Hi,
I'm trying to present results on an aspx web page where a store procedure parameter is defined by a dropdown list control on the page.
To help accomplish this, I have followed this guide from Microsoft and have my resultset presented in a DataGrid view. But I cannot seem to adapt it to present the resultset in a chart.
As you can see from my VB code below, I thought it would simply be a case of adapting the GridView databind to a Chart. I have tried various other options, and have successfully generated my data in a chart using a hard-coded parameter in an SQL statement on the ASP page. But when it comes to using the control, I get an empty chart.
Below is what I have so far. Any help greatly appreciated.
Imports System.Data.SqlClient
Public Class Report
Inherits System.Web.UI.Page
Protected MIUDropDownList As System.Web.UI.WebControls.DropDownList
Protected ResultChart As DataVisualization.Charting.Chart
Dim objConn As SqlConnection
Dim objCmd As SqlCommand
Dim dataReader As SqlDataReader
Dim strSql As String
Private Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
If Not IsPostBack Then
Dim objConn As SqlConnection
Dim dataReader As SqlDataReader
objConn = New SqlConnection("ConnectionString")
strSql = "EXEC usp_GetRadioUnitSerialNumber"
objCmd = New SqlCommand(strSql, objConn)
Try
objConn.Open()
dataReader = objCmd.ExecuteReader
With MIUDropDownList
.DataSource = dataReader
.DataTextField = "RadioUnitSerialNumber"
.DataValueField = "RadioUnitSerialNumber"
.DataBind()
End With
Catch ex As Exception
Finally
objConn.Close()
objConn.Dispose()
End Try
End If
End Sub
Protected Sub ButtonGetRadioUnit_Click(ByVal sender As Object, ByVal e As EventArgs) Handles ButtonGetRadioUnit.Click
objConn = New SqlConnection("ConnectionString")
strSql = "usp_RadioUnitReadingHistory '" & MIUDropDownList.SelectedItem.Value & "'"
objCmd = New SqlCommand(strSql, objConn)
Try
objConn.Open()
dataReader = objCmd.ExecuteReader()
'Bind to Grid
GridView1.DataSource = dataReader
GridView1.DataBind()
''Bind to Chart
'ResultChart.DataSource = dataReader
'ResultChart.DataBind()
Catch ex As Exception
Finally
objConn.Close()
objConn.Dispose()
End Try
End Sub
End ClassASPX page
<asp:Content ID="Content2" ContentPlaceHolderID="MainContent" runat="server">
<asp:DropDownList ID="MIUDropDownList" runat="server" DataTextField="RadioUnitSerialNumber">
</asp:DropDownList>
<asp:Button ID="ButtonGetRadioUnit" runat="server" Font-Size="8pt" Height="20px" Text="Select MIU" Width="60px" OnClick="ButtonGetRadioUnit_Click" />
<br />
<asp:Chart ID="ResultChart" runat="server" Height="500px" Width="800px" >
<Series>
<asp:Series ChartType="Line" Name="Series1" XValueMember="DateTimeStamp" YValueMembers="Value">
</asp:Series>
</Series>
<ChartAreas>
<asp:ChartArea Name="ChartArea1">
</asp:ChartArea>
</ChartAreas>
</asp:Chart>
<asp:GridView ID="GridView1" runat="server">
</asp:GridView>
</asp:Content>