c#悬停时在控件周围绘制矩形

Question

我重写了 Control 类的 OnPaint 方法来创建表情符号。表情符号已创建。但是我要在它悬停时在它周围添加一个矩形。

public class EmoticonControl : Control
{
    public EmoticonControl(string unicode, Image image)
    {
        this.unicode = unicode;
        this.image = image;
    }

    protected override void OnPaint(PaintEventArgs e)
    {
        Graphics graphics = e.Graphics;
        Rectangle clipRectangle = e.ClipRectangle;
        graphics.DrawImage(this.image, 0, 0, this.Size.Width, this.Size.Height);

        // When hovered
        Brush brush = new SolidBrush(this.selectedColor);
        graphics.FillRectangle(new SolidBrush(selectionColor), clipRectangle);
        graphics.DrawRectangle(new Pen(selectionBorderColor), clipRectangle.X, clipRectangle.Y, clipRectangle.Width - 1, clipRectangle.Height - 1);
        //
    }
    private string unicode;
    private Image image;

    private Color selectedColor = SystemColors.Highlight;
    private Color selectionColor = Color.FromArgb(50, 0, 0, 150);
    private Color selectionBorderColor = SystemColors.Highlight;
}

Answer 1

您可以使用 UIElement.IsMouseOver 属性来了解您的控件是否处于悬停状态。

protected override void OnPaint(PaintEventArgs e)
{
    Graphics graphics = e.Graphics;
    Rectangle clipRectangle = e.ClipRectangle;
    graphics.DrawImage(this.image, 0, 0, this.Size.Width, this.Size.Height);

    // When hovered
    if (IsMouseOver)
    {
        Brush brush = new SolidBrush(this.selectedColor);
        graphics.FillRectangle(new SolidBrush(selectionColor), clipRectangle);
        graphics.DrawRectangle(new Pen(selectionBorderColor), clipRectangle.X, clipRectangle.Y, clipRectangle.Width - 1, clipRectangle.Height - 1);
    }
}