C# 绘制时替换旧值

我正在使用Windows窗体应用程序，使用一个按钮生成随机数并在窗体上绘图。当点击按钮时，它会使用图形绘制方法添加一个随机数。问题是当我第一次按下按钮时，它工作正常，并添加一个随机数，即11111。当我再次按下按钮时，它会添加一个新的随机数（在下一个位置），但它也会将以前的数字更改为新生成的随机数

更新：（添加完整代码）

编辑：我已将随机数移到独家新闻之外，因此现在它不会生成相同的数字，但仍会将旧随机数更改为其他随机数

主要类别：

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

namespace DrawingText
{
    public partial class Form1 : Form
    {

        private Point mouseDownPosition = new Point(0, 0);
        private Point mouseMovePosition = new Point(0, 0);
        private int mousePressdDown;
        private ArrayList drawnItemsList;
        Random rnd;

        public Form1()
        {
            InitializeComponent();
            drawnItemsList = new ArrayList();
            this.rnd = new Random();

        }

        private void Form1_MouseDown(object sender, MouseEventArgs e)
        {
            mouseMovePosition = e.Location;
            if (e.Button == MouseButtons.Left)
                mousePressdDown = 1;

        }

        private void Form1_MouseMove(object sender, MouseEventArgs e)
        {
            if (e.Button == MouseButtons.Left)
                mouseDownPosition = e.Location;
        }

        private void Form1_MouseUp(object sender, MouseEventArgs e)
        {
            if (mousePressdDown == 1)
            {
                label1.Text = "X: " + mouseMovePosition.X.ToString();
                label2.Text = "Y: " + mouseMovePosition.Y.ToString();
                this.Invalidate();
            }
            DrawingData a = new DrawingData(mouseMovePosition, mouseDownPosition);
            drawnItemsList.Add(a);
            mousePressdDown = 0;

        }

        private void Form1_Paint(object sender, PaintEventArgs e)
        {
            foreach (DrawingData a in drawnItemsList)
            {
                draw(e.Graphics, a.old, a.cur);

            }
         draw(e.Graphics, mouseDownPosition, mouseMovePosition);


        }
        private void draw(Graphics e, Point mold, Point mcur)
        {
            Pen p = new Pen(Color.Black, 2);

                    using (Font useFont = new Font("Gotham Medium", 28, FontStyle.Bold))
                    {
                            string header2 = rnd.Next().ToString();
                            RectangleF header2Rect = new RectangleF();
                            int moldX = mold.X - 5;
                            int moldY = mold.Y;

                            header2Rect.Location = new Point(moldX, moldY);
                            header2Rect.Size = new Size(600, ((int)e.MeasureString(header2, useFont, 600, StringFormat.GenericTypographic).Height));
                            e.DrawString(header2, useFont, Brushes.Black, header2Rect);
                        }
        }

        private void button1_Click(object sender, EventArgs e)
        {

        }
    }
}

namespace DrawingText
{
    public partial class Form1 : Form
    {
        private Point mouseDownPosition = new Point(0, 0);
        private Point mouseMovePosition = new Point(0, 0);
        private int mousePressdDown;
        private ArrayList drawnItemsList;
        Random rnd;

        public Form1()
        {
            InitializeComponent();
            drawnItemsList = new ArrayList();
            this.rnd = new Random();
        }

        private void Form1_MouseUp(object sender, MouseEventArgs e)
        {
            if (mousePressdDown == 1)
            {
                label1.Text = "X: " + mouseMovePosition.X.ToString();
                label2.Text = "Y: " + mouseMovePosition.Y.ToString();
                this.Invalidate();
            }
            DrawingData a = new DrawingData(mouseMovePosition, mouseDownPosition, rnd.Next().ToString());
            drawnItemsList.Add(a);
            mousePressdDown = 0;
        }

