如何停止闪烁C#winforms

Question

我有一个基本上像绘图应用程序的程序.但是,我的程序有一些闪烁的问题.我的代码中有以下行(它应该摆脱闪烁 - 但不是):

this.SetStyle(ControlStyles.AllPaintingInWmPaint 
| ControlStyles.UserPaint | ControlStyles.DoubleBuffer, true);

我的代码(减去形状的超类和子类如下:

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;

namespace Paint
{
    public partial class Paint : Form
    {
        private Point startPoint;
        private Point endPoint;
        private Rectangle rect = new Rectangle();
        private Int32 brushThickness = 0;
        private Boolean drawSPaint = false;
        private List<Shapes> listOfShapes = new List<Shapes>();
        private Color currentColor;
        private Color currentBoarderColor;
        private Boolean IsShapeRectangle = false;
        private Boolean IsShapeCircle = false;
        private Boolean IsShapeLine = false;

        public SPaint()
        {

            InitializeComponent();
            this.SetStyle(ControlStyles.AllPaintingInWmPaint | ControlStyles.UserPaint | ControlStyles.DoubleBuffer, true);

            currentColor = Color.Red;
            currentBoarderColor = Color.DodgerBlue;
            IsShapeRectangle = true; 
        }

        private void panelArea_Paint(object sender, PaintEventArgs e)
        {
            Graphics g = panelArea.CreateGraphics();

            if (drawSPaint == true)
            {

                Pen p = new Pen(Color.Blue);
                p.DashStyle = System.Drawing.Drawing2D.DashStyle.Dash;

                if (IsShapeRectangle == true)
                {
                    g.DrawRectangle(p, rect);
                }
                else if (IsShapeCircle == true)
                {
                    g.DrawEllipse(p, rect);
                }
                else if (IsShapeLine == true)
                {
                    g.DrawLine(p, startPoint, endPoint);
                }
            }
            foreach (Shapes shape in listOfShapes)
            {

                shape.Draw(g);

            }
        }

        private void panelArea_MouseDown(object sender, MouseEventArgs e)
        {

            startPoint.X = e.X;
            startPoint.Y = e.Y;

            drawSPaint = true;
        }

        private void panelArea_MouseMove(object sender, MouseEventArgs e)
        {


            if (e.Button == System.Windows.Forms.MouseButtons.Left)
            {

                if (e.X > startPoint.X)
                {
                    rect.X = startPoint.X;
                    rect.Width = e.X - startPoint.X;
                }
                else
                {
                    rect.X = e.X;
                    rect.Width = startPoint.X - e.X;
                }
                if (e.Y > startPoint.Y)
                {
                    rect.Y = startPoint.Y;
                    rect.Height = e.Y - startPoint.Y;
                }
                else
                {
                    rect.Y = e.Y;
                    rect.Height = startPoint.Y - e.Y;
                }


                panelArea.Invalidate();

            }

        }

        private void panelArea_MouseUp(object sender, MouseEventArgs e)
        {

            endPoint.X = e.X;
            endPoint.Y = e.Y;

            drawSPaint = false;

            if (rect.Width > 0 && rect.Height > 0)
            {
                if (IsShapeRectangle == true)
                {
                    listOfShapes.Add(new TheRectangles(rect, currentColor, currentBoarderColor, brushThickness));
                }
                else if (IsShapeCircle == true)
                {
                    listOfShapes.Add(new TheCircles(rect, currentColor, currentBoarderColor, brushThickness));
                }
                else if (IsShapeLine == true)
                {
                    listOfShapes.Add(new TheLines(startPoint, endPoint, currentColor, currentBoarderColor, brushThickness));
                }

                panelArea.Invalidate();
            }
        }


        private void rectangleToolStripMenuItem_Click(object sender, EventArgs e)
        {
            IsShapeRectangle = true;
            IsShapeCircle = false;
            IsShapeLine = false; 
        }

        private void ellipseToolStripMenuItem_Click(object sender, EventArgs e)
        {
            IsShapeRectangle = false;
            IsShapeCircle = true;
            IsShapeLine = false; 
        }

        private void lineToolStripMenuItem_Click(object sender, EventArgs e)
        {
            IsShapeCircle = false;
            IsShapeRectangle = false;
            IsShapeLine = true; 
        }

        private void ThicknessLevel0_Click(object sender, EventArgs e)
        {
            brushThickness = 0; 
        }

        private void ThicknessLevel2_Click(object sender, EventArgs e)
        {
            brushThickness = 2; 
        }

        private void ThicknessLevel4_Click(object sender, EventArgs e)
        {
            brushThickness = 4; 
        }

        private void ThicknessLevel6_Click(object sender, EventArgs e)
        {
            brushThickness = 6; 
        }

        private void ThicknessLevel8_Click(object sender, EventArgs e)
        {
            brushThickness = 8; 
        }

