How to change chart series color

问题

I have a single series which populates my chart with records from a database. Seven records are been displayed but in the sanme color.

I' trying to change each bar color without success

Below are the lines i tried but i gave me one big green bar (:

        private void button1_Click(object sender, EventArgs e)
    {
        /*First empty the chart2 to fire the current data*/
        if (cbChart.SelectedItem == null)
        {
            chart.Visible = false;
            chart.Controls.Clear();
        }
        else
            //pnchart.Controls.Clear();
        chart.Visible = true;
        chart.Titles.Clear();


        /*Add a new title*/
        Title bezeichung = new Title("Finance" + Environment.NewLine + "(GWU)", Docking.Top, new Font("Yu Gothic", 8, FontStyle.Bold), Color.Black);
        chart.Titles.Add(bezeichung);          
        chart.Titles.Add(bezeichung2);



         if (cbChart.SelectedItem != null)
        {
      string S =    ConfigurationManager.ConnectionStrings[""].ConnectionString;
      SqlConnection con = new SqlConnection(S);
      SqlCommand cmd = new SqlCommand();
      cmd.Connection = con;
      cmd.CommandType = CommandType.StoredProcedure;
      cmd.CommandText = ("[dbo].[storedprocedure]");
      cmd.Parameters.AddWithValue("@Table_Name", cbChart.SelectedValue.ToString());
      SqlDataReader myReader;  // DataReader to just read Data from the Datbase

            try
            {
                //DO SOMETHING
                con.Open();
                myReader = cmd.ExecuteReader();

                while (myReader.Read())
                {

                   //Parameters (Seriesname, x-axis data & y-axis data)
                    this.chart.Series["Series"].Points.AddXY(myReader["Finance"], myReader["GWU"]);

                    // remove grid lines
                    chart.ChartAreas[0].AxisX.MajorGrid.LineWidth = 0;
                    chart.ChartAreas[0].AxisY.MajorGrid.LineWidth = 0;
                    chart.ChartAreas[0].AxisX.LabelStyle.Angle = -45;

      chart.Series["series1"].Points[0].Color = Color.Green;
      chart.Series["series1"].Points[1].Color = Color.Red;
      chart.Series["series1"].Points[2].Color = Color.PowderBlue;
      chart.Series["series1"].Points[3].Color = Color.Peru;
      chart.Series["series1"].Points[4].Color = Color.Pink;
      chart.Series["series1"].Points[5].Color = Color.Purple;
                }

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

         else
         {

MessageBox.Show("Bitte ", "Info", MessageBoxButtons.OK, MessageBoxIcon.Warning);
         }

    }

That’s the error message I received after running it: The index lies outside the valid range, index must not be negative and must be lower than the size of the list

And the chart after hitting the button:

回答1:

You are trying to change the color of points before they are added in the series. Move the below block out of the while loop and check if enough points exists in series before you try to access by index,

  chart.Series["series1"].Points[0].Color = Color.Green;
  chart.Series["series1"].Points[1].Color = Color.Red;
  chart.Series["series1"].Points[2].Color = Color.PowderBlue;
  chart.Series["series1"].Points[3].Color = Color.Peru;
  chart.Series["series1"].Points[4].Color = Color.Pink;
  chart.Series["series1"].Points[5].Color = Color.Purple;

Below are the changes you need to make in code,

while (myReader.Read())
{
//Parameters (Seriesname, x-axis data & y-axis data)
this.chart.Series["Series"].Points.AddXY(myReader["Finance"], myReader["GWU"]);

}

if(chart.ChartAreas.Count > 0)
{
chart.ChartAreas[0].AxisX.MajorGrid.LineWidth = 0;
chart.ChartAreas[0].AxisY.MajorGrid.LineWidth = 0;
chart.ChartAreas[0].AxisX.LabelStyle.Angle = -45;
}


if(chart.Series["series1"].Points.Count > 5)
{
chart.Series["series1"].Points[0].Color = Color.Green;
chart.Series["series1"].Points[1].Color = Color.Red;
chart.Series["series1"].Points[2].Color = Color.PowderBlue;
chart.Series["series1"].Points[3].Color = Color.Peru;
chart.Series["series1"].Points[4].Color = Color.Pink;
chart.Series["series1"].Points[5].Color = Color.Purple;
}

来源：https://stackoverflow.com/questions/29302663/how-to-change-chart-series-color

标签

winforms

mschart