Hi mukesh1,

You are not adding tooltip for each series. You are assigning tooltip for Chart1.Series["Tasks"]. So its shows in result last value on all row tooltip.

I have modified your code.

Populate ASP.Net 4.0 Chart Control Pie Chart from SQL Server Database

Using the above article i have created example. Check this example. Now please take its reference and correct your code.

HTML

<asp:Chart ID="Chart1" runat="server" Width="932px">
    <Series>
        <asp:Series Name="Tasks" YValuesPerPoint="6" ChartType="Column" CustomProperties="LabelStyle=Top"
            YValueType="Int32" IsValueShownAsLabel="true">
            <EmptyPointStyle IsValueShownAsLabel="false" IsVisibleInLegend="false" />
        </asp:Series>
    </Series>
    <ChartAreas>
        <asp:ChartArea Name="ChartArea1">
        </asp:ChartArea>
    </ChartAreas>
    <Legends>
        <asp:Legend Name="Task point" Alignment="Center" Docking="Right">
        </asp:Legend>
    </Legends>
</asp:Chart>

C#

protected void Page_Load(object sender, EventArgs e)
{
    if (!IsPostBack)
    {
        string query = string.Format("SELECT TOP 20 ShipCity, COUNT(OrderId) FROM Orders GROUP BY ShipCity");
        DataTable dt = GetData(query);
        DataSet ds = new DataSet();
        ds.Tables.Add(dt);
        for (int i = 0; i < ds.Tables[0].Rows.Count; i++)
        {
            string title = ds.Tables[0].Rows[i][0].ToString();
            String totalpoint = (ds.Tables[0].Rows[i][1]).ToString();
            if (totalpoint == "")
            {
                totalpoint = "0";
            }
            Series series = new Series();
            series.XValueMember = dt.Columns[0].ColumnName;
            series.YValueMembers = dt.Columns[1].ColumnName;
            series.ChartType = SeriesChartType.Column;
            series.YValuesPerPoint = 6;
            series.YValueType = ChartValueType.Int32;
            series.IsValueShownAsLabel = true;
            series.LegendText = title;
            Chart1.Series.Add(series);
            Chart1.Series[i].Points.AddXY("Task" + (i + 1) + "" + "(" + ds.Tables[0].Rows[i][1].ToString() + ")", totalpoint);
            Chart1.Series[i].ToolTip = title;
            Chart1.ChartAreas["ChartArea1"].AxisX.MajorGrid.LineWidth = 0;
        }
    }
}

private static DataTable GetData(string query)
{
    DataTable dt = new DataTable();
    SqlCommand cmd = new SqlCommand(query);
    String constr = ConfigurationManager.ConnectionStrings["ConString"].ConnectionString;
    SqlConnection con = new SqlConnection(constr);
    SqlDataAdapter sda = new SqlDataAdapter();
    cmd.CommandType = CommandType.Text;
    cmd.Connection = con;
    sda.SelectCommand = cmd;
    sda.Fill(dt);
    return dt;
}

VB.Net

Protected Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs)
    If Not IsPostBack Then
        Dim query As String = String.Format("SELECT TOP 20 ShipCity, COUNT(OrderId) FROM Orders GROUP BY ShipCity")
        Dim dt As DataTable = GetData(query)
        Dim ds As DataSet = New DataSet()
        ds.Tables.Add(dt)
        For i As Integer = 0 To ds.Tables(0).Rows.Count - 1
            Dim title As String = ds.Tables(0).Rows(i)(0).ToString()
            Dim totalpoint As String =(ds.Tables(0).Rows(i)(1)).ToString()
            If totalpoint = "" Then
                totalpoint = "0"
            End If

            Dim series As Series = New Series()
            series.XValueMember = dt.Columns(0).ColumnName
            series.YValueMembers = dt.Columns(1).ColumnName
            series.ChartType = SeriesChartType.Column
            series.YValuesPerPoint = 6
            series.YValueType = ChartValueType.Int32
            series.IsValueShownAsLabel = True
            series.LegendText = title
            Chart1.Series.Add(series)
            Chart1.Series(i).Points.AddXY("Task" & (i + 1) & "" & "(" + ds.Tables(0).Rows(i)(1).ToString() & ")", totalpoint)
            Chart1.Series(i).ToolTip = title
            Chart1.ChartAreas("ChartArea1").AxisX.MajorGrid.LineWidth = 0
        Next
    End If
End Sub

Private Shared Function GetData(ByVal query As String) As DataTable
    Dim dt As DataTable = New DataTable()
    Dim cmd As SqlCommand = New SqlCommand(query)
    Dim constr As String = ConfigurationManager.ConnectionStrings("ConString").ConnectionString
    Dim con As SqlConnection = New SqlConnection(constr)
    Dim sda As SqlDataAdapter = New SqlDataAdapter()
    cmd.CommandType = CommandType.Text
    cmd.Connection = con
    sda.SelectCommand = cmd
    sda.Fill(dt)
    Return dt
End Function

 Screenshots