Bind Radgrid on linkbutton and not pageload

[Kevin]

what I ahve is several drop downs at the top of my page and a linkbutton.  Once they pick what they want and then pick the link button it should fire the radgrid to load.  What I am finding out though is the radgrid wants to load on page load and it is erroring out everytime becuase it does not have the ids from the dropdownlists, how can I avoid this.  Originally I put in a fillGrid private sub  but then I loast fucntionality of paging and the grid woould never show with the editing fucntionality I have built in.

<telerik:RadGrid ID="myRadGrid" runat="server" Width="75%" BorderWidth="1px" CellPadding="6" GridLines="None" BorderColor="#404040" Skin="Web20">
                       <ExportSettings ExportOnlyData="true" FileName="DonorSlots" IgnorePaging="true" OpenInNewWindow="true"></ExportSettings>
                       <MasterTableView AutoGenerateColumns="false" DataKeyNames="intDeployId" Name="MasterGrid" BorderColor="#404040" Font-Size="9" Font-Names="Veranda,arial,sans-serif" AllowPaging="True"
                       PageSize="20" PagerStyle-Mode="NumericPages" HeaderStyle-HorizontalAlign="Center" GridLines="Both" BorderWidth="1px" CommandItemDisplay="Top" EditMode="EditForms">
                       <CommandItemSettings ShowAddNewRecordButton="false" ShowRefreshButton="false" ShowExportToExcelButton="false" /><AlternatingItemStyle BackColor="#B0C4DE"  HorizontalAlign="Center" />
                       <ItemStyle HorizontalAlign="Center" /><HeaderStyle ForeColor="White" Font-Bold="true" BorderColor="#404040" BorderWidth="1px" />
                           <CommandItemTemplate>
                               <table width="100%">
                                   <tr>
                                       <td align="right"><asp:Button ID="btnExport" runat="server" CommandName="ExportToExcel" Text="Export Excel" /></td>
                                   </tr>
                               </table>
                           </CommandItemTemplate>
                           <Columns>
                               <telerik:GridEditCommandColumn UniqueName="EditCommandColumn" EditText="Update"></telerik:GridEditCommandColumn>
                               <telerik:GridTemplateColumn HeaderText="HIST">
                                   <ItemTemplate>
                                           <asp:Image ID="imgLooker" runat="server" ImageUrl="~/Images/ViewResources.gif" ImageAlign="Middle" BorderStyle="None" />
                                           <asp:PopupControlExtender ID="popInfo" runat="server" PopupControlID="pnlPop" TargetControlID="imgLooker" DynamicContextKey='<% #Eval("strSSN") %>'
                                           DynamicControlID="pnlpop" DynamicServiceMethod="HelloWorld" Position="bottom"></asp:PopupControlExtender>
                                   </ItemTemplate>
                               </telerik:GridTemplateColumn>
                               <telerik:GridBoundColumn DataField="strFullname" HeaderText="NAME" />
                               <telerik:GridBoundColumn DataField="strPrevUic" HeaderText="PRIOR UIC" />
                               <telerik:GridBoundColumn DataField="strPara" HeaderText="PARA" />
                               <telerik:GridBoundColumn DataField="strLine" HeaderText="LINE" />
                               <telerik:GridBoundColumn DataField="strGrade" HeaderText="GRADE" />
                           </Columns>
                           <EditFormSettings EditFormType="Template">
                               <FormTemplate>
                                       <table width="100%">
                                       <tr>
                                           <td style="width:50%" align="right">Prior Uic: </td>
                                           <td style="width:50%" align="left"><asp:TextBox ID="txtPriorUic" runat="server" Width="100px" Text='<%# Bind("strPrevUic") %>'></asp:TextBox></td>
                                       </tr>
                                       <tr>
