How can user resize control at runtime in winforms
Say i have a pictureBox.
Now what i want is that user should be able to resize the pictureBox at will. However i have no idea on how to even start on this thing. I have searched internet however information is scarce.
Can anybody at least guide me on where to start ?
This is pretty easy to do, every window in Windows has the innate ability to be resizable. It is just turned off for a PictureBox, you can turn it back on by listening for the WM_NCHITTEST message. You simply tell Windows that the cursor is on a corner of a window, you get everything else for free. You'll also want to draw a grab handle so it is clear to the user that dragging the corner will resize the box.
Add a new class to your project and paste the code shown below. Build + Build. You'll get a new control on top of the toolbox, drop it on a form. Set the Image property and you're set to try it.
using System;
using System.Drawing;
using System.Windows.Forms;
class SizeablePictureBox : PictureBox {
public SizeablePictureBox() {
this.ResizeRedraw = true;
}
protected override void OnPaint(PaintEventArgs e) {
base.OnPaint(e);
var rc = new Rectangle(this.ClientSize.Width - grab, this.ClientSize.Height - grab, grab, grab);
ControlPaint.DrawSizeGrip(e.Graphics, this.BackColor, rc);
}
protected override void WndProc(ref Message m) {
base.WndProc(ref m);
if (m.Msg == 0x84) { // Trap WM_NCHITTEST
var pos = this.PointToClient(new Point(m.LParam.ToInt32()));
if (pos.X >= this.ClientSize.Width - grab && pos.Y >= this.ClientSize.Height - grab)
m.Result = new IntPtr(17); // HT_BOTTOMRIGHT
}
}
private const int grab = 16;
}
Another very cheap way to get the resizing for free is by giving the control a resizable border. Which works on all corners and edges. Paste this code into the class (you don't need WndProc anymore):
protected override CreateParams CreateParams {
get {
var cp = base.CreateParams;
cp.Style |= 0x840000; // Turn on WS_BORDER + WS_THICKFRAME
return cp;
}
}
here is an article
http://www.codeproject.com/Articles/20716/Allow-the-User-to-Resize-Controls-at-Runtime
that should help you since it in vb here a C# translation
using System;
using System.Collections;
using System.Collections.Generic;
using System.Data;
using System.Diagnostics;
public class Form1
{
ResizeableControl rc;
private void Form1_Load(System.Object sender, System.EventArgs e)
{
rc = new ResizeableControl(pbDemo);
}
public Form1()
{
Load += Form1_Load;
}
}
AND RE-SIZE FUNCTION
using System;
using System.Collections;
using System.Collections.Generic;
using System.Data;
using System.Diagnostics;
public class ResizeableControl
{
private Control withEventsField_mControl;
private Control mControl {
get { return withEventsField_mControl; }
set {
if (withEventsField_mControl != null) {
withEventsField_mControl.MouseDown -= mControl_MouseDown;
withEventsField_mControl.MouseUp -= mControl_MouseUp;
withEventsField_mControl.MouseMove -= mControl_MouseMove;
withEventsField_mControl.MouseLeave -= mControl_MouseLeave;
}
withEventsField_mControl = value;
if (withEventsField_mControl != null) {
withEventsField_mControl.MouseDown += mControl_MouseDown;
withEventsField_mControl.MouseUp += mControl_MouseUp;
withEventsField_mControl.MouseMove += mControl_MouseMove;
withEventsField_mControl.MouseLeave += mControl_MouseLeave;
}
}
}
private bool mMouseDown = false;
private EdgeEnum mEdge = EdgeEnum.None;
private int mWidth = 4;
private bool mOutlineDrawn = false;
private enum EdgeEnum
{
None,
Right,
Left,
Top,
Bottom,
TopLeft
}
public ResizeableControl(Control Control)
{
mControl = Control;
}
private void mControl_MouseDown(object sender, System.Windows.Forms.MouseEventArgs e)
{
if (e.Button == System.Windows.Forms.MouseButtons.Left) {
mMouseDown = true;
}
}
private void mControl_MouseUp(object sender, System.Windows.Forms.MouseEventArgs e)
{
mMouseDown = false;
}
private void mControl_MouseMove(object sender, System.Windows.Forms.MouseEventArgs e)
{
Control c = (Control)sender;
Graphics g = c.CreateGraphics;
switch (mEdge) {
case EdgeEnum.TopLeft:
g.FillRectangle(Brushes.Fuchsia, 0, 0, mWidth * 4, mWidth * 4);
mOutlineDrawn = true;
break;
case EdgeEnum.Left:
g.FillRectangle(Brushes.Fuchsia, 0, 0, mWidth, c.Height);
mOutlineDrawn = true;
break;
case EdgeEnum.Right:
g.FillRectangle(Brushes.Fuchsia, c.Width - mWidth, 0, c.Width, c.Height);
mOutlineDrawn = true;
break;
case EdgeEnum.Top:
g.FillRectangle(Brushes.Fuchsia, 0, 0, c.Width, mWidth);
mOutlineDrawn = true;
break;
case EdgeEnum.Bottom:
g.FillRectangle(Brushes.Fuchsia, 0, c.Height - mWidth, c.Width, mWidth);
mOutlineDrawn = true;
break;
case EdgeEnum.None:
if (mOutlineDrawn) {
c.Refresh();
mOutlineDrawn = false;
}
break;
}
if (mMouseDown & mEdge != EdgeEnum.None) {
c.SuspendLayout();
switch (mEdge) {
case EdgeEnum.TopLeft:
c.SetBounds(c.Left + e.X, c.Top + e.Y, c.Width, c.Height);
break;
case EdgeEnum.Left:
c.SetBounds(c.Left + e.X, c.Top, c.Width - e.X, c.Height);
break;
case EdgeEnum.Right:
c.SetBounds(c.Left, c.Top, c.Width - (c.Width - e.X), c.Height);
break;
case EdgeEnum.Top:
c.SetBounds(c.Left, c.Top + e.Y, c.Width, c.Height - e.Y);
break;
case EdgeEnum.Bottom:
c.SetBounds(c.Left, c.Top, c.Width, c.Height - (c.Height - e.Y));
break;
}
c.ResumeLayout();
} else {
switch (true) {
case e.X <= (mWidth * 4) & e.Y <= (mWidth * 4):
//top left corner
c.Cursor = Cursors.SizeAll;
mEdge = EdgeEnum.TopLeft;
break;
case e.X <= mWidth:
//left edge
c.Cursor = Cursors.VSplit;
mEdge = EdgeEnum.Left;
break;
case e.X > c.Width - (mWidth + 1):
//right edge
c.Cursor = Cursors.VSplit;
mEdge = EdgeEnum.Right;
break;
case e.Y <= mWidth:
//top edge
c.Cursor = Cursors.HSplit;
mEdge = EdgeEnum.Top;
break;
case e.Y > c.Height - (mWidth + 1):
//bottom edge
c.Cursor = Cursors.HSplit;
mEdge = EdgeEnum.Bottom;
break;
default:
//no edge
c.Cursor = Cursors.Default;
mEdge = EdgeEnum.None;
break;
}
}
}
private void mControl_MouseLeave(object sender, System.EventArgs e)
{
Control c = (Control)sender;
mEdge = EdgeEnum.None;
c.Refresh();
}
}
with use ControlMoverOrResizer class in this article you can do movable and resizable controls in run time just with a line of code! :) example:
ControlMoverOrResizer.Init(button1);
and now button1 is a movable and resizable control!