Type Expected error when attempting to use Chart

[AntonyL]

Hi Guys,

I am getting a Type Expected error when I am using the following simple line of code

Dim chart as new Chart()

I have searched extensively but am unable to find out why the error occurs or what to do about it.
I am trying to create a simple XY Column Graph with Positive(Blue) and negative(Red) values on the Y axis and Time on the X axis

Here is the code so far.

Imports System.Security.Cryptography.X509Certificates
Imports System.Windows.Forms.DataVisualization.Charting

Public Class Form1 'ColumnChartExample
    ' summary
    ' Windows Forms example for a column chart with time (seconds) on the X-axis
    ' and positive/negative values on the Y-axis.
    ' Positive values are displayed in blue; negative values are displayed in red.


    Inherits Form

    Dim chart As New Chart()
    Private chartArea As ChartArea
    Private series As Series

    Public AnalysisValues(10) As Integer
    Private Sub Form_Load()

    End Sub
    Private Sub Data()
        AnalysisValues = {1, 3, 4, 3, 2, 1, 0, -1, -3, -4}
    End Sub

    Public Sub New()
        ' Initialize the form
        Me.Text = "Column Chart Example"
        Me.Size = New Drawing.Size(900, 600)

        ' Create the chart control
        chart = New Chart()
        chart.Dock = DockStyle.Fill

        ' Create and configure the chart area
        chartArea = New ChartArea("MainArea")
        chartArea.AxisX.Title = "Time (seconds)"
        chartArea.AxisY.Title = "Value"

        ' Add a zero-crossing line on the Y-axis for clarity
        chartArea.AxisX.Crossing = 0
        chartArea.AxisY.Crossing = 0
        chartArea.AxisY.IntervalAutoMode = IntervalAutoMode.VariableCount

        ' Optional: customize grid lines
        chartArea.AxisX.MajorGrid.LineColor = Drawing.Color.LightGray
        chartArea.AxisY.MajorGrid.LineColor = Drawing.Color.LightGray

        chart.ChartAreas.Add(chartArea)

        ' Create and configure the data series
        series = New Series("DataSeries")
        series.ChartType = SeriesChartType.Column
        series.ChartArea = "MainArea"
        series.IsValueShownAsLabel = True
        series.LabelForeColor = Drawing.Color.Black

        ' Sample data: time in seconds and corresponding positive/negative values
        Dim data As New List(Of Tuple(Of Double, Double)) From {
            Tuple.Create(1.0, 15.0),
            Tuple.Create(2.0, -8.0),
            Tuple.Create(3.0, 22.0),
            Tuple.Create(4.0, -5.0),
            Tuple.Create(5.0, -18.0),
            Tuple.Create(6.0, 7.0),
            Tuple.Create(7.0, 0.0),
            Tuple.Create(8.0, -12.0),
            Tuple.Create(9.0, 30.0),
            Tuple.Create(10.0, -3.0)
        }

        ' Populate the series and color each column based on positive/negative value
        For Each point In data
            Dim dp As New DataPoint()
            dp.SetValueXY(point.Item1, point.Item2)
            dp.AxisLabel = point.Item1.ToString() ' X-axis label shows time in seconds

            ' Color logic: blue for positive, red for negative
            If point.Item2 >= 0 Then
                dp.Color = Drawing.Color.Blue
            Else
                dp.Color = Drawing.Color.Red
            End If

            series.Points.Add(dp)
        Next

        chart.Series.Add(series)

        ' Add a legend for clarity
        Dim legend As New Legend("MainLegend")
        legend.Docking = Docking.Top
        chart.Legends.Add(legend)

        ' Add the chart to the form
        Me.Controls.Add(chart)
    End Sub

    ' summary
    ' Entry point to run the form.

        Public Shared Sub Main()
            Application.EnableVisualStyles()
            Application.SetCompatibleTextRenderingDefault(False)
        Application.Run(New Form1())   '(New ColumnChartExample())
    End Sub

    End Class

Hope you are able to shed some light on my mistake?

Regards,
Antony

[.paul.]

What happens if you highlight the word Chart in your code window? Are you offered an intellisense drop-down? You’ll often find the drop-down offers the solution to your problem

[AntonyL]

Hi Paul,

Intellisense just changes Dim to Private but does not clear the error.

I can use Dim chart as new Label , for example.
or if I switch back to VB6 or VS2012, it works. I am referencing .Net 4.8
I am using VS2026 and I cannot find any workable solution.
The Microsoft references are of no use and refer to System.Windows.Forms.DataVisualization.Charting
When I search Keywords, there is no reference to Chart yet I can use the Chart object from the toolbox
If I have to add a NuGet package to add this functionality, is there one that you might recommend?
I am only trying to create a simple XY graph with X as time and Y with Blue positive bar going above Zero and Red negative bar values going below Zero

[.paul.]

You need a reference to System.Windows.Forms.DataVisualization. Check you have that first...