        private void Form1_Paint(object sender, PaintEventArgs e)
        {
            foreach (DrawingData a in drawnItemsList)
            {
                draw(e.Graphics, a);
            }
            draw(e.Graphics, mouseDownPosition, mouseMovePosition);
        }

        private void draw(Graphics e, DrawingData a)
        {
            Pen p = new Pen(Color.Black, 2);

            using (Font useFont = new Font("Gotham Medium", 28, FontStyle.Bold))
            {
                RectangleF header2Rect = new RectangleF();
                int moldX = a.old.X - 5;
                int moldY = a.old.Y;

                header2Rect.Location = new Point(moldX, moldY);
                header2Rect.Size = new Size(600, ((int)e.MeasureString(header2, useFont, 600, StringFormat.GenericTypographic).Height));
                e.DrawString(a.Rand, useFont, Brushes.Black, header2Rect);
            }
        }
    }
}

图形数据类：

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

namespace DrawingText
{
    [Serializable]
    class DrawingData
    {
        private Point mold; // mouseDown position
        private Point mcur; // mouseUp poslition

        public DrawingData()
        {
            mold = new Point(0, 0);
            mcur = new Point(0, 0);
        }
        public DrawingData(Point old, Point cur)
        {
            mold = old;
            mcur = cur;
        }

        public Point old
        {
            get
            {
                return mold;
            }
            set
            {
                mold = value;
            }
        }

        public Point cur
        {
            get
            {
                return mcur;
            }
            set
            {
                mcur = value;
            }
        }


    }
}

namespace DrawingText
{
    [Serializable]
    public class DrawingData
    {
        private Point mold; // mouseDown position
        private Point mcur; // mouseUp poslition
        private string randValue; // random data value

        public DrawingData()
        {
            mold = new Point(0, 0);
            mcur = new Point(0, 0);
            randValue = String.Empty;
        }

        public DrawingData(Point old, Point cur, string rand)
        {
            mold = old;
            mcur = cur;
            randValue = rand;
        }

        public Point old
        {
            get
            {
                return mold;
            }
            set
            {
                mold = value;
            }
        }

        public Point cur
        {
            get
            {
                return mcur;
            }
            set
            {
                mcur = value;
            }
        }

        public sting Rand
        {
            get
            {
                return randValue;
            }
            set
            {
                randValue = value;
            }
     }
}

点击按钮3次，将旧值替换为新值：

---

您每次在循环中都在重新创建随机数，这将使它具有相同的种子和相同的第一个数字。这就是为什么你所有的数字都是一样的。你应该

将随机变量移到方法和循环之外，并改用它。将行Random rnd=new Random（）更改为rnd=new Random（）。类中已经有一个变量来保存随机变量

如果您希望以前的随机数与上次保持相同，则需要将它们存储在某个位置的列表中，并在绘图上绘制它们。您当前每次都在创建一组新的随机数

---

您每次在循环中都在重新创建随机数，这将使它具有相同的种子和相同的第一个数字。这就是为什么你所有的数字都是一样的。你应该

将随机变量移到方法和循环之外，并改用它。将行Random rnd=new Random（）更改为rnd=new Random（）。类中已经有一个变量来保存随机变量

如果您希望以前的随机数与上次保持相同，则需要将它们存储在某个位置的列表中，并在绘图上绘制它们。您当前每次都在创建一组新的随机数

---

这是使用图形路径动态创建的：

    GraphicsPath gp;
    int moldX = 10;
    int moldY = 10;

    public Form1()
    {
        InitializeComponent();
        gp = new GraphicsPath();  
    }


    private void Form1_Paint(object sender, PaintEventArgs e)
    {
        e.Graphics.SmoothingMode = SmoothingMode.AntiAlias;
        e.Graphics.FillPath(Brushes.Black, gp);
        // if you want the numbers outlined do e.Graphics.DrawPath
    }

    private void button1_Click(object sender, EventArgs e)
    {
        AddToPath();
        Invalidate();   
    }

