ASP.NET dynamic chart

Question

Is it possible to create charts dynamically and add them to an ASP.NET web form?
I am using the following code but it is not creating any chart.

 For i As Integer = 0 To ddlProject.Items.Count - 1  ' For all Chart
            Dim chartAll As Chart = New Chart()
            chartAll.ID = "_chartAll" & i 
            Dim strsql As String = ""
            strsql = "SELECT distinct [CalculatedDate], [WDC], [Amount] FROM [tbl WeeklyLog] " + _
                       " where 1=1     "
            Dim filtersql As String = ""
            filtersql = filtersql & " and ID = " & ddlProject.Items(i).Value & ""

            Dim ds As New SqlDataSource
            ds.SelectCommand = strsql & filtersql          
            ds.ConnectionString = dbconn.ConnectionString
            chartAll.DataSource = ds
            chartAll.DataBind() 
            divChart1.Controls.Add(chartAll)
        Next

Answer 1

Hi @Hema Ramachandran ,
I checked your code and your description, I think you should want the effect of the following example, I added a comment to the code, I hope it can help you understand better.
Double click on webconfig file and database connect. Write the following line of code.

<connectionStrings>    
  <add name="DBCS" connectionString="***"/>    
</connectionStrings>    

Create database table:

CREATE TABLE [dbo].[StudentMarks](    
    [ID] [int] IDENTITY(1,1) NOT NULL,    
    [StudentName] [nvarchar](50) NULL,    
    [TotalMarks] [int] NULL,    
 CONSTRAINT [PK_StudentMarks] PRIMARY KEY CLUSTERED     
(    
    [ID] ASC    
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]    
) ON [PRIMARY]    
    
GO    
CREATE PROCEDURE spGetStudentMarks    
AS    
BEGIN    
SELECT StudentName,TotalMarks from [dbo].[StudentMarks]    
END    

front code

   <div class="container py-4">    
                <h4 class="text-uppercase text-center">Chart Control in asp.net</h4>    
                <div class="form-group">    
                    <label>Select Chart:</label>    
                    <asp:DropDownList ID="ddlChart" AutoPostBack="true" runat="server" CssClass="custom-select col-md-4" OnSelectedIndexChanged="ddlChart_SelectedIndexChanged"></asp:DropDownList>    
                </div>    
                <asp:Chart ID="Chart1" runat="server" Width="450">    
                    <Titles>    
                        <asp:Title Text="Total Marks of Students"></asp:Title>    
                    </Titles>    
                    <Series>    
                        <asp:Series Name="Series1" ChartArea="ChartArea1"></asp:Series>    
                    </Series>    
                    <ChartAreas>    
                        <asp:ChartArea Name="ChartArea1">    
                            <AxisX Title="Student Name"></AxisX>    
                            <AxisY Title="Total Marks"></AxisY>    
                        </asp:ChartArea>    
                    </ChartAreas>    
                </asp:Chart>    
            </div>    

code behind

Imports System.Data.SqlClient  
Imports System.Web.UI.DataVisualization.Charting  
  
Public Class WebForm2  
    Inherits System.Web.UI.Page  
  
    Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load  
        If Not IsPostBack Then  
            GetChartData()  
            GetChartTypes()  
        End If  
    End Sub  
    Private Sub GetChartTypes()  
        For Each chartType As Integer In [Enum].GetValues(GetType(SeriesChartType))  
            Dim li As ListItem = New ListItem([Enum].GetName(GetType(SeriesChartType), chartType), chartType.ToString())  
            ddlChart.Items.Add(li)  
        Next  
    End Sub  
    Private Sub GetChartData()  
        Dim CS As String = ConfigurationManager.ConnectionStrings("DBCS").ConnectionString  
  
        Using con As SqlConnection = New SqlConnection(CS)  
            Dim cmd As SqlCommand = New SqlCommand("spGetStudentMarks", con)  
            cmd.CommandType = CommandType.StoredProcedure  
            con.Open()  
            Dim rdr As SqlDataReader = cmd.ExecuteReader()  
            'Retrieve the Series to which we want to add DataPoints   
            Dim series As Series = Chart1.Series("Series1")  
            'Loop thru each Student record    
            While rdr.Read()  
                'Add X And Y values using AddXY() method    
                series.Points.AddXY(rdr("StudentName").ToString(), rdr("TotalMarks"))  
            End While  
        End Using  
    End Sub  
    Protected Sub ddlChart_SelectedIndexChanged(ByVal sender As Object, ByVal e As EventArgs)  
        'Call Get ChartData() method when the user select a different chart type   
        GetChartData()  
        Me.Chart1.Series("Series1").ChartType = CType([Enum].Parse(GetType(SeriesChartType), ddlChart.SelectedValue), SeriesChartType)  
    End Sub  
End Class  

Best regards,
Lan Huang

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