如何使用c#创建图表

Question

我需要根据数据创建一个图表,我可以从我拥有的6个组合框中获取.

组合框中的数据是数字.一旦我在组合框中选择了所需的数字,然后按一个按钮,根据这些值创建图表.

我的问题是我只能做一次.一旦我更改了组合框中的值并再次单击该按钮,我会收到一个异常.

我知道每次按下按钮我都需要创建一个新图表的实例,但我不知道如何.

private void button1_Click(object sender, EventArgs e)
{
    chart1.ChartAreas.Add("chart");
    chart1.ChartAreas["chart"].AxisX.Minimum = 0;
    chart1.ChartAreas["chart"].AxisX.Maximum = 20;
    chart1.ChartAreas["chart"].AxisX.Interval = 1;

    chart1.ChartAreas["chart"].AxisY.Minimum = 0;
    chart1.ChartAreas["chart"].AxisY.Maximum = 100;
    chart1.ChartAreas["chart"].AxisY.Interval = 5;

    chart1.Series.Add("xxx");
    chart1.Series.Add("yyy");

    chart1.Series["xxx"].Color = Color.Black;
    chart1.Series["yyy"].Color = Color.Red;

    chart1.Series["xxx"].ChartType = System.Windows.Forms.DataVisualization.Charting.SeriesChartType.Line;
    chart1.Series["yyy"].ChartType = System.Windows.Forms.DataVisualization.Charting.SeriesChartType.Line;

    chart1.Series["xxx"].Points.AddXY(comboBox1.Text, comboBox4.Text);
    chart1.Series["yyy"].Points.AddXY(comboBox1.Text, comboBox4.Text);

    chart1.Series["xxx"].Points.AddXY(comboBox2.Text, comboBox5.Text);
    chart1.Series["yyy"].Points.AddXY(comboBox1.Text, comboBox4.Text);

    chart1.Series["xxx"].Points.AddXY(comboBox3.Text, comboBox6.Text);
    chart1.Series["yyy"].Points.AddXY(comboBox1.Text, comboBox4.Text);
}

Answer 1

尝试将chart1设置为Chart的新实例(我假设它是什么!)

所以它会是这样的:

 private void button1_Click(object sender, EventArgs e) 
 { 
    chart1 = new Chart();
    chart1.ChartAreas.Add("chart"); 
    chart1.ChartAreas["chart"].AxisX.Minimum = 0; 
    chart1.ChartAreas["chart"].AxisX.Maximum = 20; 
    chart1.ChartAreas["chart"].AxisX.Interval = 1; 

    chart1.ChartAreas["chart"].AxisY.Minimum = 0; 
    chart1.ChartAreas["chart"].AxisY.Maximum = 100; 
    chart1.ChartAreas["chart"].AxisY.Interval = 5; 

    chart1.Series.Add("xxx"); 
    chart1.Series.Add("yyy"); 

    chart1.Series["xxx"].Color = Color.Black; 
    chart1.Series["yyy"].Color = Color.Red; 

    chart1.Series["xxx"].ChartType = System.Windows.Forms.DataVisualization.Charting.SeriesChartType.Line; 
    chart1.Series["yyy"].ChartType = System.Windows.Forms.DataVisualization.Charting.SeriesChartType.Line; 

    chart1.Series["xxx"].Points.AddXY(comboBox1.Text, comboBox4.Text); 
    chart1.Series["yyy"].Points.AddXY(comboBox1.Text, comboBox4.Text); 

    chart1.Series["xxx"].Points.AddXY(comboBox2.Text, comboBox5.Text); 
    chart1.Series["yyy"].Points.AddXY(comboBox1.Text, comboBox4.Text); 

    chart1.Series["xxx"].Points.AddXY(comboBox3.Text, comboBox6.Text); 
    chart1.Series["yyy"].Points.AddXY(comboBox1.Text, comboBox4.Text); 
}