        private void ThicknessLevel10_Click(object sender, EventArgs e)
        {
            brushThickness = 10; 
        }

        private void ThicknessLevel12_Click(object sender, EventArgs e)
        {
            brushThickness = 12; 
        }

        private void ThicknessLevel14_Click(object sender, EventArgs e)
        {
            brushThickness = 14; 
        }

        private void FillColour_Click(object sender, EventArgs e)
        {

            ColorDialog fillColourDialog = new ColorDialog();
            fillColourDialog.ShowDialog();
            currentColor = fillColourDialog.Color;
            panelArea.Invalidate(); 
        }

        private void button1_Click(object sender, EventArgs e)
        {

            ColorDialog fillColourDialog = new ColorDialog();
            fillColourDialog.ShowDialog();
            currentBoarderColor = fillColourDialog.Color;
            panelArea.Invalidate(); 
        }


    }
}

我该如何阻止闪烁？

*更新:*当我直接在表单上绘图时,这段代码实际上很有效.但是,当我尝试在面板上绘图时,闪烁成为一个问题

Answer 1

对于"更干净的解决方案"并且为了继续使用基本面板,您可以简单地使用Reflection来实现双缓冲,方法是将此代码添加到包含要在其中绘制的面板的表单中

    typeof(Panel).InvokeMember("DoubleBuffered", 
    BindingFlags.SetProperty | BindingFlags.Instance | BindingFlags.NonPublic, 
    null, DrawingPanel, new object[] { true });

其中"DrawingPanel"是您要进行双缓冲的面板的名称.

自从问到这个问题以来,我知道已经过了很多时间,但这可能会对未来的某些人有所帮助.

Answer 2

终于解决了闪烁问题.由于我在面板而不是表单上绘图,下面的代码行无法解决闪烁问题:

this.SetStyle(
    ControlStyles.AllPaintingInWmPaint | 
    ControlStyles.UserPaint | 
    ControlStyles.DoubleBuffer, 
    true);

SetStyle必须是'YourProject.YourProject'类型(或从它派生),因此,你必须创建一个类(这样你就可以使用MyPanel,它将从SPaint.SPaint派生,因此允许你直接使用doublebuffering小组 - 而不是形式):

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using SPaint; 

namespace YourProject
{
    public class MyPanel : System.Windows.Forms.Panel
    {
        public MyPanel()
        {
            this.SetStyle(
                System.Windows.Forms.ControlStyles.UserPaint | 
                System.Windows.Forms.ControlStyles.AllPaintingInWmPaint | 
                System.Windows.Forms.ControlStyles.OptimizedDoubleBuffer, 
                true);
        }
    }
}

完成此操作后(尽管您真的不应该编辑设计器代码,除非您真正知道自己在做什么),否则您必须编辑Form.Designer.cs.在此文件中,您将找到如下所示的代码:

this.panelArea = new YourProject.MyPanel();

上述行需要更改为:

this.panelArea = new MyPanel(); 

完成这些步骤后,我的绘画程序不再闪烁.

对于其他任何有同样问题的人来说,问题终于解决了.

请享用!

Answer 3

将其复制并粘贴到您的项目中

protected override CreateParams CreateParams
{
    get
    {
        CreateParams handleParam = base.CreateParams;
        handleParam.ExStyle |= 0x02000000;   // WS_EX_COMPOSITED       
        return handleParam;
    }
}

这样就可以从表单级别向所有控件进行双缓冲,否则需要为每个控件单独启用双缓冲...您可能需要在此之后微调双缓冲区,因为覆盖双缓冲可能会产生不必要的副作用.

Answer 4

我曾经也有过一样的问题.我永远无法100%摆脱闪烁(见第2点),但我用过这个

protected override void OnPaint(PaintEventArgs e) {}

以及

this.DoubleBuffered = true;

闪烁的主要问题是确保你

1. 把它做成正确的订单!
2. 确保你的绘图功能<大约1/60秒

OnPaint每次需要重绘表单时,winforms都会调用该方法.有许多方法可以取消验证,包括在表单上移动鼠标光标有时可以调用重绘事件.

而且重要的一点是OnPaint,你是不是每次都从头开始,而是从你所在的地方开始,如果你填充背景颜色,你可能会变得闪烁.

最后你的gfx对象.在内部,OnPaint您将需要重新创建图形对象,但仅限于屏幕大小已更改.重新创建对象是非常昂贵的,它需要在重新创建之前进行处理(垃圾收集不能100%正确处理它,所以说文档).我创建了一个类变量

protected Graphics gfx = null;

然后在本地使用它OnPaint,但这是因为我需要在我班级的其他位置使用gfx对象.否则不要这样做.如果您只是在OnPaint中绘画,那么请使用e.Graphics!!

// clean up old graphics object
gfx.Dispose();

// recreate graphics object (dont use e.Graphics, because we need to use it 
// in other functions)
gfx = this.CreateGraphics();

希望这可以帮助.