c# - 项目中按钮闪烁的问题

Question

一天中的好时光。这个问题非常奇怪和难以理解。成功创建按钮，然后使用它后，我注意到一个非常令人不快的错误，闪烁的按钮。即，它很容易播放，打开项目，然后按 ALT 按钮。出于某种原因，按钮闪烁一次，仅此而已。我不明白为什么会发生这种情况以及如何解决它。 请帮忙。

using System;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Windows.Forms;

namespace TestProject
{
    public class RoundButton : Control
    {
        public Color BackColor2 { get; set; }
        public Color ButtonBorderColor { get; set; }
        public int ButtonRoundRadius { get; set; }

        public Color ButtonHighlightColor { get; set; }
        public Color ButtonHighlightColor2 { get; set; }
        public Color ButtonHighlightForeColor { get; set; }

        public Color ButtonPressedColor { get; set; }
        public Color ButtonPressedColor2 { get; set; }
        public Color ButtonPressedForeColor { get; set; }

        private bool IsHighlighted;
        private bool IsPressed;

        public RoundButton()
        {
            Size = new Size(100, 40);
            ButtonRoundRadius = 30;
            BackColor = Color.Gainsboro;
            BackColor2 = Color.Silver;
            ButtonBorderColor = Color.Black;
            ButtonHighlightColor = Color.Orange;
            ButtonHighlightColor2 = Color.OrangeRed;
            ButtonHighlightForeColor = Color.Black;

            ButtonPressedColor = Color.Red;
            ButtonPressedColor2 = Color.Maroon;
            ButtonPressedForeColor = Color.White;
        }

        protected override CreateParams CreateParams
        {
            get
            {
                CreateParams createParams = base.CreateParams;
                createParams.ExStyle |= 0x00000020; // WS_EX_TRANSPARENT
                return createParams;
            }
        }

        protected override void OnPaint(PaintEventArgs e)
        {
            e.Graphics.SmoothingMode = SmoothingMode.HighQuality;

            var foreColor = IsPressed ? ButtonPressedForeColor : IsHighlighted ? ButtonHighlightForeColor : ForeColor;
            var backColor = IsPressed ? ButtonPressedColor : IsHighlighted ? ButtonHighlightColor : BackColor;
            var backColor2 = IsPressed ? ButtonPressedColor2 : IsHighlighted ? ButtonHighlightColor2 : BackColor2;


            using (var pen = new Pen(ButtonBorderColor, 1))
                e.Graphics.DrawPath(pen, Path);

            using (var brush = new LinearGradientBrush(ClientRectangle, backColor, backColor2, LinearGradientMode.Vertical))
                e.Graphics.FillPath(brush, Path);

            using (var brush = new SolidBrush(foreColor))
            {
                var sf = new StringFormat { Alignment = StringAlignment.Center, LineAlignment = StringAlignment.Center };
                var rect = ClientRectangle;
                rect.Inflate(-4, -4);
                e.Graphics.DrawString(Text, Font, brush, rect, sf);
            }

            base.OnPaint(e);
        }

        protected override void OnPaintBackground(PaintEventArgs e)
        {
        }

        protected override void OnMouseEnter(EventArgs e)
        {
            base.OnMouseEnter(e);
            IsHighlighted = true;
            Parent.Invalidate(Bounds, false);
            Invalidate();
        }

        protected override void OnMouseLeave(EventArgs e)
        {
            base.OnMouseLeave(e);
            IsHighlighted = false;
            IsPressed = false;
            Parent.Invalidate(Bounds, false);
            Invalidate();
        }

        protected override void OnMouseDown(MouseEventArgs e)
        {
            base.OnMouseDown(e);
            IsPressed = true;
            Parent.Invalidate(Bounds, false);
            Invalidate();
        }

        protected override void OnMouseUp(MouseEventArgs e)
        {
            base.OnMouseUp(e);
            Parent.Invalidate(Bounds, false);
            Invalidate();
            IsPressed = false;
        }

        protected GraphicsPath Path
        {
            get
            {
                var rect = ClientRectangle;
                rect.Inflate(-1, -1);
                return GetRoundedRectangle(rect, ButtonRoundRadius);
            }
        }

        public static GraphicsPath GetRoundedRectangle(Rectangle rect, int d)
        {
            var gp = new GraphicsPath();

            gp.AddArc(rect.X, rect.Y, d, d, 180, 90);
            gp.AddArc(rect.X + rect.Width - d, rect.Y, d, d, 270, 90);
            gp.AddArc(rect.X + rect.Width - d, rect.Y + rect.Height - d, d, d, 0, 90);
            gp.AddArc(rect.X, rect.Y + rect.Height - d, d, d, 90, 90);
            gp.CloseFigure();

            return gp;
        }
    }
}

标签： c#winforms

Answer 1

当按下 ALT 键时，OnPaint()事件被调用并且控件被重绘（如果你放了一个断点，你会看到它）。
它来自类的基Control类。
您可以通过将此方法添加到自定义控件的父窗体来解决此问题：

protected override void WndProc(ref Message msg)
{
    if (msg.Msg == 0x128) return;
    base.WndProc(ref msg);
}

我猜原因是 ALT 键用于其他功能Control，例如，从MenuStrip控件中选择菜单项。