dear all:

      i meet an an err: System.NullReferenceException:Objec reference not set to an instance of an object when

show a child form with dockingpanel and commandbar control in a mdi form.

 

Public Class Form1

    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        Dim Control, CtlProject As XtremeCommandBars.CommandBarControl

        CtlProject = wndAxCommandBars.ActiveMenuBar.Controls.Add(XtremeCommandBars.XTPControlType.xtpControlPopup, 100, "New", -1, False)
        With CtlProject.CommandBar.Controls
            Control = .Add(XtremeCommandBars.XTPControlType.xtpControlButton, 200, "Exit")
            Control.BeginGroup = True
            Control = .Add(XtremeCommandBars.XTPControlType.xtpControlButton, 300, "Login")
            Control.BeginGroup = True
        End With

        wndAxDockingPane.SetCommandBars(wndAxCommandBars.GetDispatch)
        wndAxDockingPane.Options.HideClient = True
        Dim panA, panB As XtremeDockingPane.Pane
        panA = wndAxDockingPane.CreatePane(1, 220, 1200, XtremeDockingPane.DockingDirection.DockLeftOf, Nothing) '
        panA.title = "This pane1"

        panB = wndAxDockingPane.CreatePane(2, 220, 1200, XtremeDockingPane.DockingDirection.DockBottomOf, panA) '
        panB.title = "This pane1"

    End Sub

    Private Sub wndAxDockingPane_AttachPaneEvent(ByVal sender As System.Object, ByVal e As AxXtremeDockingPane._DDockingPaneEvents_AttachPaneEvent) Handles wndAxDockingPane.AttachPaneEvent
        Select Case e.item.Id
            Case 1 : e.item.Handle = RichTextBox1.Handle.ToInt32
            Case 2 : e.item.Handle = RichTextBox2.Handle.ToInt32
        End Select
    End Sub
End Class

      step5: code in MDIParent1 is follows:

Imports System.Windows.Forms

Public Class MDIParent1

    Private Sub ShowNewForm(ByVal sender As Object, ByVal e As EventArgs) Handles NewToolStripMenuItem.Click, NewToolStripButton.Click
        Dim ChildForm As New Form1
        ChildForm.MdiParent = Me

        Static Dim m_ChildFormNumber As Integer
        m_ChildFormNumber += 1
        ChildForm.Text = "Doc - " & m_ChildFormNumber

        ChildForm.Show()
    End Sub
End Class

      step5: when startwith form1, every thing runs well, includes the commandbar and dockingpanel control

    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        Dim Control, CtlProject As XtremeCommandBars.CommandBarControl

 

        Dim Control, CtlProject As XtremeCommandBars.CommandBarControl

        'CtlProject = wndAxCommandBars.ActiveMenuBar.Controls.Add(XtremeCommandBars.XTPControlType.xtpControlPopup, 100, "New", -1, False)
        'With CtlProject.CommandBar.Controls
        '    Control = .Add(XtremeCommandBars.XTPControlType.xtpControlButton, 200, "Exit")
        '    Control.BeginGroup = True
        '    Control = .Add(XtremeCommandBars.XTPControlType.xtpControlButton, 300, "Login")
        '    Control.BeginGroup = True
        'End With

        wndAxDockingPane.SetCommandBars(wndAxCommandBars.GetDispatch)
        wndAxDockingPane.Options.HideClient = True
        Dim panA, panB As XtremeDockingPane.Pane
        panA = wndAxDockingPane.CreatePane(1, 220, 1200, XtremeDockingPane.DockingDirection.DockLeftOf, Nothing) '
        panA.title = "This pane1"----->System.NullReferenceException:Objec reference not set to an instance of an object

-------------------------------------