WinForms › Scroll Bars › IScrollBarThumbRenderer

IScrollBarThumbRenderer

interface.NET 6 / 8 / 10.NET Framework 4.8Binarymission.WinForms.Controls.ScrollBars

Draws a scroll bar's thumb. Implement it and assign it to ScrollBarBase.ScrollBarThumbRenderer to replace the built-in thumb; its size and position still come from the bar.

public interface IScrollBarThumbRenderer

Examples

sealed class PillThumbRenderer : IScrollBarThumbRenderer
{
    public void Draw(Graphics g, Rectangle bounds, ControlVisualState state)
    {
        var colour = state == ControlVisualState.Normal ? Color.Silver : Color.Gray;
        using (var brush = new SolidBrush(colour))
        {
            g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.AntiAlias;
            g.FillRectangle(brush, Rectangle.Inflate(bounds, -3, -3));
        }
    }
}

messagesBar.ScrollBarThumbRenderer = new PillThumbRenderer();

Members at a glance

Methods
`Draw`	Draws the thumb into its bounds.

Methods

Draw

void Draw(Graphics graphicsInstanceToDrawOnto, Rectangle drawingBounds, ControlVisualState controlVisualState)

Draws the thumb into its bounds.

Parameters

graphicsInstanceToDrawOnto: The bar's drawing surface.
drawingBounds: The thumb's bounds in the bar's client coordinates.
controlVisualState: Whether the thumb is idle, under the pointer or being dragged.