    private void AddToPath()
    {
        using (Font useFont = new Font("Gotham Medium", 28, FontStyle.Bold))
        {
            Random rnd = new Random();
            string header2 = rnd.Next().ToString();
            int strsize = TextRenderer.MeasureText(header2, useFont).Height;
            StringFormat format = StringFormat.GenericDefault;
            gp.AddString(header2, useFont.FontFamily, 1, 28, new Point(moldX, moldY), format);

            moldX += 5;
            moldY += strsize;
        }
    }

---

这是使用图形路径动态创建的：

    GraphicsPath gp;
    int moldX = 10;
    int moldY = 10;

    public Form1()
    {
        InitializeComponent();
        gp = new GraphicsPath();  
    }


    private void Form1_Paint(object sender, PaintEventArgs e)
    {
        e.Graphics.SmoothingMode = SmoothingMode.AntiAlias;
        e.Graphics.FillPath(Brushes.Black, gp);
        // if you want the numbers outlined do e.Graphics.DrawPath
    }

    private void button1_Click(object sender, EventArgs e)
    {
        AddToPath();
        Invalidate();   
    }

    private void AddToPath()
    {
        using (Font useFont = new Font("Gotham Medium", 28, FontStyle.Bold))
        {
            Random rnd = new Random();
            string header2 = rnd.Next().ToString();
            int strsize = TextRenderer.MeasureText(header2, useFont).Height;
            StringFormat format = StringFormat.GenericDefault;
            gp.AddString(header2, useFont.FontFamily, 1, 28, new Point(moldX, moldY), format);

            moldX += 5;
            moldY += strsize;
        }
    }

---

您需要将随机值与点值一起存储在

DrawingData

类中，如下所示：

主要类别：

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

namespace DrawingText
{
    public partial class Form1 : Form
    {

        private Point mouseDownPosition = new Point(0, 0);
        private Point mouseMovePosition = new Point(0, 0);
        private int mousePressdDown;
        private ArrayList drawnItemsList;
        Random rnd;

        public Form1()
        {
            InitializeComponent();
            drawnItemsList = new ArrayList();
            this.rnd = new Random();

        }

        private void Form1_MouseDown(object sender, MouseEventArgs e)
        {
            mouseMovePosition = e.Location;
            if (e.Button == MouseButtons.Left)
                mousePressdDown = 1;

        }

        private void Form1_MouseMove(object sender, MouseEventArgs e)
        {
            if (e.Button == MouseButtons.Left)
                mouseDownPosition = e.Location;
        }

        private void Form1_MouseUp(object sender, MouseEventArgs e)
        {
            if (mousePressdDown == 1)
            {
                label1.Text = "X: " + mouseMovePosition.X.ToString();
                label2.Text = "Y: " + mouseMovePosition.Y.ToString();
                this.Invalidate();
            }
            DrawingData a = new DrawingData(mouseMovePosition, mouseDownPosition);
            drawnItemsList.Add(a);
            mousePressdDown = 0;

        }

        private void Form1_Paint(object sender, PaintEventArgs e)
        {
            foreach (DrawingData a in drawnItemsList)
            {
                draw(e.Graphics, a.old, a.cur);

            }
         draw(e.Graphics, mouseDownPosition, mouseMovePosition);


        }
        private void draw(Graphics e, Point mold, Point mcur)
        {
            Pen p = new Pen(Color.Black, 2);

                    using (Font useFont = new Font("Gotham Medium", 28, FontStyle.Bold))
                    {
                            string header2 = rnd.Next().ToString();
                            RectangleF header2Rect = new RectangleF();
                            int moldX = mold.X - 5;
                            int moldY = mold.Y;

