使用自动调整图片框/组框vb.net时出错

Question

Hi I am getting an error when I load my program from the exe file but not when I start from visual studio.

The error I receive is

>System.NullReferenceException: Object reference not set to an instance of an object.

at MoveResizeControl.controlHandler.mControl_Resize(Object sender, EventArgs e) in C:\\Users\\AJ\\Documents\\Movable_Re217400212010\\MoveResizeControl\\controlHandler.vb:line 211

at System.Windows.Forms.Control.OnSizeChanged(EventArgs e) at System.Windows.Forms.Control.UpdateBounds(Int32 x, Int32 y, Int32 width, Int32 height, Int32 clientWidth, Int32 clientHeight)

at System.Windows.Forms.Control.UpdateBounds() at System.Windows.Forms.Control.WmWindowPosChanged(Message& m) at System.Windows.Forms.Control.WndProc(Message& m) at System.Windows.Forms.GroupBox.WndProc(Message& m) at System.Windows.Forms.NativeWindow.Callback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam

I know my problem is in this bit of code

    Private Sub Timer7_Tick(sender As Object, e As EventArgs) Handles Timer7.Tick
    Timer2.Start()
    Timer5.Start()
    Dim i As Integer
    i = 0
    Dim bl1 As Integer
    Dim br1 As Integer
    Dim tl1 As Integer
    Dim tr1 As Integer
    Dim bl14 As Integer
    Dim br14 As Integer
    Dim tl14 As Integer
    Dim tr14 As Integer

    bl1 = bl.Text
    br1 = br.Text
    tl1 = tl.Text
    tr1 = tr.Text

    bl14 = bl4.Text
    br14 = br4.Text
    tl14 = tl4.Text
    tr14 = tr4.Text

    Me.PictureBox1.Height = (i + bl1) - (i + tl1)
    Me.PictureBox1.Width = (i + br1) - (i + tr1)
    Me.GroupBox1.Height = (i + bl14) - (i + tl14)
    Me.GroupBox1.Width = (i + br14) - (i + tr14)

    Me.PictureBox1.Location = New Point(Me.PictureBox1.Location.X + (0 + tr.Text), Me.PictureBox1.Location.Y + (0 + tl.Text))
    Me.GroupBox1.Location = New Point(Me.GroupBox1.Location.X + (0 + tr4.Text), Me.GroupBox1.Location.Y + (0 + tl4.Text))
    Timer7.Stop()
End Sub

I need to check for null before commencing and am having a problem.

Answer 1

It's possible that the timer tick event is executed before initialization is complete. Try leaving the timers disabled, then enable them in the form "shown" event.