mtv = grid.get_masterTableView();

dataItems = mtv.get_dataItems();

for (z; z < AllAvailablePipes; z++) {

    dataItem = dataItems[z];

    var item = dataItem.set_selected(true);

    SelectedPipes = SelectedPipes + 1

    if (SelectedPipes == PipesToBeSelected) break

}

Private Sub rgScripts_PreRender(sender As Object, e As EventArgs) Handles rgScripts.PreRender
    If Not IsPostBack Then
        For Each item As GridItem In rgScripts.MasterTableView.Items
            If TypeOf item Is GridEditableItem Then
                Dim editableItem As GridEditableItem = CType(item, GridDataItem)
                editableItem.Edit = True
            End If
        Next
        rgScripts.Rebind()
    End If
End Sub

 private void GenerateTreeView()
    {
        OleDbConnection dbCon = new OleDbConnection("Provider=SQLOLEDB;Data Source=PC-DEV002\\SQLEXPRESS;Persist Security Info=True;Password=dcube2005*;User ID=sa;Initial Catalog=SuiviConso");
        dbCon.Open();
        OleDbDataAdapter adapter = new OleDbDataAdapter("SELECT  su.SiteId, u.userid, u.nomUser, s.NomSite FROM   [User] AS u LEFT OUTER JOIN  Rel_Site_User AS su ON su.UserId = u.UserId LEFT OUTER JOIN Sites AS s ON s.SiteID = su.SiteId WHERE        (su.UserId = 13) ", dbCon);
        DataSet ds = new DataSet();
        adapter.Fill(ds);
        RadTreeView1.DataFieldID = "SiteId";
        RadTreeView1.DataFieldParentID = "UserId";
        RadTreeView1.DataTextField = "nomUser";
        RadTreeView1.DataValueField = "NomSite";
        RadTreeView1.DataSource = ds;
        RadTreeView1.DataBind();
        RadTreeView1.ExpandAllNodes();
    }

 <telerik:RadTreeView ID="RadTreeView1" runat="server" Width="100%" Height="250px">
                <DataBindings>
                    <telerik:RadTreeNodeBinding Expanded="true"></telerik:RadTreeNodeBinding>
                </DataBindings>
            </telerik:RadTreeView>