                                           <td style="height:5px"></td>
                                       </tr>
                                       <tr>
                                           <td style="width:50%" align="right">Para: </td>
                                           <td style="width:50%" align="left""><asp:TextBox ID="txtpara" runat="server" Width="100px" Text='<%# Bind("strPara") %>'></asp:TextBox></td>
                                       </tr>
                                       <tr>
                                           <td style="height:5px"></td>
                                       </tr>
                                       <tr>
                                           <td style="width:50%" align="right"> Line: </td>
                                           <td style="width:50%" align="left"><asp:TextBox ID="txtLine" runat="server" Width="100px" Text='<%# Bind("strLine") %>'></asp:TextBox></td>
                                       </tr>
                                       <tr>
                                           <td style="height:5px"></td>
                                       </tr>
                                       <tr>
                                           <td style="width:50%" align="right">Return Grade: </td>
                                           <td style="width:50%" align="left"><asp:DropDownList ID="ddlRank" runat="server" CausesValidation="false" Width="105px">
                                                   <asp:ListItem Value="0">Pick Grade</asp:ListItem>
                                                   <asp:ListItem Value="E4">E4 Below</asp:ListItem>
                                                   <asp:ListItem Value="E5">E5</asp:ListItem>
                                                   <asp:ListItem Value="E6">E6</asp:ListItem>
                                                   <asp:ListItem Value="E7">E7</asp:ListItem>
                                                   <asp:ListItem Value="E8">E8</asp:ListItem>
                                                   <asp:ListItem Value="E9">E9</asp:ListItem>
                                                   <asp:ListItem Value="W1">W1</asp:ListItem>
                                                   <asp:ListItem Value="W2">W2</asp:ListItem>
                                                   <asp:ListItem Value="W3">W3</asp:ListItem>
                                                   <asp:ListItem Value="W4">W4</asp:ListItem>
                                                   <asp:ListItem Value="W5">W5</asp:ListItem>
                                                   <asp:ListItem Value="O2">O2 Below</asp:ListItem>
                                                   <asp:ListItem Value="O3">O3</asp:ListItem>
                                                   <asp:ListItem Value="O4">O4</asp:ListItem>
                                                   <asp:ListItem Value="O5">O5</asp:ListItem>
                                                   <asp:ListItem Value="O6">06</asp:ListItem>
                                                   <asp:ListItem Value="O7">O7</asp:ListItem>
                                                   <asp:ListItem Value="O8">08</asp:ListItem>
                                               </asp:DropDownList>
                                           </td>
                                       </tr>
                                   </table>
                                   <table width="100%">
                                           <tr>
                                               <td style="width:50%" align="right"></td>
                                               <td style="width:50%" align="left">
                                               <asp:LinkButton ID="lnkSubmit" runat="server" text='<%# IIf((TypeOf(Container) is GridEditFormInsertItem), "Insert", "Update") %>'
                                               CommandName='<%# IIf((TypeOf(Container) is GridEditFormInsertItem), "PerformInsert", "Update")%>'></asp:LinkButton>

