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本文介绍: GDI+绘制的一些常用的图形，其中包括柱形图、折线图和饼形图。

目录

一、柱形图

1.示例源码

2.生成效果

二、折线图

1.示例源码

2.生成效果

三、饼形图 

1.示例源码

2.生成效果

        GDI+绘制的一些常用的图形，其中包括柱形图、折线图和饼形图。

一、柱形图

        柱形图也称为条形图，是程序开发中比较常用的一种图表技术。柱形图是通过Graphics
类中的FillRectangle()方法实现的。 
public void FillRectangle (Brush brush,int x,int y,int width,int height)
参    数 说    明
brush 确定填充特性的Brush
X 要填充矩形左上角的x坐标
y 要填充矩形左上角的y坐标
width 要填充矩形的宽度
height 要填充矩形的高度

1.示例源码

         ,NET 8.0的项目中需要使用NuGet程序包：system.data.sqlclient.4.8.5.nupkg或更高级版本。否则不能使用SqlClient的方法。

//Form1.cs
//投票窗口
using System.Data.SqlClient;

namespace _12
{
    public partial class Form1 : Form
    {
        SqlConnection? conn;

        public Form1()
        {
            InitializeComponent();
        }
        
        private void Form1_Load(object sender, EventArgs e)
        {
            ClientSize = new Size(292, 192);        //设置Form1工作区域
            StartPosition = FormStartPosition.CenterScreen;
            radioButton1.Checked = false;

            radioButton1.Text = "支付宝";
            radioButton2.Text = "微信支付";
            radioButton3.Text = "京东白条";
            radioButton4.Text = "小度钱包";
            button1.Text = "投一票吧";
            button2.Text = "投票结果";
            groupBox1.Text = "投票窗口";

            radioButton1.Location = new Point(26, 37);
            radioButton2.Location = new Point(26, 68);
            radioButton3.Location = new Point(26, 101);
            radioButton4.Location = new Point(26, 132);
            radioButton1.Size = new Size(60, 16);
            radioButton2.Size = new Size(60, 16);
            radioButton3.Size = new Size(60, 16);
            radioButton4.Size = new Size(60, 16);
            button1.Location = new Point(195, 94);
            button2.Location = new Point(195, 132);
            button1.Size = new Size(75, 23);
            button2.Size = new Size(75, 23);
        }

        private void Button1_Click(object sender, EventArgs e)
        {
            try
            {
                conn = new SqlConnection(@"server=DESKTOP-S11C97HSQLEXPRESS;database=db_CSharp;integrated security = True");
                string sqlstr = "";
                if (radioButton1.Checked)
                {
                    sqlstr = "update tb_vote set 票数=票数+1 where 选项='" + radioButton1.Text + "'";
                }
                if (radioButton2.Checked)
                {
                    sqlstr = "update tb_vote set 票数=票数+1 where 选项='" + radioButton2.Text + "'";
                }
                if (radioButton3.Checked)
                {
                    sqlstr = "update tb_vote set 票数=票数+1 where 选项='" + radioButton3.Text + "'";
                }
                if (radioButton4.Checked)
                {
                    sqlstr = "update tb_vote set 票数=票数+1 where 选项='" + radioButton4.Text + "'";
                }
                conn.Open();
                SqlCommand cmd = new(sqlstr, conn);
                int i = cmd.ExecuteNonQuery();
                conn.Close();
                if (i > 0)
                {
                    MessageBox.Show("投票成功");
                }
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
            }
        }

        private void Button2_Click(object sender, EventArgs e)
        {
            Form2 frm2 = new();
            frm2.Show();
        }
    }
}

       

//Form2.cs
//根据选票数据库，绘制直方图
using System.Data;
using System.Data.SqlClient;

namespace _12
{
    public partial class Form2 : Form
    {
        public Form2()
        {
            InitializeComponent();
        }

