Question

Hello stackoverflow社区。我已经尝试过寻找类似的问题，但我只发现了有关闪烁的问题，这与我遇到的问题不一样。

每当我在面板上移动PictureBox时，我都需要帮助阻止PictureBox es跟踪。我正在制作的应用程序类似于MS Paint。当我点击private void pictureBox1_MouseDown(object sender, MouseEventArgs e) { x = e.X; y = e.Y; } private void pictureBox1_MouseMove(object sender, MouseEventArgs e) { if (e.Button == MouseButtons.Left) { pictureBox1.Left += (e.X - x); pictureBox1.Top += (e.Y - y); } }时，我可以点击并拖动它：

private void panel1_Paint(object sender, PaintEventArgs e)
{
    foreach (PictureBox pb in pboxes)
    {
        if (!pb.Visible)
        {
            e.Graphics.DrawImage(pb.BackgroundImage, new Rectangle(pb.Location, pb.Size));
        }
    }
}

和我没有点击的其他图片框被绘制到DoubleBuffered面板，使用：

PictureBox

出于某种原因，当我拖动PictureBox它的背景时，图像会拖动到绘制的面板上。

奇怪的是，这只发生在Paint事件上。如果我要将面板的背景图像设为某种东西，那么移动Image将不会跟踪。只有当我在面板上绘制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; using System.Collections; namespace WindowsFormsApplication1 { public partial class Form1 : Form { int x; int y; public Form1() { InitializeComponent(); pictureBox1.Show(); pictureBox2.Hide(); pictureBox3.Hide(); } private void pictureBox1_MouseDown(object sender, MouseEventArgs e) { x = e.X; y = e.Y; panel1.Invalidate(); } private void pictureBox1_MouseMove(object sender, MouseEventArgs e) { if (e.Button == MouseButtons.Left) { pictureBox1.Left += (e.X - x); pictureBox1.Top += (e.Y - y); } } private void panel1_Paint(object sender, PaintEventArgs e) { e.Graphics.DrawImage(pictureBox2.BackgroundImage, new Rectangle(pictureBox2.Location, pictureBox2.Size)); e.Graphics.DrawImage(pictureBox3.BackgroundImage, new Rectangle(pictureBox3.Location, pictureBox3.Size)); } }}时才会发生这种情况。

以下是 enter image description here

的示例

非常感谢任何帮助，谢谢。

我简化了代码，因此更容易理解。（尾随效果仍然存在）

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows.Forms;

namespace WindowsFormsApplication1
{
    public class DoubleBufferPanel : Panel
    {


        public DoubleBufferPanel()
        {

            // Set the value of the double-buffering style bits to true.
            this.DoubleBuffered = true;



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

            this.UpdateStyles();

        }


    }

}

它使用这个doubleBuffered面板类

PictureBox

现在，我的代码需要3 DoubleBuffered和1 Panel1.size = (2000, 1200);小组。

表单已最大化，PictureBox和每个size = (700, 700) PictureBox并将每个pictureBox1背景图片设置为随机的大型详细图片。当我移动{{1}}并且每次都可以重现这个时，会发生尾随效果。

Answer 1

您是否尝试过从OnPaint处理程序调用基础的OnPaint，或者从MouseMove中选择性地执行Invalidate / Refresh？

Answer 2

我知道这是几年前的事，但今天我遇到了类似的麻烦。我点击并拖动PictureBox来放大图像部分。通过获得正确的操作顺序来解决问题：大小，移动，绘画。我通过以下方式解决了这个问题：

在表单PictureBox事件

Load

在PictureBox活动期间重新定位Location及其MouseMove媒体资源
重定位后PictureBox无效
在通过Paint

Invalidate()

我为Region设置了自定义形状（PictureBox），该形状是在VisibleChange活动期间设置的。*
如果按下鼠标左键，PictureBox仅可见（Visible == true），且图片足够大。*