                                               <asp:LinkButton ID="lnkCancel" runat="server" CausesValidation="false" CommandName="Cancel" Text="Cancel"></asp:LinkButton>
                                           </td>
                                       </tr>
                                   </table>
                               </FormTemplate>
                           </EditFormSettings>
                       </MasterTableView>
                   </telerik:RadGrid>

Protected Sub myRadGrid_NeedDataSource(sender As Object, e As Telerik.Web.UI.GridNeedDataSourceEventArgs) Handles myRadGrid.NeedDataSource
       Dim DeployId As String = Convert.ToInt16(ddlDeployment.SelectedValue.ToString())
       Dim Bn As String = ddlBn.SelectedValue
       Dim Uic As String = ddlUic.SelectedValue
       Dim SqlWhere As String = ""
       If CInt(DeployId) > 0 And Bn = "0" And ddlUic.SelectedValue = "" Then
           SqlWhere = "mu.intMobilizationId = " & ddlDeployment.SelectedValue & " "
       ElseIf CInt(DeployId) > 0 And ddlBn.SelectedValue > "" And ddlUic.SelectedValue = "0" Then
           SqlWhere = "mu.intMobilizationId = " & ddlDeployment.SelectedValue & " and mu.strAAUic = '" & ddlBn.SelectedValue & "'"
       ElseIf CInt(DeployId) > 0 And ddlBn.SelectedValue > "0" And ddlUic.SelectedValue > "0" Then
           SqlWhere = "mu.intMobilizationId = " & ddlDeployment.SelectedValue & " and mu.strAAUic = '" & ddlBn.SelectedValue & "' and mu.intUnitMobId = " & ddlUic.SelectedValue & ""
       End If
       sql = "Select up.intDeployId, up.strPrevUic, up.strPara, up.strLine, up.strGrade, mn.strFullname, up.strSSN From tblMobUnitPersonnel as up INNER JOIN tblMobUnitPosition as p on p.intPositionID = up.intPositionId " _
           & "INNER JOIN tblMOBUnits mu on mu.intUnitMobId = p.intUnitMobID INNER JOIN MnNgPersonnel.dbo.tblMNNatPersonnel mn on mn.strSSN = up.strSSN WHERE " & SqlWhere & " Order by up.strPrevUic, up.strPara, up.strLine"
       myRadGrid.DataSource = getData(sql)
   End Sub

[Princy]

Hi Kevin,

I guess you want to bind the RadGrid using NeedDataSource event on a LinkButton Click. Please take a look into the following code snippet.

VB:

Private Bind As Boolean = False
Public Shared connection As String = WebConfigurationManager.ConnectionStrings("NorthwindConnectionString3").ConnectionString
Private conn As New SqlConnection(connection)
Public SqlCommand As New SqlCommand()
Protected Sub myRadGrid_NeedDataSource(sender As Object, e As Telerik.Web.UI.GridNeedDataSourceEventArgs)
    If Bind Then
        Dim selectQuery1 As String = "select top 10 * from Orders"
        Dim adapter1 As New SqlDataAdapter(selectQuery1, conn)
        Dim dt1 As New DataTable()
        conn.Open()
        adapter1.Fill(dt1)
        conn.Close()
        myRadGrid.DataSource = dt1
    End If

End Sub
'Binding the RadGrid on LinkButton Click
Protected Sub LinkButton1_Click(sender As Object, e As EventArgs)
    Bind = True
    myRadGrid.Rebind()
End Sub

Hope this helps.
Thanks,
Princy.

[Kevin]

Hi,
yes this is what I want but the problem is that the radgird seems to want to load on page load even through I am not calling it on page load, it tries to load the radgrid and runs into my dropdownlists that have not been picked and errors out.  To resolve temporarily I placed inside update panels, so it needs a trigger to load it, but this was a temp solution to the problem of the radgrid automatically loading on page load, when it needs to only load on the click button event.

<tr>
                       <td align="center" width="100%">
                           <asp:DropDownList id="ddlDeployment" Runat="server" Width="160" AutoPostBack="True"></asp:DropDownList>
                           <asp:DropDownList id="ddlBn" Runat="server" Width="120" AutoPostBack="True"></asp:DropDownList>
                           <asp:DropDownList id="ddlUic" Runat="server" Width="120" AutoPostBack="true"></asp:DropDownList>
                       </td>
                   </tr>

Protected Sub myRadGrid_NeedDataSource(sender As Object, e As Telerik.Web.UI.GridNeedDataSourceEventArgs) Handles myRadGrid.NeedDataSource
        Dim DeployId As String = Convert.ToInt16(ddlDeployment.SelectedValue.ToString())
        Dim Bn As String = ddlBn.SelectedValue
        Dim Uic As String = ddlUic.SelectedValue
        Dim SqlWhere As String = " "

        If CInt(DeployId) > 0 And Bn = "0" And ddlUic.SelectedValue = "" Then
            SqlWhere = "mu.intMobilizationId = " & ddlDeployment.SelectedValue & " "
        ElseIf CInt(DeployId) > 0 And ddlBn.SelectedValue > "" And ddlUic.SelectedValue = "0" Then
            SqlWhere = "mu.intMobilizationId = " & ddlDeployment.SelectedValue & " and mu.strAAUic = '" & ddlBn.SelectedValue & "'"
        ElseIf CInt(DeployId) > 0 And ddlBn.SelectedValue > "0" And ddlUic.SelectedValue > "0" Then
            SqlWhere = "mu.intMobilizationId = " & ddlDeployment.SelectedValue & " and mu.strAAUic = '" & ddlBn.SelectedValue & "' and mu.intUnitMobId = " & ddlUic.SelectedValue & ""
        End If

