Attaching a Textbox to a point or line on a chart in Excel/VBA

Solution 1:

To solve your question you need to get the left & top position of two objects:

1. chart itself, which position is set in relation to top-left corner of sheet range area
2. point in series which position is set in relation to top-left corner of chart

Combination of both result with the following code (fixed parameters-required changes to your situation, could be more dynamic with loop)

Sub Add_Text_to_point()

    Dim tmpCHR As ChartObject
    Set tmpCHR = Sheet1.ChartObjects(1) 'put index of your chartobject here

    'for first serie, for point 2nd here
    '(change accordingly to what you need)
    With tmpCHR.Chart.SeriesCollection(1).Points(2)

        Sheet1.Shapes.AddTextbox(msoTextOrientationHorizontal, _
                .Left + tmpCHR.Left, _
                .Top + tmpCHR.Top, _
                100, 15) _
                .TextFrame.Characters.Text = "Temperature"
    End With

End Sub

After result presenting the picture below.

Solution 2:

Another option would be to use the data labels of Excel. I see two more elegant options:

1. Make a new data series with just one entry in your chart, give the series the coordinates and the name of the label you want to see. Now activate the marker option for the series (if not done already), right-click on the data point, click "add data labels". Now you'll see the y-Value of the point. By right-clicking again and choosing "Format Data Labels" you can change the text to the series name, also the position, the border, etc. are modifiable. Below an example with two data points. You could delete the second point, the line and the marker but like this you see how it works.
2. Similarly to the solution from KazJaw you can use the actual data points of your series for attaching custom data labels. This requires some coding, I used this for the chart named "Topview" and wrote percentages next to the data point

Sub Add_Text_to_data_points()
    percentages(1) = 0.1
    percentages(2) = 0.23
    '.... further entries
    chartNumber = findChartNumber("Topview")
    collNumber = 12 ' index of the "points" series
    Set tmpCHR = ActiveSheet.ChartObjects(chartNumber) 
    For i = 1 To tmpCHR.Chart.SeriesCollection(collNumber).Points.count
    With tmpCHR.Chart.SeriesCollection(collNumber).Points(i)
        If percentages(i) <> 0 Then
            .DataLabel.Text = format(percentages(i), "0%")
        End If
    End With
    Next
End Sub