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Simple Runtime Control Sizing and Dragging Class

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29 Sep 2003Public Domain2 min read 226.7K   5.6K   99   65
Sample and brief description of simple class that enables sizing and dragging of controls on a form

Image 1

Figure - Form showing selected Label control, following selection

Introduction

The PickBox class provides sizing handles that allow the positioning and sizing on simple controls on a containing form. This C# sample was adapted from an earlier version of the class written in VB (version 6). The sample was prepared using Borland's C# Builder IDE and exported to a VS project.

Using the code

The PickBox class exposes a "WireControl" method that attaches events to a passed control, implementing “pickbox” behavior. Clicking on a “wired” control displays eight sizing handles around the perimeter of the control and enables sizing and dragging of the control via mouse event handlers provided by the class instance (see commented code for details). The following snippet illustrates the use of the PickBox class and this function from within the Sample Form:

C#
//(Excerpt from Winform.cs)
//
// Create an instance of the PickBox class
//
private PickBox pb = new PickBox();
public WinForm() // Sample Form's constuctor
{
    InitializeComponent();
    //
    // Provide a Click event handler for each control
    // that attaches a pick box to the control when clicked
    //
    foreach (Control c in this.Controls) {
        pb.WireControl(c);
    }
}

The "WireControl" method attaches a Click event handler to each passed control. When called the event handler then attaches the "pickbox", made up of eight Label controls that act as sizing handles, to the clicked control. In addition, mouse event handlers are attached to the control allowing for dragging of the control on its parent form.

C#
//(Excerpt from PickBox.cs)
private void SelectControl(object sender, EventArgs e) {
    if (m_control is Control) {
        m_control.Cursor = oldCursor;
        // Remove event any event handlers appended to last control
        // by this class
        m_control.MouseDown -= new MouseEventHandler(this.ctl_MouseDown);
        m_control.MouseMove -= new MouseEventHandler(this.ctl_MouseMove);
        m_control.MouseUp -= new MouseEventHandler(this.ctl_MouseUp);
        m_control.Click -= new EventHandler(this.SelectControl);
        m_control = null;
    }
    m_control = (Control)sender;
    //Add event handlers for moving the selected control around
    m_control.MouseDown += new MouseEventHandler(this.ctl_MouseDown);
    m_control.MouseMove += new MouseEventHandler(this.ctl_MouseMove);
    m_control.MouseUp += new MouseEventHandler(this.ctl_MouseUp);
    //Add sizing handles to Control's container (Form or PictureBox)
    for (int i = 0; i<8; i++) {
        m_control.Parent.Controls.Add(lbl[i]);
        lbl[i].BringToFront();
    }
    //Position sizing handles around Control
    MoveHandles();
    //Display sizing handles
    ShowHandles();
    oldCursor = m_control.Cursor;
    m_control.Cursor = Cursors.SizeAll;
}

The sizing handles are Labels that are created, initialized and stored in an array of Label controls when the instance of the PickBox class is constructed. MouseDown, MouseMove, and MouseUp events service the array of Labels during control sizing operations.

Points of Interest

The class sample works well for simple applications, but may exhibit some interaction within applications employing more complicated, time-critical event handling. In it’s current form it provides for the selection of only one control at a time.

The PickBox sample is a simpler, and probably less versatile C# example of the functionality presented in the C++ sample “A Sizing/Moving widget” by Andrew JM Hall.

History

  • This is the initial submission of the sample.

License

This article, along with any associated source code and files, is licensed under A Public Domain dedication


Written By
Program Manager General Dynamics Mission Systems Canada
Canada Canada
Manager, Customer Training in Ottawa, ON, Canada
www.gdcanada.com

Comments and Discussions

 
GeneralRe: Adaptation for multiple selection (more than one selected control). Pin
Diego Osorio27-Jan-09 1:23
Diego Osorio27-Jan-09 1:23 
GeneralDragging between containers Pin
dkalyan12-May-08 18:30
dkalyan12-May-08 18:30 
GeneralGreat Work BUT !!!! Pin
Ziad Khoury10-May-08 2:11
Ziad Khoury10-May-08 2:11 
GeneralResize Control @ Runtime Pin
ferozasi22-Apr-08 12:00
professionalferozasi22-Apr-08 12:00 
GeneralMoving with keyboard Question Pin
blakadm13-Apr-08 23:53
blakadm13-Apr-08 23:53 
GeneralRe: Moving with keyboard Question Pin
jazzyvishal21-Jul-08 19:51
jazzyvishal21-Jul-08 19:51 
Questionhow labels are selected which are created at button click event Pin
jassi4u2-Aug-07 19:43
jassi4u2-Aug-07 19:43 
GeneralNice Article!!! Pin
Irfan Kothari11-Apr-07 0:32
Irfan Kothari11-Apr-07 0:32 
Hello sir,

Thanks a lot,
i got exactly what i want.. Big Grin | :-D

Really a great article..Big Grin | :-D

Thanks,
Irfan


"Take Care Not Chances"

Questionhow about rotating ? Pin
Bishoy Demian19-Jan-07 13:25
Bishoy Demian19-Jan-07 13:25 
AnswerRe: how about rotating ? Pin
JK Rajesh30-Jan-07 18:59
JK Rajesh30-Jan-07 18:59 
AnswerRe: how about rotating ? Pin
Bishoy Demian30-Jan-07 20:14
Bishoy Demian30-Jan-07 20:14 
GeneralVS 2005 Pin
NewbieDude7-Feb-06 0:59
NewbieDude7-Feb-06 0:59 
GeneralRe: VS 2005 Pin
programmingfish18-Aug-06 5:03
programmingfish18-Aug-06 5:03 
GeneralUserControls Pin
dchurch2424-Jan-06 0:04
dchurch2424-Jan-06 0:04 
GeneralAdditional code for handling child controls Pin
Ronit H31-Oct-05 4:01
Ronit H31-Oct-05 4:01 
GeneralRe: Additional code for handling child controls Pin
heckknow2-Jan-07 15:54
heckknow2-Jan-07 15:54 
GeneralVB.NET code for us non-C# folks :) Pin
mpemberton27-Oct-05 9:03
mpemberton27-Oct-05 9:03 
GeneralSaving Layout Pin
kumagKayo22-Aug-05 17:06
kumagKayo22-Aug-05 17:06 
GeneralSuggestion Pin
Carl Mercier11-Jul-05 10:35
Carl Mercier11-Jul-05 10:35 
GeneralWorks great with my Custom Control + How to Unwire in Run Time Pin
babuntu24-Jun-05 12:15
babuntu24-Jun-05 12:15 
GeneralNot able to Work with runtime Control and resizing Pin
VB 8.018-Sep-07 20:22
VB 8.018-Sep-07 20:22 
Questionlimited to certain controls? Pin
davidhart8-May-05 18:18
davidhart8-May-05 18:18 
AnswerRe: limited to certain controls? Pin
25-Jul-05 3:55
suss25-Jul-05 3:55 
GeneralRe: limited to certain controls? Pin
Member 214369825-Jul-05 3:59
Member 214369825-Jul-05 3:59 
GeneralIncreasing productivity Pin
IFreezy19-Apr-05 0:37
IFreezy19-Apr-05 0:37 

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