[.paul.]

Hi Paul,

Intellisense just changes Dim to Private but does not clear the error.

I can use Dim chart as new Label , for example.
or if I switch back to VB6 or VS2012, it works. I am referencing .Net 4.8
I am using VS2026 and I cannot find any workable solution.
The Microsoft references are of no use and refer to System.Windows.Forms.DataVisualization.Charting
When I search Keywords, there is no reference to Chart yet I can use the Chart object from the toolbox
If I have to add a NuGet package to add this functionality, is there one that you might recommend?
I am only trying to create a simple XY graph with X as time and Y with Blue positive bar going above Zero and Red negative bar values going below Zero

You appear to be selecting the variable name ‘chart’. I meant to select the type name ‘Chart’. You should be offered options such as qualifying the type name ‘Chart’ as ‘Charting.Chart’ among other solutions…

[AntonyL]

Hi Paul,

After much fiddling around, I finally came up with a workable solution to my problem

It seems that I needed to provide the fully resolved object name as in the line below.
Dim chart As New DataVisualization.Charting.Chart

I had already included
Imports System.Windows.Forms.DataVisualization.Charting
but this had no impact on being able to use Chart in
Dim chart As New Chart

So the working code is

Imports System.Security.Cryptography.X509Certificates
Imports System.Windows.Forms.DataVisualization.Charting


Public Class Form1 'ColumnChartExample
    ' <summary>
    ' Windows Forms example for a column chart with time (seconds) on the X-axis
    ' and positive/negative values on the Y-axis.
    ' Positive values are displayed in blue; negative values are displayed in red.
    ' </summary>

    Inherits Form

    Dim chart As New DataVisualization.Charting.Chart
    Private chartArea As ChartArea
    Private series As Series

    Public info(10) As Integer
    Private Sub Form_Load()

    End Sub
    Private Sub Data()
        info = {1, 3, 4, 3, 2, 1, 0, -1, -3, -4}
    End Sub

    Public Sub New()
        ' Initialize the form
        Me.Text = "Column Chart Example"
        Me.Size = New Drawing.Size(900, 600)

        ' Create the chart control
        chart = New DataVisualization.Charting.Chart
        chart.Dock = DockStyle.Fill

        ' Create and configure the chart area
        chartArea = New ChartArea("MainArea")
        chartArea.AxisX.Title = "Time (seconds)"
        chartArea.AxisY.Title = "Value"

        ' Add a zero-crossing line on the Y-axis for clarity
        chartArea.AxisX.Crossing = 0
        chartArea.AxisY.Crossing = 0
        chartArea.AxisY.IntervalAutoMode = IntervalAutoMode.VariableCount

        ' Optional: customize grid lines
        chartArea.AxisX.MajorGrid.LineColor = Drawing.Color.LightGray
        chartArea.AxisY.MajorGrid.LineColor = Drawing.Color.LightGray

        chart.ChartAreas.Add(chartArea)

        ' Create and configure the data series
        series = New Series("DataSeries")
        series.ChartType = SeriesChartType.Column
        series.ChartArea = "MainArea"
        series.IsValueShownAsLabel = True
        series.LabelForeColor = Drawing.Color.Black

        ' Sample data: time in seconds and corresponding positive/negative values
        Dim data As New List(Of Tuple(Of Double, Double)) From {
            Tuple.Create(1.0, 15.0),
            Tuple.Create(2.0, -8.0),
            Tuple.Create(3.0, 22.0),
            Tuple.Create(4.0, -5.0),
            Tuple.Create(5.0, -18.0),
            Tuple.Create(6.0, 7.0),
            Tuple.Create(7.0, 0.0),
            Tuple.Create(8.0, -12.0),
            Tuple.Create(9.0, 30.0),
            Tuple.Create(10.0, -3.0)
        }

        ' Populate the series and color each column based on positive/negative value
        For Each point In data
            Dim dp As New DataPoint()
            dp.SetValueXY(point.Item1, point.Item2)
            dp.AxisLabel = point.Item1.ToString() ' X-axis label shows time in seconds

            ' Color logic: blue for positive, red for negative
            If point.Item2 >= 0 Then
                dp.Color = Drawing.Color.Blue
            Else
                dp.Color = Drawing.Color.Red
            End If

            series.Points.Add(dp)
        Next

        chart.Series.Add(series)

        ' Add a legend for clarity
        Dim legend As New Legend("MainLegend")
        legend.Docking = Docking.Top
        chart.Legends.Add(legend)

        ' Add the chart to the form
        Me.Controls.Add(chart)
    End Sub

    ''' <summary>
    ''' Entry point to run the form.
    ''' </summary>
    <STAThread()>
        Public Shared Sub Main()
            Application.EnableVisualStyles()
            Application.SetCompatibleTextRenderingDefault(False)
        Application.Run(New Form1())   '(New ColumnChartExample())
    End Sub

    End Class

Regards,
Antony