Hi there,

I having a bit (understatement) of a problem here with datagrids. If a record is deleted or amended the new values are not diplayed. However, if i click the refresh button on the browser, the new values are displayed. Im rebinding the data each time the database is modified, so I cant understand why the updates are not being displayed until the page is reloaded.

Any ideas? Heres the code I'm using.


    Private Sub Page_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        If Not Page.IsPostBack Then
            GetPersonalInfo()
            BindDataVehicleInfo()
        End If
    End Sub


    Sub BindDataVehicleInfo()
        Dim intCustNo As Integer = Request.Cookies("GCSCommerce_CustNo").Value
        Dim strConn As String = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" & Server.MapPath("\GCSwebsite.mdb") & ";"
        Dim MySQL As String = "SELECT RegNo, Make, Model, CarYear, EngineSize, FuelType FROM Vehicles " & _
        "WHERE (((CustNo)=" & intCustNo & "));"
        Dim MyConn As New OleDbConnection(strConn)
        Dim objDR As OleDbDataReader
        Dim Cmd As New OleDbCommand(MySQL, MyConn)

        MyConn.Open()
        objDR = Cmd.ExecuteReader(System.Data.CommandBehavior.Clos eConnection)

        If Not objDR.Read() Then
            objDR.Close()
            MyConn.Open()
            Cmd.ExecuteNonQuery()
            lblNoVehicles.Text = "There are no vehicles associated with you account. Please add your vehicle details by clicking"
            HyperLink1.Visible = True
            HyperLink2.Visible = False
            dgVehicleInfo.Visible = False
        Else
            objDR.Close()
            MyConn.Open()
            'Set the datagrid's datasource to the datareader and databind
            dgVehicleInfo.DataSource = Cmd.ExecuteReader(CommandBehavior.CloseConnection)
            dgVehicleInfo.DataBind()
        End If
    End Sub

    Sub dgVehicleInfo_Edit(ByVal sender As Object, ByVal e As DataGridCommandEventArgs)
        dgVehicleInfo.EditItemIndex = e.Item.ItemIndex
        BindDataVehicleInfo() 'Rebuild datagrid to display new info
    End Sub

    Sub dgVehicleInfo_Cancel(ByVal sender As Object, ByVal e As DataGridCommandEventArgs)
        dgVehicleInfo.EditItemIndex = -1
        BindDataVehicleInfo()
    End Sub

    Sub dgVehicleInfo_Update(ByVal sender As Object, ByVal e As DataGridCommandEventArgs)
        'Read in the values of the updated row
        Dim strRegNo As String = dgVehicleInfo.DataKeys(e.Item.ItemIndex)
        Dim strMake As String = CType(e.Item.FindControl("txtMake"), TextBox).Text
        Dim strModel As String = CType(e.Item.FindControl("txtModel"), TextBox).Text
        Dim strCarYear As String = CType(e.Item.FindControl("txtCarYear"), TextBox).Text
        Dim strEngineSize As String = CType(e.Item.FindControl("txtEngineSize"), TextBox).Text
        Dim strFuelType As String = CType(e.Item.FindControl("lstFuelTypes"), DropDownList).SelectedItem.Value

        Dim strConn As String = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" & Server.MapPath("\GCSwebsite.mdb") & ";"
        Dim MySQL As String = "UPDATE Vehicles SET Vehicles.Make = '" & strMake & "', Model = '" & strModel & "', CarYear = '" & strCarYear & "', EngineSize = '" & strEngineSize & "', FuelType = '" & strFuelType & "' WHERE RegNo = '" & strRegNo & "'"
        Dim MyConn As New OleDbConnection(strConn)
        Dim objDR As OleDbDataReader
        Dim Cmd As New OleDbCommand(MySQL, MyConn)

        MyConn.Open()
        objDR = Cmd.ExecuteReader(System.Data.CommandBehavior.Clos eConnection)
        'Finally, set the EditItemIndex to -1 and rebind the DataGrid
        dgVehicleInfo.EditItemIndex = -1
        BindDataVehicleInfo()
    End Sub

    Sub dgVehicleInfo_Delete(ByVal sender As Object, ByVal e As DataGridCommandEventArgs)
        'Get the RegNo of the row whose Delete button was clicked
        Dim SelectedRegNo As String = dgVehicleInfo.DataKeys(e.Item.ItemIndex)

        Dim strConn As String = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" & Server.MapPath("\GCSwebsite.mdb") & ";"
        Dim MySQL As String = "DELETE Vehicles.* FROM Vehicles WHERE RegNo = '" & SelectedRegNo & "'"
        Dim MyConn As New OleDbConnection(strConn)
        Dim objDR As OleDbDataReader
        Dim Cmd As New OleDbCommand(MySQL, MyConn)
        MyConn.Open()
        objDR = Cmd.ExecuteReader(System.Data.CommandBehavior.Clos eConnection)
        'Finally, set the EditItemIndex to -1 and rebind the DataGrid
        dgVehicleInfo.EditItemIndex = -1
        BindDataVehicleInfo()
    End Sub

    Sub dgVehicles_ItemDataBound(ByVal sender As Object, ByVal e As DataGridItemEventArgs)
        ' First, make sure we're NOT dealing with a Header or Footer row
        If e.Item.ItemType <> ListItemType.Header And e.Item.ItemType <> ListItemType.Footer Then
            'Now, reference the LinkButton control that the Delete ButtonColumn
            'has been rendered to
            Dim btnDelete As Button = CType(e.Item.Cells(0).FindControl("btnDelete"), Button)
            btnDelete.Attributes.Add("onclick", "return confirm_delete();")
        End If
    End Sub



Cheers!

Do you have output caching declared for this web page?

Hi,

No I havent declared output caching. To be honest I'm not too sure how to use it. It looked up a few things on caching and added the following line to my code:

<%@ OutputCache Duration="60" VaryByParam="none" %>

When I done this, the update and cancel buttons on the datagrid did not respond.

Is the line above what you were suggesting? Do I need to specify something for the 'VaryByParam'?

Thanks
Daryl

Output caching would most certainly affect the proper operation of a page.
With that statement you are telling ASP.net to not even RUN that page the next time it's requested. It just takes the cached HTML that the page generates the first time it's run and responds with that instead of processing the page.

Ahh I see. I followed a great article available from: http://aspnet.4guysfromrolla.com/articles/040502-1.aspx when creating my datagrids. I think I followed everything that was mention throughout the article, so I cannot understand this problem at all. Have you any suggetions?

Can anyone help me out?

Im begging!

Did you ever turn off the line you said is in there?

<%@ OutputCache Duration="60" VaryByParam="none" %>

This would definately cause problems.

I have skimming the code you first posted, and it looks fine. After you make DB changes (update, delete) you are rebinding the grid. Short of that, I can't imagine what else you need to do.

Hi planoie,

Yeah I took that out. I only tried it because bmainssuggested it. Yeah I cant work it out either. Its not only on this page that the problem occurs. It is happening on every page that modifies the datagrid.

Thanks for replying
Daryl

Hey,

I didn't suggest adding output caching, I was wondering if you had it turned on.

Sorry for any inconvenience.

Brian

Hi,

There has been slight progess. If i remove Sub BindDataVehicleInfo() and put it's contents inside the Page_Load event - use dgVehicleInfo.DataBind() where Sub BindDataVehicleInfo()was previously referenced, when an item is deleted, the effect is displayed immediately. It does delete all the records however.