Develop Reference

How to store locations properly

I have this form that allows the user to create pictureboxes by clicking and dragging them around with mouse movement. How can I store the coordinates (locations) of where the pictureboxes are each time one is added or when one is moved to a new spot? I am trying to store them in a list as strings for exportation.
private void Form_MouseClick(object sender, MouseEventArgs e)
{
// create new control
PictureBox pictureBox = new PictureBox();
pictureBox.Location = new Point(e.X, e.Y);
pictureBox.BackColor = Color.Red;
this.Controls.Add(pictureBox);
// bind event for each PictureBox
pictureBox.MouseDown += pictureBox_MouseDown;
pictureBox.MouseUp += pictureBox_MouseUp;
pictureBox.MouseMove += pictureBox_MouseMove;
}
Point mouseDownPoint = Point.Empty;
Rectangle rect = Rectangle.Empty;
bool isDrag = false;
private void pictureBox_MouseDown(object sender, MouseEventArgs e)
{
if (e.Button == MouseButtons.Left)
{
mouseDownPoint = e.Location;
rect = (sender as PictureBox).Bounds;
}
}
private void pictureBox_MouseUp(object sender, MouseEventArgs e)
{
if (e.Button == MouseButtons.Left)
{
if (isDrag)
{
isDrag = false;
(sender as PictureBox).Location = rect.Location;
this.Refresh();
}
reset();
}
}
private void pictureBox_MouseMove(object sender, MouseEventArgs e)
{
if (e.Button == MouseButtons.Left)
{
isDrag = true;
rect.Location = this.PointToClient((sender as PictureBox).PointToScreen(new Point(e.Location.X - mouseDownPoint.X, e.Location.Y - mouseDownPoint.Y)));
this.Refresh();
}
}
private void reset()
{
mouseDownPoint = Point.Empty;
rect = Rectangle.Empty;
isDrag = false;
}

To save the loaction of each picturebox, you can define a dictionary to save the key-value pair.
First, define the dictionary box_location_Pairs as a global variable.
Then add the new item to dictionary when "click to a create new picturebox".
Dictionary<PictureBox, Point> box_location_Pairs = new Dictionary<PictureBox, Point>();
// ...
private void Form_MouseClick(object sender, MouseEventArgs e)
{
PictureBox pictureBox = new PictureBox();
pictureBox.Location = new Point(e.X, e.Y);
box_location_Pairs.Add(pictureBox, pictureBox.Location);
// ...
}
If the picturebox is moved, modify its value.
private void pictureBox_MouseUp(object sender, MouseEventArgs e)
{
if (e.Button == MouseButtons.Left)
{
if (isDrag)
{
isDrag = false;
(sender as PictureBox).Location = rect.Location;
box_location_Pairs[sender as PictureBox] = rect.Location; // modifty key-value pair
this.Refresh();
}
reset();
}
}

How to get picturebox pixel color on mousemove

I tried to make drag and drop application . I drawn rectangle in run time and I want to detect if user try to move this rectangle or not
this is my code
private bool Mouse_Down = false;
Rectangle re = new Rectangle(100, 100, 60, 60);
private void DrawRegion_Paint(object sender, PaintEventArgs e)
{
e.Graphics.FillRectangle(new SolidBrush(Color.RoyalBlue), re);
}
private void DrawRegion_MouseMove(object sender, MouseEventArgs e)
{
if (Mouse_Down == true)
{
re.Location = e.Location;
if (re.Right > DrawRegion.Width)
{
re.X = DrawRegion.Width - re.Width;
}
if (re.Top < 0)
{
re.Y = 0;
}
if (re.Left < 0)
{
re.X = 0;
}
if (re.Bottom > DrawRegion.Height)
{
re.Y = DrawRegion.Height - re.Height;
}
Refresh();
}
}
private void DrawRegion_MouseUp(object sender, MouseEventArgs e)
{
Mouse_Down = false;
}
private void DrawRegion_MouseDown(object sender, MouseEventArgs e)
{
Mouse_Down = true;
}
For more details now this rectangle move either user click on this rectangle or in any empty space so I want to detect if clicked location color pixel is rectangle color pixel or not before moving rectangle how to do that ?
Note:DrawRegion is a picturebox
Sorry for bad English

You can use Rect.Contains() to detect if your Rectaingle contain your current location
private void DrawRegion_MouseClick(object sender,MouseEventArgs e)
{
if (re.Contains(e.Location))
Mouse_Down = true;
else
Mouse_Down = false;
}
check this https://msdn.microsoft.com/en-us/library/ms557979(v=vs.110).aspx

mouse position give wrong co-ordinates within group box

When I give mouse potion to label, it appear much down and left to the current mouse position.
Label inside one group box and group box contain more then 50% of the form area.
Group Box is compulsory here.
I'm trying with this code.
int xX, yY = 0;
protected override void OnMouseMove(MouseEventArgs e) {
base.OnMouseMove(e);
xX = e.X;
yY = e.Y;
lbl.Left = xX;
lbl.Top = yY;
}

It looks like you want to move the label within the boundaries of a panel, so you should add an event handler for the MouseMove event of the panel.
public Form1()
{
InitializeComponent();
panel1.MouseMove += panel1_MouseMove;
}
void panel1_MouseMove(object sender, MouseEventArgs e)
{
lbl.Location = e.Location;
}

public frmChequeFormat()
{
InitializeComponent();
gbCheque.MouseMove += gbCheque_MouseMove;
}
bool mDown = false;
private void gbCheque_MouseMove(object sender, MouseEventArgs e)
{
if (mDown)
{
label13.Location = e.Location;
}
}
private void label13_MouseDown(object sender, MouseEventArgs e)
{
mDown = true;
}
private void label13_MouseUp(object sender, MouseEventArgs e)
{
mDown = false;
}