        If CInt(DeployId) = 0 Then
            myRadGrid.DataSource = Nothing
        Else
            sql = "Select up.intDeployId, up.strPrevUic, up.strPara, up.strLine, up.strGrade, mn.strFullname, up.strSSN From tblMobUnitPersonnel as up INNER JOIN tblMobUnitPosition as p on p.intPositionID = up.intPositionId " _
          & "INNER JOIN tblMOBUnits mu on mu.intUnitMobId = p.intUnitMobID INNER JOIN MnNgPersonnel.dbo.tblMNNatPersonnel mn on mn.strSSN = up.strSSN WHERE " & SqlWhere & " Order by up.strPrevUic, up.strPara, up.strLine"

            myRadGrid.DataSource = getData(sql)
        End If
    End Sub

Protected Sub Page_Load(sender As Object, e As System.EventArgs) Handles Me.Load
       If Not IsPostBack Then
           'Set the Page label
           Dim page As Label = CType(Master.FindControl("lblPage"), Label)
           page.Text = "Readiness Tracker - Manage Donor Slots"
           'check for admin rights
           If checkAdmin() = False Then
               Response.Redirect("~/ErrorPage/NoAccess.aspx")
           Else
               'Fill Deployment menu system
               sql = "Select intMobilizationId, strDeployment from tblMobDeployment where bitArchive is Null order by strDeployment"
               ddlDeployment.Items.Add(New ListItem("Pick Deployment", "0"))
               buildDD(sql, ddlDeployment)
           End If
       End If
   End Sub

[Kevin]

Hi,
Ok I have another case of the same problem, my Radgrid is trying to load on page load, but I needs an Id of a radibuttonlist before it can load.  it errors out on page load and says my datakeys is not there and that's correct because it should not even try to load at this point as I have not even picked the radio button value.  How can I get around this.

<asp:Content ID="Content2" ContentPlaceHolderID="MainContent" Runat="Server">
     <asp:Panel ID="pnlGrid" runat="server">
        <table width="100%">
            <tr>
                <td style="height:10px"></td>
            </tr>
            <tr>
                <td align="center">
                    <asp:RadioButtonlist ID="rblView" runat="server" RepeatDirection="Horizontal" TextAlign="Right" RepeatLayout="Flow" Visible="false">
                        <asp:ListItem Value="1" Text="Pending Issues    "></asp:ListItem>
                        <asp:ListItem Value="2" Text="Pending ReIssues    "></asp:ListItem>
                        <asp:ListItem Value="3" Text="Pending Transfers    "></asp:ListItem>
                    </asp:RadioButtonlist>
                </td>
            </tr>
            <tr>
                <td align="center">
                    <telerik:RadGrid ID="myRadGrid" runat="server" Width="98%" BorderWidth="1px" CellPadding="6" GridLines="None" BorderColor="#404040" Skin="Web20">
                    <MasterTableView AutoGenerateColumns="false" DataKeyNames="intRecId" Name="MasterGrid" BorderColor="#404040" Font-Size="9" Font-Names="Veranda,arial,sans-serif" HeaderStyle-HorizontalAlign="Center"
                    GridLines="Both" BorderWidth="1px" AllowPaging="true" PageSize="20" PagerStyle-Mode="NumericPages"><ItemStyle HorizontalAlign="Center"/>
                    <AlternatingItemStyle BackColor="#B0C4DE"  HorizontalAlign="Center" /><HeaderStyle ForeColor="White" Font-Bold="true" BorderColor="#404040" BorderWidth="1px" />
                       <Columns>
                            <telerik:GridBoundColumn DataField="strSN" HeaderText="SN" />
                            <telerik:GridBoundColumn DataField="ITEM" HeaderText="EQUIPMENT" />
                            <telerik:GridBoundColumn DataField="NAME" HeaderText="NAME" />
                            <telerik:GridBoundColumn DataField="dtIssued" HeaderText="DT_ISSUED" />
                            <telerik:GridBoundColumn DataField="intLocationId"  HeaderText="UNIT" />
                            <telerik:GridBoundColumn DataField="strIMOGroup" HeaderText="IMO" />
                        </Columns>
                    </MasterTableView>
                    </telerik:RadGrid>
                </td>
            </tr>
        </table>
    </asp:Panel>
</asp:Content>

