CoreSuite.ControlSlider 1.0.1

ControlSlider

A non-visual Windows Forms component that makes a control draggable while keeping it inside the client area of a parent container, included in CoreSuite.

Overview

ControlSlider adds mouse-based dragging behavior to an existing Windows Forms control. The component observes the configured child control, calculates its new position while the left mouse button is pressed, and constrains movement to the client area of a configured parent control.

Because it is non-visual, ControlSlider does not draw its own interface. It can be configured through the Visual Studio component tray or directly in VB.NET code.

Key features

• Adds drag behavior to an existing Windows Forms control.
• Uses the left mouse button for interactive movement.
• Constrains the child to the parent's client area.
• Supports panels, labels, picture boxes, user controls, and other controls.
• Automatically manages the required mouse event handlers.
• Updates event subscriptions when Parent or Child changes.
• Supports configuration through the Visual Studio Designer.
• Has no dependency on other CoreSuite packages.

Requirements

• .NET 8 for Windows
• Windows Forms
• Windows

Installation

Install the package from NuGet:

dotnet add package CoreSuite.ControlSlider

Quick start

Import the control namespace:

Imports CoreSuite.Controls

Create a ControlSlider, assign the container to Parent, and assign the draggable control to Child:

Dim slider As New ControlSlider With {
    .Parent = CanvasPanel,
    .Child = MovablePanel
}

The user can now drag MovablePanel with the left mouse button. Its location is automatically constrained so the entire control remains inside CanvasPanel.

Designer usage

After installing the package and adding ControlSlider to the Visual Studio Toolbox:

1. Drag ControlSlider onto the form.
2. Select the component in the component tray.
3. Assign Parent to the container that defines the movement area.
4. Assign Child to the control that should be draggable.
5. Run the application and drag the child with the left mouse button.

The control assigned to Child should be contained by the control assigned to Parent.

Parent and child controls

Parent defines the coordinate system and movement boundaries:

ControlSlider1.Parent = CanvasPanel

Child identifies the control that receives the dragging behavior:

ControlSlider1.Child = MovablePanel

A typical relationship is:

CanvasPanel.Controls.Add(MovablePanel)
ControlSlider1.Parent = CanvasPanel
ControlSlider1.Child = MovablePanel

This ensures that the child's Location uses the same client coordinates that define the movement limits.

Movement behavior

Dragging begins when the user presses the left mouse button over Child. As the pointer moves, ControlSlider updates the child's location relative to the configured parent.

Movement is constrained on every edge:

• The left edge cannot move before the parent's left client boundary.
• The top edge cannot move before the parent's top client boundary.
• The right edge cannot move beyond the parent's client width.
• The bottom edge cannot move beyond the parent's client height.

Dragging ends when the left mouse button is released.

Example: draggable tool panel

The component can be used to create a movable panel inside a larger editing surface:

Public Class EditorForm
    Private ReadOnly toolPanelSlider As New ControlSlider()
    Public Sub New()
        InitializeComponent()
        toolPanelSlider.Parent = WorkspacePanel
        toolPanelSlider.Child = ToolPanel
    End Sub
End Class

The ToolPanel can contain buttons, labels, or other controls. Dragging any area that belongs to the configured child and receives its mouse events moves the panel while preserving the workspace boundaries.

Changing controls at runtime

The component can be reassigned when a different control must become draggable:

ControlSlider1.Child = SecondaryPanel

The required mouse handlers are updated automatically when the property changes. The previous child is no longer managed by that ControlSlider instance.

The parent can also be changed:

ControlSlider1.Parent = SecondaryCanvas

After reassignment, the new parent's client area defines the movement boundaries.

API reference

Properties

Behavior notes

• Parent should contain the control assigned to Child.
• Movement uses the parent control's client coordinates and client size.
• The entire child is kept inside the configured movement area.
• Dragging uses the left mouse button.
• The component manages its mouse event subscriptions when Child changes.
• Assigning a different parent changes the active movement boundaries.
• The component is non-visual and appears in the Visual Studio component tray.

Integration notes

• Configure both Parent and Child before the user interacts with the form.
• Ensure the child is smaller than the available parent client area.
• Use Anchor and Dock carefully on the child because layout processing may override locations assigned during dragging.
• Avoid simultaneously changing the child's Location from another workflow while it is being dragged.
• Perform runtime property changes on the Windows Forms UI thread.

Package information

License

MIT License.