if (pictureBox1.Location.Y + (e.Y - firsty) > 290)
{
pictureBox1.Top = 290;//these are the limits of dragging
}
else
{
pictureBox1.Top = pictureBox1.Top + (e.Y - firsty);
}
if (pictureBox1.Location.X + (e.X - firstx) < 6)
{
pictureBox1.Left = 6;//these are the limits of dragging
}
else if (pictureBox1.Location.X + (e.X - firstx) > 280)
{
pictureBox1.Left = 280;//these are the limits of dragging
}
else
{
pictureBox1.Left = pictureBox1.Left + (e.X - firstx);
}
}
}
and I have same code for picturebox 2, my question is:
when I am dragging my first picture to second one it goes over it and code work properly,but while ı am dragging second picture box to first picture box , second picture box goes under the first one ! is there a property for this?

You can use BringToFront() method:
private void pictureBox1_MouseDown(object sender, MouseEventArgs e)
{
pictureBox1.BringToFront();
/**/
}
private void pictureBox2_MouseDown(object sender, MouseEventArgs e)
{
pictureBox2.BringToFront();
/**/
}

Move form relative to location clicked

I have a form which can be moved when the user clicks and drags in a border area. The implementations I've seen all lock to the current mouse position, so that when the form is moved, the form jumps so that the mouse is in the upper-left corner. I'd like to change it so that it behaves like a normal windows form, and the form stays at the same position relative to the mouse when moved. My current code looks like this:
Point locationClicked;
bool isMouseDown = false;
private void Form1_MouseDown(object sender, MouseEventArgs e)
{
isMouseDown = true;
locationClicked = new Point(e.Location.X, e.Location.Y);
}
private void Form1_MouseUp(object sender, MouseEventArgs e)
{
isMouseDown = false;
}
private void Form1_MouseMove(object sender, MouseEventArgs e)
{
if (isMouseDown && targetCell == new Point(-1, -1) && (mouseLocation.X < margin.X || mouseLocation.Y < margin.Y ||
mouseLocation.X > margin.X + cellSize.Width * gridSize.Width ||
mouseLocation.Y > margin.Y + cellSize.Height * gridSize.Height))
{
this.Location = new Point(e.Location.X - locationClicked.X, e.Location.Y - locationClicked.Y);
}
}
When I drag the window, it behaves similarly to what I want. The form flickers between two locations on the screen, one of which moves at about half the rate of the mouse. Is there a way I can fix this?

Try this out...
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
Point locationClicked;
bool dragForm = false;
private void Form1_MouseDown(object sender, MouseEventArgs e)
{
if (e.Button == System.Windows.Forms.MouseButtons.Left)
{
locationClicked = new Point(e.Location.X, e.Location.Y);
if (isMouseDown && targetCell == new Point(-1, -1) && (mouseLocation.X < margin.X || mouseLocation.Y < margin.Y ||
mouseLocation.X > margin.X + cellSize.Width * gridSize.Width ||
mouseLocation.Y > margin.Y + cellSize.Height * gridSize.Height))
{
dragForm = true;
}
}
}
private void Form1_MouseMove(object sender, MouseEventArgs e)
{
if (dragForm)
{
this.Location = new Point(this.Location.X + (e.X - locationClicked.X), this.Location.Y + (e.Y - locationClicked.Y));
}
}
private void Form1_MouseUp(object sender, MouseEventArgs e)
{
dragForm = false;
}
}