how to move a control on mousemove in runtime?

Question

I have a WinForm application, I'm trying to move a pictureBox in a Form using MouseMove Event, but i can't figure out what's the right calculation should i do on MouseMove, when i first the pictureBox , its location changes in a senseless way then on moving the pictureBox Location moves correctly.

It's a Panel name OuterPanel which contains the pictureBox picBox, here the code im using :

private void picBox_MouseMove(object sender, MouseEventArgs e)
{
    if (e.Button == MouseButtons.Left)
    {
        Point p = OuterPanel.PointToClient(MousePosition);
        picBox.Location = this.PointToClient(p);
    }
}

P.S : the goal is moving image after zooming in, like windows photo viewer

Update : ConvertFromChildToForm method

private Point ConvertFromChildToForm(int x, int y,Control control)
{
    Point p = new Point(x, y);
    control.Location = p;
    return p;
}

Answer 1

You have to Manage three Events to get it done correctly :

• MouseDown
• MouseMove
• MouseUp

Here is a Related SO Question..

Your Code for picBox :

private void picBox_MouseDown(object sender, MouseEventArgs e)
{
    if (e.Button == MouseButtons.Left)
    {
        Point p = ConvertFromChildToForm(e.X, e.Y, picBox);
        iOldX = p.X;
        iOldY = p.Y;
        iClickX = e.X;
        iClickY = e.Y;
        clicked = true;
    }
}

private void picBox_MouseMove(object sender, MouseEventArgs e)
{
    if (clicked)
    {
        Point p = new Point(); // New Coordinate
        p.X =  e.X + picBox.Left;
        p.Y =  e.Y + picBox.Top;
        picBox.Left = p.X - iClickX;
        picBox.Top = p.Y - iClickY;
    }
}

private void picBox_MouseUp(object sender, MouseEventArgs e)
{
    clicked = false;   
}

private Point ConvertFromChildToForm(int x, int y, Control control)
{
    Point p = new Point(x, y);
    control.Location = p;
    return p;
}

ConvertFromChildToForm method from Mur Haf Soz

Answer 2

with use

ControlMoverOrResizer

class in this article you can do movable and resizable control in run time just with a line of code! :) example:

ControlMoverOrResizer.Init(button1);   

and now button1 is a movable and resizable control!

Answer 3

Try this. It's beautiful.

const uint WM_NCLBUTTONDOWN = 161;
const uint HTCAPTION = 2;

[DllImport("user32.dll")]
public static extern bool ReleaseCapture();
[DllImport("user32.dll")]
public static extern IntPtr SendMessage(IntPtr window, uint message, IntPtr wParam, IntPtr lParam);

public Form1()
{
    PictureBox picBox = new PictureBox();
    picBox.Text = "this control is crazy!";
    picBox.BackColor = Color.Red;
    picBox.SetBounds(8, 8, 128, 64);
    picBox.MouseDown += OnMouseDown;
    Controls.Add(picBox);
}

private void OnMouseDown(object sender, MouseEventArgs e)
{
    ReleaseCapture();
    SendMessage((sender as Control).Handle, WM_NCLBUTTONDOWN, (IntPtr) HTCAPION, IntPtr.Zero);
}

The catch is only that you have to work with WinApi. And it won't let labels move. Dunno why.