Inserting TextAnnotation in graph c#

Question

I creating simple graph with line as average (sample only), I have a code in HorizontalLineAnnotation (color red line) and TextAnnotation but the problem is that, the TextAnnotation not working properly.

Here my code in HorizontalLineAnnotation and TextAnnotation .

private void annptaion()
{
//insert line
HorizontalLineAnnotation hl = new HorizontalLineAnnotation();
                    hl.AllowMoving = false;
                    hl.IsInfinitive = true;
                    //hl.LineColor = System.Drawing.Color.Red;
                    hl.AnchorY = Convert.ToDouble(2);//row line
                    hl.AxisX = chart1.ChartAreas[0].AxisX;
                    hl.AxisY = chart1.ChartAreas[0].AxisY;
                    hl.ClipToChartArea = chart1.ChartAreas[0].Name; hl.LineColor = Color.Red; hl.LineWidth = 1;//make line
                    hl.IsSizeAlwaysRelative = false;
                    chart1.Annotations.Add(hl);

//insert text
TextAnnotation ta = new TextAnnotation();
                    
                    ta.AxisX = chart1.ChartAreas[0].AxisX;
                    ta.AxisY = chart1.ChartAreas[0].AxisY;
                    ta.IsSizeAlwaysRelative = false;
                    ta.AnchorAlignment = ContentAlignment.BottomLeft;
                    ta.Text = "average (sample)";
                    ta.ClipToChartArea = chart1.ChartAreas[0].Name; ta.ForeColor = Color.Red;
                    chart1.Annotations.Add(ta);
}

I use the code above for displaying text in the line, but it's not working properly. I want to display the text either inside of the graph or outside of the graph.

Answer 1

Hi @YUI-012 , Welcome to Microsoft Q&A,

It seems that you can achieve the desired effect in two ways:

One is to anchor to a point to achieve the effect inside the table, and the other is to anchor to the table to achieve the effect outside the table:

using System.Drawing;
using System.Windows.Forms;
using System.Windows.Forms.DataVisualization.Charting;

namespace xxx
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
            AddAnnotationsToChart();
        }
        private void AddAnnotationsToChart()
        {
            Series series = new Series("SampleSeries");
            series.ChartType = SeriesChartType.Line;

            series.Points.AddXY(1, 1);
            series.Points.AddXY(2, 2);
            series.Points.AddXY(3, 2);
            series.Points.AddXY(4, 3);  
            series.Points.AddXY(5, 4); 
            chart1.Series.Add(series);

            HorizontalLineAnnotation hl = new HorizontalLineAnnotation();
            hl.AllowMoving = false;
            hl.IsInfinitive = true;
            hl.LineColor = Color.Red;
            hl.AnchorY = 3.5;  
            hl.AxisX = chart1.ChartAreas[0].AxisX;
            hl.AxisY = chart1.ChartAreas[0].AxisY;
            hl.ClipToChartArea = chart1.ChartAreas[0].Name;
            hl.LineWidth = 1;
            chart1.Annotations.Add(hl);

            TextAnnotation ta = new TextAnnotation();
            ta.Text = "Annotation Text";
            ta.ForeColor = Color.Red;
            ta.SetAnchor(chart1.Series["SampleSeries"].Points[4]);
            chart1.Annotations.Add(ta);

            TextAnnotation ta2 = new TextAnnotation();
            ta2.Text = "At 80% width BC";
            ta2.AnchorX = 80;  // 80% of chart width
            ta2.AnchorY = 30;  // 30% of chart height, from top
            chart1.Annotations.Add(ta2);

            chart1.ChartAreas[0].AxisX.Minimum = 0;
            chart1.ChartAreas[0].AxisX.Maximum = 6;
            chart1.ChartAreas[0].AxisY.Minimum = 0;
            chart1.ChartAreas[0].AxisY.Maximum = 5;

            chart1.Invalidate();
        }
    }
}

Best Regards,

Jiale

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