Protected Sub Page_Load(sender As Object, e As System.EventArgs) Handles Me.Load
        If Not IsPostBack Then
            rblView.Visible = True
        End If
    End Sub

    Protected Sub myRadGrid_NeedDataSource(sender As Object, e As Telerik.Web.UI.GridNeedDataSourceEventArgs) Handles myRadGrid.NeedDataSource
        Dim rbl As String = rblView.SelectedValue

        Select Case rbl
            Case 1
                sql = "Select dr.intRecId, dr.strSN, mm.strManufacturer + ' ' + m.strMake + ' ' + dm.strModel ITEM, mn.strRank + ' ' + strFullname Name, Convert(varchar(10), dtIssued, 111) dtIssued, intLocationId, " _
                & "strIMOGroup From drat_Received dr INNER JOIN Drat_Model dm on dm.intModelId = dr.intModelid INNER JOIN Drat_Make m on m.intMakeId = dm.intMakeId INNER JOIN Drat_Manufacturer mm on mm.intManufacturerId = " _
                & "m.intManufacturerId INNER JOIN Drat_Issued i on i.intRecId = dr.intRecId INNER JOIN MNNgpersonnel.dbo.tblMnNatPersonnel mn on mn.intPersonnelid = i.intIssuedTo Where dtSigned Is NULL"
            Case 2
            Case 3

        End Select

        myRadGrid.DataSource = getData(sql)
    End Sub

[Princy]

Hi Kevin,

One suggestion is to make the RadGrid Visibility to false in the Aspx page and make it visible in the LinkButton Click event. Please take a look into the following code snippet.

ASPX:

<telerik:RadGrid ID="myRadGrid" runat="server" Width="75%" BorderWidth="1px"
            CellPadding="6" GridLines="None" BorderColor="#404040" Skin="Web20"
            onneeddatasource="myRadGrid_NeedDataSource" Visible="false"></telerik:RadGrid>

VB:

Protected Sub Page_Load(sender As Object, e As EventArgs)
    If Not IsPostBack Then
        rblView.Visible = True
    End If
End Sub
Protected Sub myRadGrid_NeedDataSource(sender As Object, e As Telerik.Web.UI.GridNeedDataSourceEventArgs)

    If Bind Then
     'your code
    End If

End Sub
Protected Sub LinkButton1_Click(sender As Object, e As EventArgs)
    Bind = True
    myRadGrid.Visible = True
    myRadGrid.Rebind()
End Sub

Thanks,
Princy.

[Ricardo]

what is purpose of NeedDataSource if it tries to load the grid on PageLoad???

[Princy]

Hi Ricardo,

The advanced data binding of a RadGrid control is handling the NeedDataSource event. RadGrid fires the NeedDataSource event each time it needs to be bound to a data source. You can take a look at the following articles to have more information about when this event fires:
Advanced Data-binding (Using NeedDataSource Event)
Event sequence

Thanks,
Princy

[Suresh]

Hello All and Telerik Admin,
I have tried one trick that is... I added an "if condition" of Page.IsPostback
If page is postback, I let the "OnNeedDataSource" code run else nothing.. And it seems working...

Could you please confirm if this approach is good to go with?

[Suresh]

Hello All and Telerik Admin,
I have tried one trick that is... I added an "if condition" of Page.IsPostback
If page is postback, I let the "OnNeedDataSource" code run else nothing.. And it seems working...

Could you please confirm if this approach is good to go with?