C# Chart control : X value of a horizontal bar chart is 0 for all points in the serie

Question

I have a horizontally stacked bar chart in my app, and I'm trying to figure out how to get the X axis value when the user clicks on a bar. The problem is when I look at the values at runtime, the Y values are fine but the X values are all 0.

Screen capture

In the image above, light blue bars are from Series[0] and represent the MTD sales and the darker ones from Series[1] represent last year's sales for the same month. My goal is that when the user double-clicks on a bar, he is taken to the detailed sales report for that salesperson.

I haven't tried switching my chart to a regular bar chart because this is what I will need to look like in the end. But I'm starting to wonder if the reason I'm getting all 0's in the XValue field is because of this or because I am using strings as the type of value.

Has anyone ever encountered this or have any clues as to how to fix it?

Screen capture of points at runtime

Answer 1

OK so I finally managed to put custom labels on the chart using the Chart.Customize event.

Here is the data I am using for this chart:

Vendeur     |   Total    |    idDepartement   |   idEmploye   | TotalLastYear
Ghislain        5256.30       1                   56                0.00
Kim            12568.42       1                    1            74719.18
Philippe       17565.27       1                   44            38454.85

I changed X axis XValueType to Double, and the XValueMember to idEmploye.

Result

As you can see, it's not very user friendly to have employee id's on a chart. This is where the Customize event gets useful.

Here is my event:

private void chart1_Customize(object sender, EventArgs e)
    {
        // Set X axis interval to 1, label will be centered (between 0.5 and 1.5)
        chart1.ChartAreas[0].AxisX.Interval = 1;
        double startOffset = 0.5;
        double endOffset = 1.5;

        chart1.ChartAreas[0].AxisX.CustomLabels.Clear();

        // Cycle through chart Datapoints in first serie
        foreach (System.Windows.Forms.DataVisualization.Charting.DataPoint pt in chart1.Series[0].Points)
        {

            // First get the dataset used for the chart (from its bindingsource)
            DataSet dsSales = (DataSet)bsViewVentesParUtilisateurSignsMoisCourant.DataSource;

            // Second get the datatable from that dataset based on the datamember 
            // property of the bindingsource
            DataTable dtSales = (DataTable)dsSales.Tables[bsViewVentesParUtilisateurSignsMoisCourant.DataMember];

            // Get a dataview and filter its result based on the current point's XValue
            DataView dv = new DataView(dtSales);
            dv.RowFilter = "idEmploye=" + pt.XValue.ToString();

            // Get the "Salesperson" (or "Vendeur") column value from the first result
            // (other rows will have the same value but row 0 is safe)
            string firstname = dv.ToTable().Rows[0].Field<string>("Vendeur").ToString();

            // Create new customlabel and add it to the X axis
            CustomLabel salespersonLabel = new CustomLabel(startOffset, endOffset, firstname, 0, LabelMarkStyle.None);
            chart1.ChartAreas[0].AxisX.CustomLabels.Add(salespersonLabel);
            startOffset += 1;
            endOffset += 1;
        }
    }

Final result

I am very happy with the result. And now when I double-click on a bar in the chart, I can get the employee id from the X value and generate the code to get the detailed sales report for that person for the given month.