用于改变焦点颜色和焦点丢失的CUstom按钮

Question

嗨我尝试制作一个自定义按钮，其渐变颜色在单击另一个按钮时会发生变化。这是我喜欢的代码

public class GradientButton : Button
{
    private Color _Color1 = Color.LightSteelBlue;
    private Color _Color2 = Color.White;
    private Color _Color3 = Color.Orange;
    private Color _Color4 = Color.LightSteelBlue;

    public Color TopColor
    {
        get { return _Color1; }
        set { _Color1 = value; }
    }
    public Color BottomColor
    {
        get { return _Color1; }
        set { _Color1 = value; }
    }
    public Color FocusColor
    {
        get { return _Color3; }
        set { _Color3 = value; }
    }

    protected override void OnPaint(PaintEventArgs e)
    {
        base.OnPaint(e);
        using (var brush = new LinearGradientBrush(this.ClientRectangle, _Color1, _Color2, LinearGradientMode.Vertical))
        {
            e.Graphics.FillRectangle(brush, this.ClientRectangle);
        }
    }

    protected override void OnGotFocus(EventArgs e)
    {
        base.OnGotFocus(e);
        _Color1 = _Color3;
        this.Invalidate();
    }

    protected override void OnLostFocus(EventArgs e)
    {
        base.OnLostFocus(e);
        _Color1 = _Color4;
        this.Invalidate();
    }

    public GradientButton()
    {

    }
}

进行控制，当ai在设计模式下将其放置在表格上时，渐变是LightSteelBlue到白色，正如我所料。但是，当我运行表单时，无论是否单击，该按钮都会变为橙色。我怎样才能证明这个