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Posted 29 Sep 2003

Simple Runtime Control Sizing and Dragging Class

, 29 Sep 2003
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Sample and brief description of simple class that enables sizing and dragging of controls on a form

Figure - Form showing selected Label control, following selection


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:

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

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.

//(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++) {
    //Position sizing handles around Control
    //Display sizing handles
    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.


  • This is the initial submission of the sample.


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


About the Author

Jim Korovessis
Program Manager General Dynamics Mission Systems Canada
Canada Canada
Manager, Customer Training in Ottawa, ON, Canada

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Comments and Discussions

QuestionDelete control Issue back labels stays (runtime) Pin
Omkaara27-Nov-15 3:22
memberOmkaara27-Nov-15 3:22 
QuestionDoes PicBox works for the custom Usercontrols Pin
SharmaShruthi7-Oct-13 21:10
memberSharmaShruthi7-Oct-13 21:10 
AnswerRe: Does PicBox works for the custom Usercontrols Pin
Jim Korovessis20-Oct-13 9:19
memberJim Korovessis20-Oct-13 9:19 
Generalplease upload the source project Pin
Tricube21-May-13 20:21
groupTricube21-May-13 20:21 
QuestionThanks! Pin
Member 96500768-Apr-13 10:59
memberMember 96500768-Apr-13 10:59 
QuestionConstrain Proportions Pin
Member 773856116-Jun-12 6:10
memberMember 773856116-Jun-12 6:10 
QuestionHow to create multiple selection on panel. Pin
tinku313-May-12 22:04
membertinku313-May-12 22:04 
GeneralThank Very Much Pin
sanaz13x6-Jan-12 0:37
membersanaz13x6-Jan-12 0:37 
SuggestionGreat article Pin
Sudarshan.chandan@gs.com13-Oct-11 23:34
memberSudarshan.chandan@gs.com13-Oct-11 23:34 
GeneralRe: Great article Pin
steffen_dec4-Jun-12 4:38
membersteffen_dec4-Jun-12 4:38 
QuestionGreat patent - Any license? Pin
Member 76904269-Oct-11 14:50
memberMember 76904269-Oct-11 14:50 
AnswerRe: Great patent - Any license? Pin
Jim Korovessis11-Oct-11 2:39
memberJim Korovessis11-Oct-11 2:39 
GeneralMy vote of 5 Pin
Bharat Mallapur14-Apr-11 2:01
memberBharat Mallapur14-Apr-11 2:01 
AnswerUpdated with multiple selection Pin
ecklerpa21-Apr-09 10:17
memberecklerpa21-Apr-09 10:17 
GeneralPickBox and Pictureboxes Pin
Juwi_uk4-Mar-09 6:04
memberJuwi_uk4-Mar-09 6:04 
GeneralMultiple controls drag n drop. [modified] Pin
VB 8.020-Feb-09 2:45
memberVB 8.020-Feb-09 2:45 
GeneralGreate code Pin
ammar7926-Jan-09 23:04
memberammar7926-Jan-09 23:04 
GeneralAdaptation for multiple selection (more than one selected control). [modified] Pin
Diego Osorio26-Dec-08 17:43
memberDiego Osorio26-Dec-08 17:43 
GeneralRe: Adaptation for multiple selection (more than one selected control). Pin
ammar7926-Jan-09 23:12
memberammar7926-Jan-09 23:12 
GeneralRe: Adaptation for multiple selection (more than one selected control). Pin
Diego Osorio27-Jan-09 2:23
memberDiego Osorio27-Jan-09 2:23 
GeneralDragging between containers Pin
dkalyan12-May-08 19:30
memberdkalyan12-May-08 19:30 
GeneralGreat Work BUT !!!! Pin
zooooooz10-May-08 3:11
memberzooooooz10-May-08 3:11 
GeneralResize Control @ Runtime Pin
ferozasi22-Apr-08 13:00
memberferozasi22-Apr-08 13:00 
GeneralMoving with keyboard Question Pin
blakadm14-Apr-08 0:53
memberblakadm14-Apr-08 0:53 
GeneralRe: Moving with keyboard Question Pin
jazzyvishal21-Jul-08 20:51
memberjazzyvishal21-Jul-08 20:51 

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