        private int Sum;
        SqlConnection? conn;
        private void CreateImage()
        {
            conn = new SqlConnection(@"server=DESKTOP-S11C97HSQLEXPRESS;database=db_CSharp;integrated security = True");
            conn.Open();
            SqlCommand cmd = new("select sum(票数) from tb_vote", conn);
            Sum = (int)cmd.ExecuteScalar();
            SqlDataAdapter sda = new("select * from tb_vote", conn);
            DataSet ds = new();
            sda.Fill(ds);
            int TP1 = Convert.ToInt32(ds.Tables[0].Rows[0][2].ToString());//第一个选项的票数
            int TP2 = Convert.ToInt32(ds.Tables[0].Rows[1][2].ToString());//第二个选项的票数
            int TP3 = Convert.ToInt32(ds.Tables[0].Rows[2][2].ToString());//第三个选项的票数
            int TP4 = Convert.ToInt32(ds.Tables[0].Rows[3][2].ToString());//第四个选项的票数
            float tp1 = Convert.ToSingle(Convert.ToSingle(TP1) * 100 / Convert.ToSingle(Sum));
            float tp2 = Convert.ToSingle(Convert.ToSingle(TP2) * 100 / Convert.ToSingle(Sum));
            float tp3 = Convert.ToSingle(Convert.ToSingle(TP3) * 100 / Convert.ToSingle(Sum));
            float tp4 = Convert.ToSingle(Convert.ToSingle(TP4) * 100 / Convert.ToSingle(Sum));
            int width = 300, height = 300;
            Bitmap bitmap = new(width, height);
            Graphics g = Graphics.FromImage(bitmap);
            try
            {
                g.Clear(Color.White);
                Brush brush1 = new SolidBrush(Color.LightGray);
                Brush brush2 = new SolidBrush(Color.Black);
                Brush brush3 = new SolidBrush(Color.Red);
                Brush brush4 = new SolidBrush(Color.Green);
                Brush brush5 = new SolidBrush(Color.Orange);
                Brush brush6 = new SolidBrush(Color.DarkBlue);
                Font font1 = new("Courier New", 16, FontStyle.Bold);
                Font font2 = new("Courier New", 8);
                g.FillRectangle(brush1, 0, 0, width, height);    //绘制背景浅灰色
                g.DrawString("投票结果", font1, brush2, new Point(90, 20));
                Point p1 = new(70, 50);
                Point p2 = new(230, 50);
                g.DrawLine(new Pen(Color.Black), p1, p2);
                //绘制文字
                g.DrawString("支付宝：", font2, brush2, new Point(45, 80));
                g.DrawString("微信支付：", font2, brush2, new Point(32, 110));
                g.DrawString("京东白条：", font2, brush2, new Point(32, 140));
                g.DrawString("小度钱包：", font2, brush2, new Point(32, 170));
                //绘制柱形图
                g.FillRectangle(brush3, 95, 80, tp1, 17);
                g.FillRectangle(brush4, 95, 110, tp2, 17);
                g.FillRectangle(brush5, 95, 140, tp3, 17);
                g.FillRectangle(brush6, 95, 170, tp4, 17);
                //绘制所有选项的票数显示
                g.DrawRectangle(new Pen(Color.Green), 10, 210, 280, 80);  //绘制范围框
                g.DrawString("支付宝：" + TP1.ToString() + "票", font2, brush2, new Point(15, 220));
                g.DrawString("微信支付：" + TP2.ToString() + "票", font2, brush2, new Point(150, 220));
                g.DrawString("京东白条：" + TP3.ToString() + "票", font2, brush2, new Point(15, 260));
                g.DrawString("小度钱包：" + TP4.ToString() + "票", font2, brush2, new Point(150, 260));
                pictureBox1.Image = bitmap;
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
            }
        }

        private void Form2_Paint(object sender, PaintEventArgs e)
        {
            CreateImage();
        }
        /// <summary>
        /// 设置窗体工作区大小，设置绘图板工作区，默认边距=8mm
        /// </summary>
        private void Form2_Load(object sender, EventArgs e)
        {
            ClientSize = new Size(324, 324);               //Form2工作区域大小
            StartPosition = FormStartPosition.CenterScreen;
            pictureBox1.Size = new Size(300, 300);      //pictureBox1尺寸，边距8mm
        }
    }
}

2.生成效果

 

二、折线图

        折线图可以很直观地反映出相关数据的变化趋势，折线图主要是通过绘制点和折线实现的。绘制点是通过Graphics类中的FillEllipse()方法实现的。绘制折线是通过Graphics类中的DrawLine()方法实现的。