Draw a Circle on a C# PictureBox

Hi I'm using the code below to draw a circle on a pictureBox, The problem is I don't know why some times if I draw a circle it whon show until I draw an other, some times it will show on the first circle.
public partial class Form1 : Form
{
private bool isMoving = false;
private Point mouseDownPosition = Point.Empty;
private Point mouseMovePosition = Point.Empty;
private List<Tuple<Point, Point>> lines = new List<Tuple<Point, Point>>();
public Form1()
{
InitializeComponent();
//
// pictureBox1
//
this.pictureBox1.Location = new System.Drawing.Point(0, 0);
this.pictureBox1.Name = "pictureBox1";
this.pictureBox1.Size = new System.Drawing.Size(231, 235);
this.pictureBox1.TabIndex = 0;
this.pictureBox1.TabStop = false;
this.pictureBox1.Paint += new System.Windows.Forms.PaintEventHandler(this.pictureBox1_Paint);
this.pictureBox1.MouseDown += new System.Windows.Forms.MouseEventHandler(this.pictureBox1_MouseDown);
this.pictureBox1.MouseMove += new System.Windows.Forms.MouseEventHandler(this.pictureBox1_MouseMove);
this.pictureBox1.MouseUp += new System.Windows.Forms.MouseEventHandler(this.pictureBox1_MouseUp);
this.Controls.Add(this.pictureBox1);
}
private void pictureBox1_Paint(object sender, PaintEventArgs e)
{
var g = e.Graphics;
if (isMoving)
{
g.Clear(pictureBox1.BackColor);
g.DrawLine(Pens.Black, mouseDownPosition, mouseMovePosition);
foreach (var line in lines)
{
g.DrawLine(Pens.Black, line.Item1, line.Item2);
}
}
}
private void pictureBox1_MouseDown(object sender, MouseEventArgs e)
{
isMoving = true;
mouseDownPosition = e.Location;
}
private void pictureBox1_MouseMove(object sender, MouseEventArgs e)
{
if (isMoving)
{
mouseMovePosition = e.Location;
pictureBox1.Invalidate();
}
}
private void pictureBox1_MouseUp(object sender, MouseEventArgs e)
{
if (isMoving)
{
lines.Add(Tuple.Create(mouseDownPosition, mouseMovePosition));
}
isMoving = false;
}
}

Use Refresh() instead of using Invalidate(). This will force the re-paint event to be called. Note that you may see a performance drop if you excessively repaint the screen.
private void pictureBox1_MouseMove(object sender, MouseEventArgs e)
{
if (isMoving)
{
mouseMovePosition = e.Location;
pictureBox1.Refresh();
}
}

I don't see any circles in your sample:)
I noticed your code was behaving a bit weird, when I added the following it seemed to make it run a bit better.
this.pictureBox1.MouseClick += pictureBox1_MouseClick;
...
void pictureBox1_MouseClick(object sender, MouseEventArgs e)
{
isMoving = false;
}
Hope this helps :)

How to pan Image inside PictureBox

I have a custom PictureBox which can zoom in using MouseWheel event. Now I want to add a panning feature to it. I mean when PictureBox is in zoomed state, if user left clicks and holds the click then move the mouse, the image would pan within the picturebox.
Here is my code but unfortunately it does not work! I don't know where to look anymore...
private Point _panStartingPoint = Point.Empty;
private bool _panIsActive;
private void CurveBox_MouseDown(object sender, MouseEventArgs e)
{
if (e.Button == MouseButtons.Left)
{
Focus();
_panIsActive = true;
_panStartingPoint = e.Location;
}
}
private void CurveBox_MouseUp(object sender, MouseEventArgs e)
{
_panIsActive = false;
}
private void CurveBox_MouseLeave(object sender, EventArgs e)
{
_panIsActive = false;
}
private void CurveBox_MouseMove(object sender, MouseEventArgs e)
{
if(_panIsActive && IsZoomed)
{
var g = CreateGraphics(); //Create graphics from PictureBox
var nx = _panStartingPoint.X + e.X;
var ny = _panStartingPoint.Y + e.Y;
var sourceRectangle = new Rectangle(nx, ny, Image.Width, Image.Height);
g.DrawImage(Image, nx, ny, sourceRectangle, GraphicsUnit.Pixel);
}
}
I am suspecting the MouseMove event...I am not sure if anything happens in this event and/or nx and ny does contain correct point.
Any helps/tips is really appriciated!

I think the math is backwards. Try it like this:
private Point startingPoint = Point.Empty;
private Point movingPoint = Point.Empty;
private bool panning = false;
void pictureBox1_MouseDown(object sender, MouseEventArgs e) {
panning = true;
startingPoint = new Point(e.Location.X - movingPoint.X,
e.Location.Y - movingPoint.Y);
}
void pictureBox1_MouseUp(object sender, MouseEventArgs e) {
panning = false;
}
void pictureBox1_MouseMove(object sender, MouseEventArgs e) {
if (panning) {
movingPoint = new Point(e.Location.X - startingPoint.X,
e.Location.Y - startingPoint.Y);
pictureBox1.Invalidate();
}
}
void pictureBox1_Paint(object sender, PaintEventArgs e) {
e.Graphics.Clear(Color.White);
e.Graphics.DrawImage(Image, movingPoint);
}
You aren't disposing your graphic object, and CreateGraphics is just a temporary drawing anyway (minimizing would erase it) so I moved the drawing code to the Paint event and am just invalidating as the user is panning.