                            header2Rect.Location = new Point(moldX, moldY);
                            header2Rect.Size = new Size(600, ((int)e.MeasureString(header2, useFont, 600, StringFormat.GenericTypographic).Height));
                            e.DrawString(header2, useFont, Brushes.Black, header2Rect);
                        }
        }

        private void button1_Click(object sender, EventArgs e)
        {

        }
    }
}

namespace DrawingText
{
    public partial class Form1 : Form
    {
        private Point mouseDownPosition = new Point(0, 0);
        private Point mouseMovePosition = new Point(0, 0);
        private int mousePressdDown;
        private ArrayList drawnItemsList;
        Random rnd;

        public Form1()
        {
            InitializeComponent();
            drawnItemsList = new ArrayList();
            this.rnd = new Random();
        }

        private void Form1_MouseUp(object sender, MouseEventArgs e)
        {
            if (mousePressdDown == 1)
            {
                label1.Text = "X: " + mouseMovePosition.X.ToString();
                label2.Text = "Y: " + mouseMovePosition.Y.ToString();
                this.Invalidate();
            }
            DrawingData a = new DrawingData(mouseMovePosition, mouseDownPosition, rnd.Next().ToString());
            drawnItemsList.Add(a);
            mousePressdDown = 0;
        }

        private void Form1_Paint(object sender, PaintEventArgs e)
        {
            foreach (DrawingData a in drawnItemsList)
            {
                draw(e.Graphics, a);
            }
            draw(e.Graphics, mouseDownPosition, mouseMovePosition);
        }

        private void draw(Graphics e, DrawingData a)
        {
            Pen p = new Pen(Color.Black, 2);

            using (Font useFont = new Font("Gotham Medium", 28, FontStyle.Bold))
            {
                RectangleF header2Rect = new RectangleF();
                int moldX = a.old.X - 5;
                int moldY = a.old.Y;

                header2Rect.Location = new Point(moldX, moldY);
                header2Rect.Size = new Size(600, ((int)e.MeasureString(header2, useFont, 600, StringFormat.GenericTypographic).Height));
                e.DrawString(a.Rand, useFont, Brushes.Black, header2Rect);
            }
        }
    }
}

图形数据类：

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

namespace DrawingText
{
    [Serializable]
    class DrawingData
    {
        private Point mold; // mouseDown position
        private Point mcur; // mouseUp poslition

        public DrawingData()
        {
            mold = new Point(0, 0);
            mcur = new Point(0, 0);
        }
        public DrawingData(Point old, Point cur)
        {
            mold = old;
            mcur = cur;
        }

        public Point old
        {
            get
            {
                return mold;
            }
            set
            {
                mold = value;
            }
        }

        public Point cur
        {
            get
            {
                return mcur;
            }
            set
            {
                mcur = value;
            }
        }


    }
}

namespace DrawingText
{
    [Serializable]
    public class DrawingData
    {
        private Point mold; // mouseDown position
        private Point mcur; // mouseUp poslition
        private string randValue; // random data value

        public DrawingData()
        {
            mold = new Point(0, 0);
            mcur = new Point(0, 0);
            randValue = String.Empty;
        }

        public DrawingData(Point old, Point cur, string rand)
        {
            mold = old;
            mcur = cur;
            randValue = rand;
        }

        public Point old
        {
            get
            {
                return mold;
            }
            set
            {
                mold = value;
            }
        }

        public Point cur
        {
            get
            {
                return mcur;
            }
            set
            {
                mcur = value;
            }
        }

        public sting Rand
        {
            get
            {
                return randValue;
            }
            set
            {
                randValue = value;
            }
     }
}

---

您需要将随机值与点值一起存储在

DrawingData

类中，如下所示：

主要类别：

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

namespace DrawingText
{
    public partial class Form1 : Form
    {

        private Point mouseDownPosition = new Point(0, 0);
        private Point mouseMovePosition = new Point(0, 0);
        private int mousePressdDown;
        private ArrayList drawnItemsList;
        Random rnd;

        public Form1()
        {
            InitializeComponent();
            drawnItemsList = new ArrayList();
            this.rnd = new Random();

        }

        private void Form1_MouseDown(object sender, MouseEventArgs e)
        {
            mouseMovePosition = e.Location;
            if (e.Button == MouseButtons.Left)
                mousePressdDown = 1;