        用DrawString()方法绘制文本时，文本的长度必须在所绘制的矩形区域内，如果超出区域，必须用format参数指定截断方式，否则将在最近的单词处截断。

1.示例源码

//折线图、趋势图
namespace _11
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Paint(object sender, PaintEventArgs e)
        {
            string[] month = ["一月", "二月", "三月", "四月", "五月", "六月", "七月", "八月", "九月", "十月", "十一月", "十二月"];
            float[] d = [20.5F, 60, 10.8F, 15.6F, 30, 70.9F, 50.3F, 30.7F, 70, 50.4F, 30.8F, 20];
            //画图初始化
            Bitmap bMap = new(500, 500);
            Graphics gph = Graphics.FromImage(bMap);
            gph.Clear(Color.White);
            PointF cPt = new(40, 420);                                                                                                                       //坐标原点
            PointF[] xPt = [new PointF(cPt.Y + 15, cPt.Y), new PointF(cPt.Y, cPt.Y - 4), new PointF(cPt.Y, cPt.Y + 4)];     //X轴箭头点
            PointF[] yPt = [new PointF(cPt.X, cPt.X - 15), new PointF(cPt.X - 4, cPt.X), new PointF(cPt.X + 4, cPt.X)];     //Y轴箭头点
            gph.DrawString("产品月产量趋势图", new Font("宋体", 14), Brushes.Blue, new PointF(cPt.X + 60, cPt.X));    //图标题
            //画X轴
            gph.DrawLine(Pens.Green, cPt.X, cPt.Y, cPt.Y, cPt.Y);     //X轴的长度=420= cPt.Y
            gph.DrawPolygon(Pens.Black, xPt);                         //X轴箭头
            gph.FillPolygon(new SolidBrush(Color.Pink), xPt);
            gph.DrawString("月份", new Font("宋体", 12), Brushes.Black, new PointF(cPt.Y + 10, cPt.Y + 10));
            //画Y轴
            gph.DrawLine(Pens.Black, cPt.X, cPt.Y, cPt.X, cPt.X);      //Y轴的长度=420-40=380
            gph.DrawPolygon(Pens.Black, yPt);                          //Y轴箭头
            gph.FillPolygon(new SolidBrush(Color.Black), yPt);
            gph.DrawString("单位(万)", new Font("宋体", 12), Brushes.Black, new PointF(0, 7));
            for (int i = 1; i <= 12; i++)
            {
                //画Y轴刻度
                if (i < 11)
                {
                    gph.DrawString((i * 10).ToString(), new Font("宋体", 11), Brushes.Black, new PointF(cPt.X - 30, cPt.Y - i * 30 - 6)); //间隔30单位打一个标记，工程值和坐标值间有个3倍的关系
                    gph.DrawLine(Pens.Black, cPt.X - 3, cPt.Y - i * 30, cPt.X, cPt.Y - i * 30);                                                               //间隔30单位刻一条标尺
                }
                //画X轴项目
                gph.DrawString(month[i - 1].AsSpan(0, 1), new Font("宋体", 11), Brushes.Black, new PointF(cPt.X + i * 30 - 5, cPt.Y + 5));    //间隔30单位打第一个字
                gph.DrawString(month[i - 1].AsSpan(1, 1), new Font("宋体", 11), Brushes.Black, new PointF(cPt.X + i * 30 - 5, cPt.Y + 20));   //间隔30单位打第二个字
                if (month[i - 1].Length > 2) gph.DrawString(month[i - 1].AsSpan(2, 1), new Font("宋体", 11), Brushes.Black, new PointF(cPt.X + i * 30 - 5, cPt.Y + 35));  //间隔30单位打第三个字
                //画数据点
                gph.DrawEllipse(Pens.Black, cPt.X + i * 30 - 1.5F, cPt.Y - d[i - 1] * 3 - 1.5F, 3, 3);                                                                  //以下Y坐标都要乘以3倍
                gph.FillEllipse(new SolidBrush(Color.Black), cPt.X + i * 30 - 1.5F, cPt.Y - d[i - 1] * 3 - 1.5F, 3, 3);
                //画数据值
                gph.DrawString(d[i - 1].ToString(), new Font("宋体", 11), Brushes.Black, new PointF(cPt.X + i * 30, cPt.Y - d[i - 1] * 3));
                //画折线
                if (i > 1) gph.DrawLine(Pens.Red, cPt.X + (i - 1) * 30, cPt.Y - d[i - 2] * 3, cPt.X + i * 30, cPt.Y - d[i - 1] * 3);
            }
            pictureBox1.Image = bMap;
        }   
    }
}

2.生成效果

 

三、饼形图 

        饼形图可以很直观地查看不同数据所占的比例情况，通过Graphics类中的FillPie()方法，可以方便地绘制出饼形图。

public void FillPie (Brush brush,int x,int y,int width,int height,int startAngle,int sweepAngle)

参    数

说    明

  brush

确定填充特性的Brush

   X

边框左上角的x坐标，该边框定义扇形区所属的椭圆

  y

边框左上角的y坐标，该边框定义扇形区所属的椭圆

  width

边框的宽度，该边框定义扇形区所属的椭圆

  heigh

边框的高度，该边框定义扇形区所属的椭圆

  startAngle

从x轴沿顺时针方向旋转到扇形区第一个边所测得的角度(以度为单位)

  sweepAngle

从startAngle参数沿顺时针方向旋转到扇形区第二个边所测得的角度(以度为单位)

1.示例源码

         ,NET 8.0的项目中需要使用NuGet程序包：system.data.sqlclient.4.8.5.nupkg或更高级版本。否则不能使用SqlClient的方法。

//绘制饼图
using System.Data.SqlClient;
using System.Data;

namespace _10
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            ClientSize = new Size(420, 470);           
            StartPosition = FormStartPosition.CenterScreen;
            Text = "绘制饼图";
            pictureBox1.Dock = DockStyle.Fill;

        }

        private void CreateImage()
        {
            //连数据库
            SqlConnection conn = new(@"server=DESKTOP-S11C97HSQLEXPRESS;database=db_CSharp;integrated security = True");
            conn.Open();
            //计算公司员工总和
            string str2 = "SELECT SUM(人数) AS Number FROM tb_age";
            SqlCommand cmd = new(str2, conn);
            int Sum = Convert.ToInt32(cmd.ExecuteScalar());
            SqlDataAdapter sda = new("select * from tb_age", conn);
            DataSet ds = new();
            sda.Fill(ds);
            //获取20-25岁员工人数
            int man20to25 = Convert.ToInt32(ds.Tables[0].Rows[0][2].ToString());
            //获取26-30岁员工人数
            int man26to30 = Convert.ToInt32(ds.Tables[0].Rows[1][2].ToString());
            //获取31-40岁员工人数
            int man31to40 = Convert.ToInt32(ds.Tables[0].Rows[2][2].ToString());
            //创建画图对象
            int width = 400, height = 450;
            Bitmap bitmap = new(width, height);
            Graphics g = Graphics.FromImage(bitmap);
            try
            {
                //清空背景色
                g.Clear(Color.White);
                Pen pen1 = new(Color.Red);
                Brush brush1 = new SolidBrush(Color.PowderBlue);
                Brush brush2 = new SolidBrush(Color.Blue);
                Brush brush3 = new SolidBrush(Color.Wheat);
                Brush brush4 = new SolidBrush(Color.Orange);
                Font font1 = new("Courier New", 16, FontStyle.Bold);
                Font font2 = new("Courier New", 8);
                g.FillRectangle(brush1, 0, 0, width, height);    //绘制背景图
                g.DrawString("公司员工年龄比例饼形图", font1, brush2, new Point(80, 20));  //书写标题
                int piex = 100, piey = 60, piew = 200, pieh = 200;
                //20-25岁员工在圆中分配的角度
                float angle1 = Convert.ToSingle((360 / Convert.ToSingle(Sum)) * Convert.ToSingle(man20to25));
                //26-30岁员工在圆中分配的角度
                float angle2 = Convert.ToSingle((360 / Convert.ToSingle(Sum)) * Convert.ToSingle(man26to30));
                //31-40岁员工在圆中分配的角度
                float angle3 = Convert.ToSingle((360 / Convert.ToSingle(Sum)) * Convert.ToSingle(man31to40));
                g.FillPie(brush2, piex, piey, piew, pieh, 0, angle1);       //绘制20-25岁员工所占比例
                g.FillPie(brush3, piex, piey, piew, pieh, angle1, angle2);  //绘制26-30岁员工所占比例
                g.FillPie(brush4, piex, piey, piew, pieh, angle1 + angle2, angle3);  //绘制31-40岁员工所占比例
                //绘制标识
                g.DrawRectangle(pen1, 50, 300, 310, 130);  //绘制范围框
                g.FillRectangle(brush2, 90, 320, 20, 10);  //绘制小矩形
                g.DrawString("20-25岁员工占公司总人数比例:" + Convert.ToSingle(man20to25) * 100 / Convert.ToSingle(Sum) + "%", font2, brush2, 120, 320);
                g.FillRectangle(brush3, 90, 360, 20, 10);
                g.DrawString("26-30岁员工占公司总人数比例:" + Convert.ToSingle(man26to30) * 100 / Convert.ToSingle(Sum) + "%", font2, brush2, 120, 360);
                g.FillRectangle(brush4, 90, 400, 20, 10);
                g.DrawString("31-40岁员工占公司总人数比例:" + Convert.ToSingle(man31to40) * 100 / Convert.ToSingle(Sum) + "%", font2, brush2, 120, 400);
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
            }
            pictureBox1.Image = bitmap;
        }

        private void Form1_Paint(object sender, PaintEventArgs e)
        {
            CreateImage();
        }
    }
}

2.生成效果

 

原文地址:https://blog.csdn.net/wenchm/article/details/134725815

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