仅使用一列从数据库中绘制数据图表

Question

我想创建一个图表来读取我数据库中的 Extra_Process 列。它只有两个值。 “加急订单”和“正常订单”

我有这个代码...

chart1.Series["Order Process"].Points.Clear();
        MySqlCommand cmd = new MySqlCommand("SELECT Extra_Process, sum(Extra_Process) qty FROM sketchit.monitoring GROUP BY Extra_Process; ", dc.con);
        MySqlDataReader myreader;
        try
        {
            dc.con.Open();
            myreader = cmd.ExecuteReader();
            while (myreader.Read())
            {

                this.chart1.Series["Order Process"].Points.AddXY(myreader.GetString("Extra_Process"), myreader.GetInt32("qty"));
                chart1.ChartAreas["ChartArea1"].AxisX.Interval = 1;



            }
        }
        catch (Exception ex)
        {
            MessageBox.Show(ex.Message);
        }
        dc.con.Close();

我想知道我的专栏中有多少紧急订单和普通订单，但没有显示任何结果。我不知道该怎么办。

here's the pic

Answer 1

步骤：

1. 查询并获取 RushOrder 和 NormalOrder 的 Count 值。
2. 获得两个计数后，将其传递给以下函数以生成PieChart

 private void btnChart_Click(object sender, EventArgs e)
 {
     //Make your Query , Get Count Value for RushOrder and NormalOrder
     //Check for Null Value
     //Pass the Count to the DrawPieChart() function


     //Sample Chart Generation 
     int nRushOrderCount = Convert.ToInt32(txtRushOrder.Text);
     int nNormalOrderCount = Convert.ToInt32(txtNormalOrder.Text);
     DrawPieChart(nRushOrderCount, nNormalOrderCount);
  }

  private void DrawPieChart(int nRushOrder, int nNormalOrder)
  {
     //reset your chart series and legends
     chart1.Series.Clear();
     chart1.Legends.Clear();

     //Add a new Legend(if needed) and do some formating
     chart1.Legends.Add("MyLegend");
     chart1.Legends[0].LegendStyle = LegendStyle.Table;
     chart1.Legends[0].Docking = Docking.Bottom;
     chart1.Legends[0].Alignment = StringAlignment.Center;
     chart1.Legends[0].Title = "Order Details";
     chart1.Legends[0].BorderColor = Color.Black;

     //Add a new chart-series
     string seriesname = "MySeriesName";
     chart1.Series.Add(seriesname);
     //set the chart-type to "Pie"
     chart1.Series[seriesname].ChartType = SeriesChartType.Pie;

     //Add some datapoints so the series. in this case you can pass the values to this method
     chart1.Series[seriesname].Points.AddXY("Rush Order", nRushOrder);
     chart1.Series[seriesname].Points.AddXY("Normal Order", nNormalOrder);

     chart1.Series[seriesname].IsValueShownAsLabel = true;
  }