在 MS 图表中添加注释（例如 (10, 20) (20, 39) 等）和水平滚动条

Question

I want to add text(say, annotations) in MS chart(winforms) like (10, 20) , (30, 40) where I already have a scroll bar.

I can able to draw strings(graphics.drawstring) in Chart, but on scrolling the horizontal scroll bar, the text which I have drawn remains static and immovable.

On scrolling the scrollbar, the text which I have drawn also should move along with my horizontal scrolling.

My code follows:

 chart2.BorderSkin.SkinStyle = BorderSkinStyle.Emboss;
 chart2.BorderlineColor      = System.Drawing.Color.FromArgb(26, 59, 105);
 chart2.BorderlineWidth = 3;
 chart2.BackColor       = Color.White;

 chart2.ChartAreas.Add("chtArea");
 chart2.ChartAreas[0].AxisX.Title = "Category Name";
 chart2.ChartAreas[0].AxisX.TitleFont = 
        new System.Drawing.Font("Verdana", 11, System.Drawing.FontStyle.Bold);
 chart2.ChartAreas[0].AxisY.Title = "UnitPrice";
 chart2.ChartAreas[0].AxisY.TitleFont = 
        new System.Drawing.Font("Verdana", 11, System.Drawing.FontStyle.Bold);
 chart2.ChartAreas[0].BorderDashStyle = ChartDashStyle.Solid;
 chart2.ChartAreas[0].BorderWidth = 2;

 chart2.ChartAreas["chtArea"].AxisX.ScrollBar.Enabled = true;
 chart2.ChartAreas["chtArea"].CursorX.IsUserEnabled = true;
 chart2.ChartAreas["chtArea"].CursorX.IsUserSelectionEnabled = true;
 chart2.ChartAreas["chtArea"].AxisX.ScaleView.Zoomable = false;
 chart2.ChartAreas["chtArea"].AxisX.ScrollBar.IsPositionedInside = true;
 chart2.ChartAreas["chtArea"].AxisX.ScaleView.Size = 20;
 chart2.ChartAreas[0].AxisX.ScaleView.SmallScrollSizeType = DateTimeIntervalType.Seconds;
 chart2.ChartAreas[0].AxisX.ScaleView.SmallScrollSize = 1;

 chart2.Legends.Add("UnitPrice");
 chart2.Series.Add("UnitPrice");
 chart2.Series[0].ChartType = SeriesChartType.Line;

 Random rand = new Random();
 var valuesArray = Enumerable.Range(0, 500).Select(x => rand.Next(0, 100)).ToArray();

 for (int i = 0; i < 500; i++)
 {                         
      chart2.Series["UnitPrice"].Points.AddXY(i+10, valuesArray[i]);               
 }

I tried TextAnnotaions, Line annotations, etc Nothing helped me.

Then I tried drawing dynamic labels inside MS chart also. Labels remain immovable while scrolling horizontal scroll bar.

This code works perfectly in your machine also.

Answer 1

Sounds a lot as if you want to add TextAnnotations .

If you want them to stick with your data points you should anchor them to the points they shall stay with.

Here are a few examples:

    // directly anchored to a point
    TextAnnotation TA1 = new TextAnnotation();
    TA1.Text = "DataPoint 222";
    TA1.SetAnchor(chart2.Series["UnitPrice"].Points[222]);
    chart2.Annotations.Add(TA1);

    // anchored to a point but shifted down
    TextAnnotation TA2 = new TextAnnotation();
    TA2.Text = "DataPoint 111";
    TA2.AnchorDataPoint = chart2.Series["UnitPrice"].Points[111];
    TA2.AnchorY = 0;   

    chart2.Annotations.Add(TA2);

    // this one is not anchored on a point:
    TextAnnotation TA3 = new TextAnnotation();
    TA3.Text = "At 50% width BC";
    TA3.AnchorX = 50;  // 50% of chart width
    TA3.AnchorY = 20;  // 20% of chart height, from top!
    TA3.Alignment = ContentAlignment.BottomCenter;  // try a few!

    chart2.Annotations.Add(TA3);

By default they either anchor to DataPoints or are positioned in % of the chart size.

It is also possible to set the positions according to pixel coordinates, but for this you need to calculate the positions each time the chart changes its view!

See here for an example how to transform chart data positions to chart control coordinates and vice versa.. (Not really recommended, though)