* =可选

以下是我的代码的修改摘录。我希望它们具有足够的相关性。

public Form1()
{
    InitializeComponent();

    this.Paint += new System.Windows.Forms.PaintEventHandler(Form1_Paint);
    Main_PictureBox.Paint += new PaintEventHandler(Main_PictureBox_Paint);
    Main_PictureBox.MouseDown += new MouseEventHandler(StartZoom);
    Zoom_PictureBox.MouseDown += new MouseEventHandler(StartZoom);
    Main_PictureBox.MouseMove += new MouseEventHandler(MoveZoom);
    Main_PictureBox.MouseUp += new MouseEventHandler(EndZoom);
    Main_PictureBox.MouseLeave += new EventHandler(EndZoom);
    Zoom_PictureBox.MouseUp += new MouseEventHandler(EndZoom);
    Zoom_PictureBox.VisibleChanged += new EventHandler(Zoom_PictureBox_VisibleRegion);
    Zoom_PictureBox.Paint += new PaintEventHandler(Zoom_PictureBox_Paint);
}
private void Form1_Paint(object sender, PaintEventArgs e)
{
    int H = flowLayoutPanel1.Height - flowLayoutPanel1.Margin.Size.Height;
    Main_PictureBox.MinimumSize = new Size(0, 0);
    Main_PictureBox.MaximumSize = new Size(flowLayoutPanel1.Width, H);
}
private void Main_PictureBox_Paint(object sender, PaintEventArgs e)
{
    Main_PictureBox.Parent.MaximumSize = Main_PictureBox.Size + Main_PictureBox.Margin.Size;
}
private void DisplayImage(object sender, EventArgs e)
{
    Image img = ((PictureBox)sender).Image;

    int W = img.Width;
    int H = img.Height;
    float ratio = (float)W / (float)H;

    Main_PictureBox.Image = img;
    Main_PictureBox.Size = new Size(W, H);
    float TestRatio = ((float)Main_PictureBox.Width / (float)Main_PictureBox.Height);
    if (TestRatio < ratio)
        Main_PictureBox.Height = (int)((float)Main_PictureBox.Width / ratio);
    else if (TestRatio > ratio)
        Main_PictureBox.Width = (int)((float)Main_PictureBox.Height * ratio);
}
private void Zoom_PictureBox_VisibleRegion(object sender, EventArgs e)
{
    using (var gp = new System.Drawing.Drawing2D.GraphicsPath())
    {
        gp.AddEllipse(new Rectangle(0, 0, this.Zoom_PictureBox.Width, this.Zoom_PictureBox.Height));
        this.Zoom_PictureBox.Region = new Region(gp);
    }
}
private void Zoom_PictureBox_Paint(object sender, PaintEventArgs e)
{
    e.Graphics.DrawImage(Main_PictureBox.Image, e.ClipRectangle, cropRectangle, GraphicsUnit.Pixel);
}
private void StartZoom(object sender, MouseEventArgs e)
{
    if (e.Button == MouseButtons.Left && scale > 1.25)
    {
        int dX = Zoom_PictureBox.Width / 2;
        int dY = Zoom_PictureBox.Height / 2;
        Zoom_PictureBox.Visible = true;
        Zoom_PictureBox.Location = new Point(e.X - dX, e.Y - dY);
    }
}
private void MoveZoom(object sender, MouseEventArgs e)
{
    if (Main_PictureBox.Image != null)
    {
        Zoom_PictureBox.Visible = (e.Button == MouseButtons.Left && scale > 1.25);
        if (Zoom_PictureBox.Visible && e.Button == MouseButtons.Left)
        {
            int dX = Zoom_PictureBox.Width / 2;
            int dY = Zoom_PictureBox.Height / 2;

            Zoom_PictureBox.Location = new Point(e.X - dX, e.Y - dY);
            Zoom_PictureBox.Invalidate();
        }
    }
}
private void EndZoom(object sender, MouseEventArgs e)
{
    if (e.Button == MouseButtons.Left)
        EndZoom();
}
private void EndZoom(object sender, EventArgs e)
{
    EndZoom();
}
private void EndZoom()
{
    Zoom_PictureBox.Visible = false;
}
private Rectangle cropRectangle
{
    get
    {
        if (Main_PictureBox.Image != null)
        {
            Point origin = Main_PictureBox.PointToScreen(new Point(0, 0));
            float X = (float)(MousePosition.X - origin.X);
            return new Rectangle(
                (int)(scale * X) - Zoom_PictureBox.Width / 2,
                (int)(scale * (float)(MousePosition.Y - origin.Y)) - Zoom_PictureBox.Height / 2,
                Zoom_PictureBox.Width,
                Zoom_PictureBox.Height);
        }
        else
            return new Rectangle();
    }
}
private float scale
{
    get
    {
        if (Main_PictureBox.Image != null)
            return (float)Main_PictureBox.Image.Height / (float)Main_PictureBox.Height;
        else
            return 0;
    }
}

当我移动它时，如何防止pictureBox图像拖尾？

2 个答案: