WinForm绘制折线统计图

效果图

 

 public partial class 折线图 : Form
    {
        string[] strYue = { "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" };
        string[] strShuLiang = { "100", "68", "87", "67", "10", "50", "90", "60", "20", "30", "78", "56" };
        DataTable dt = new DataTable();
        public 折线图()
        {
            InitializeComponent();
            DataColumn dc = new DataColumn("YueFen", typeof(string));
            dt.Columns.Add(dc);
            DataColumn dc1 = new DataColumn("ShuLiang", typeof(string));
            dt.Columns.Add(dc1);
            //加载数据
            for (int i = 0; i < 12; i++)
            {
                DataRow dr = dt.NewRow();
                dr["YueFen"] = strYue[i];
                dr["ShuLiang"] = strShuLiang[i];
                dt.Rows.Add(dr);
            }
            comboBox1.SelectedItem = "上半年";
            btn_ChaXun_Click(null,null);
           
        }

        private void btn_ChaXun_Click(object sender, EventArgs e)
        {

            List<Point> pos = new List<Point>();
            int i1, i2;
            Bitmap bitM = new Bitmap(this.panel1.Width, this.panel1.Height);
            Graphics g = Graphics.FromImage(bitM);
            g.Clear(Color.White);
            Brush b = new SolidBrush(Color.Blue);
            Font f = new Font("Arial", 9, FontStyle.Regular);
            Pen p = new Pen(b);
            //绘制横线
            //找出折线统计图的0,0点
            int ZheX = 40;
            int ZheY = 0;
            int y = 40;

            for (int i = 0; i < 6; i++)
            {
                g.DrawLine(new Pen(Color.Red), 40, y, 260, y);
                g.DrawString(i * 20 + "", new Font("宋体", 12, FontStyle.Regular), new SolidBrush(Color.Red), 10, this.panel1.Height - y - 32);
                y += 40;

            }
            ZheY = y - 40;
            //绘制竖线
            for (int i = 0; i < 6; i++)
            {
                g.DrawLine(new Pen(Color.Red), ZheX + 40 * i, 20, 40 + 40 * i, 240);
                //  g.DrawString(i * 20 + "", new Font("宋体", 12, FontStyle.Regular), new SolidBrush(Color.Red), 10, this.panel1.Height - y - 32);
                if (comboBox1.Text == "上半年")
                {
                    g.DrawString(strYue[i], new Font("宋体", 12, FontStyle.Regular), new SolidBrush(Color.Red), 20 + 40 * i, ZheY + 8);
                }
                else
                {
                    g.DrawString(strYue[6 + i], new Font("宋体", 12, FontStyle.Regular), new SolidBrush(Color.Red), 20 + 40 * i, ZheY + 8);
                }

            }

            if (comboBox1.Text == "上半年")
            {
                //加载右侧List
                listBox1.Items.Clear();
                for (int i = 0; i < 6; i++)
                {

                    listBox1.Items.Add(strYue[i] + " : " + strShuLiang[i] + "箱");

                }
                i1 = 0;
                i2 = 6;

            }
            else
            {
                //加载右侧List
                listBox1.Items.Clear();
                for (int i = 6; i < 12; i++)
                {

                    listBox1.Items.Add(strYue[i] + " : " + strShuLiang[i] + "箱");

                }
                i1 = 6;
                i2 = 12;
            }
            for (int i = i1; i < i2; i++)
            {
                //根据新的0,0点和横线的增量获取新的Y值
                //新的Y值=数量/绘制的文字数量的增量（0，20，40）  *  40(绘制的图中的px的增量，40px)
                decimal d = (decimal.Parse(dt.Rows[i]["ShuLiang"].ToString()) / 20) * 40;
                int d1 = (int)d;
                Point p1;
                if (i1 >= 6)
                {
                     p1 = new Point((i + 1-6) * 40, ZheY - d1);
                }
                else
                {
                     p1 = new Point((i + 1) * 40, ZheY - d1);
                }
               
                pos.Add(p1);
            }
          
           

            //连线  
            for (int i = 0; i < 5; i++)
            {
                g.DrawLine(p, pos[i], pos[i + 1]);
            }
            this.panel1.BackgroundImage = bitM;
        }
       
    }