        }

        private void Form1_MouseMove(object sender, MouseEventArgs e)
        {
            if (e.Button == MouseButtons.Left)
                mouseDownPosition = e.Location;
        }

        private void Form1_MouseUp(object sender, MouseEventArgs e)
        {
            if (mousePressdDown == 1)
            {
                label1.Text = "X: " + mouseMovePosition.X.ToString();
                label2.Text = "Y: " + mouseMovePosition.Y.ToString();
                this.Invalidate();
            }
            DrawingData a = new DrawingData(mouseMovePosition, mouseDownPosition);
            drawnItemsList.Add(a);
            mousePressdDown = 0;

        }

        private void Form1_Paint(object sender, PaintEventArgs e)
        {
            foreach (DrawingData a in drawnItemsList)
            {
                draw(e.Graphics, a.old, a.cur);

            }
         draw(e.Graphics, mouseDownPosition, mouseMovePosition);


        }
        private void draw(Graphics e, Point mold, Point mcur)
        {
            Pen p = new Pen(Color.Black, 2);

                    using (Font useFont = new Font("Gotham Medium", 28, FontStyle.Bold))
                    {
                            string header2 = rnd.Next().ToString();
                            RectangleF header2Rect = new RectangleF();
                            int moldX = mold.X - 5;
                            int moldY = mold.Y;

                            header2Rect.Location = new Point(moldX, moldY);
                            header2Rect.Size = new Size(600, ((int)e.MeasureString(header2, useFont, 600, StringFormat.GenericTypographic).Height));
                            e.DrawString(header2, useFont, Brushes.Black, header2Rect);
                        }
        }

        private void button1_Click(object sender, EventArgs e)
        {

        }
    }
}

namespace DrawingText
{
    public partial class Form1 : Form
    {
        private Point mouseDownPosition = new Point(0, 0);
        private Point mouseMovePosition = new Point(0, 0);
        private int mousePressdDown;
        private ArrayList drawnItemsList;
        Random rnd;

        public Form1()
        {
            InitializeComponent();
            drawnItemsList = new ArrayList();
            this.rnd = new Random();
        }

        private void Form1_MouseUp(object sender, MouseEventArgs e)
        {
            if (mousePressdDown == 1)
            {
                label1.Text = "X: " + mouseMovePosition.X.ToString();
                label2.Text = "Y: " + mouseMovePosition.Y.ToString();
                this.Invalidate();
            }
            DrawingData a = new DrawingData(mouseMovePosition, mouseDownPosition, rnd.Next().ToString());
            drawnItemsList.Add(a);
            mousePressdDown = 0;
        }

        private void Form1_Paint(object sender, PaintEventArgs e)
        {
            foreach (DrawingData a in drawnItemsList)
            {
                draw(e.Graphics, a);
            }
            draw(e.Graphics, mouseDownPosition, mouseMovePosition);
        }

        private void draw(Graphics e, DrawingData a)
        {
            Pen p = new Pen(Color.Black, 2);

            using (Font useFont = new Font("Gotham Medium", 28, FontStyle.Bold))
            {
                RectangleF header2Rect = new RectangleF();
                int moldX = a.old.X - 5;
                int moldY = a.old.Y;

                header2Rect.Location = new Point(moldX, moldY);
                header2Rect.Size = new Size(600, ((int)e.MeasureString(header2, useFont, 600, StringFormat.GenericTypographic).Height));
                e.DrawString(a.Rand, useFont, Brushes.Black, header2Rect);
            }
        }
    }
}

图形数据类：

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

namespace DrawingText
{
    [Serializable]
    class DrawingData
    {
        private Point mold; // mouseDown position
        private Point mcur; // mouseUp poslition

        public DrawingData()
        {
            mold = new Point(0, 0);
            mcur = new Point(0, 0);
        }
        public DrawingData(Point old, Point cur)
        {
            mold = old;
            mcur = cur;
        }

        public Point old
        {
            get
            {
                return mold;
            }
            set
            {
                mold = value;
            }
        }

        public Point cur
        {
            get
            {
                return mcur;
            }
            set
            {
                mcur = value;
            }
        }


    }
}

namespace DrawingText
{
    [Serializable]
    public class DrawingData
    {
        private Point mold; // mouseDown position
        private Point mcur; // mouseUp poslition
        private string randValue; // random data value

        public DrawingData()
        {
            mold = new Point(0, 0);
            mcur = new Point(0, 0);
            randValue = String.Empty;
        }

        public DrawingData(Point old, Point cur, string rand)
        {
            mold = old;
            mcur = cur;
            randValue = rand;
        }

        public Point old
        {
            get
            {
                return mold;
            }
            set
            {
                mold = value;
            }
        }

        public Point cur
        {
            get
            {
                return mcur;
            }
            set
            {
                mcur = value;
            }
        }

        public sting Rand
        {
            get
            {
                return randValue;
            }
            set
            {
                randValue = value;
            }
     }
}

---

发布此方法的其余代码。我还建议使用相同的

Random

对象生成随机数，因此移动行

Random rnd=new Random（）

在click处理程序之外，并使对象

rnd

成为类范围。感谢大家的关注。有很长的代码，所以我刚刚创建了一个新的项目，上面的代码你们可以看到，现在我用鼠标点击表单创建随机数。但它仍然是同一个问题。代码更新：我已将Random移出了scoop，因此现在它不会生成相同的数字，但仍然会将旧的随机数更改为其他数字。发布此方法的其余代码。我还建议使用相同的Random对象生成随机数，因此，移动行

Random rnd=new Random（）

在click处理程序之外，并使对象

rnd

成为类范围。感谢大家的关注。有很长的代码，所以我刚刚创建了一个新的项目，上面的代码你们可以看到，现在我用鼠标点击表单创建随机数。但它仍然是同一个问题。代码更新：我已经将随机数移到了独家新闻之外，所以现在它不会生成相同的数字，但仍然会将旧的随机数更改为其他数字。谢谢，将随机数移到独家新闻之外产生了差异，但这次数字不一样，但每次单击其他值时，它们都会更改。我有一个列表drawnItemsList，它存储了上面的绘画元素。谢谢你，将随机移动到勺子外会产生差异，但这次数字不一样，但每次单击都会更改为其他值。我有一个列表drawnItemsList，它存储了上面的绘画元素。谢谢你的努力，亲爱的，但是从绘画到图形的转换目前还不是一个选项，因为我在绘画课上还有很多其他的东西。上面的代码我只是从大量代码中提取逻辑。亲爱的，谢谢你的努力，但是从绘图到图形的转换目前还不是一个选项，因为我在绘图类中还有很多其他的东西。上面的代码是我从大量代码中提取出来的，以获得逻辑。先生，你太棒了：），在阅读完所有内容后，我假设我还需要2个重载的方法，即Form1中的Draw，所以我添加了，所有这些都正常工作。非常感谢…事实上我正在自学Csharp（来自PHP），我现在非常喜欢c#，每天都会有新的东西出现，像你这样的了不起的家伙来帮助我…如果我可以再问一个问题，在上面的示例中，我应该在绘制的文本上单击/选择什么逻辑/代码，并在表单中的任何位置拖动/移动？再次感谢你，你真是太棒了：），读完所有内容后，我想我还需要在Form1中使用2个重载的绘图方法，所以我添加了，而且一切都正常。非常感谢…事实上我正在自学Csharp（来自PHP），我现在非常喜欢c#，每天都会有新的东西出现，像你这样的了不起的家伙来帮助我…如果我可以再问一个问题，在上面的示例中，我应该在绘制的文本上单击/选择什么逻辑/代码，并在表单中的任何位置拖动/移动？再次感谢