[2005] Open and closing forms

[rblumenthal]

Ok here is what I am trying to do. I have a form that has an option to view event logs, when that button is clicked this is what i want it to do

pop up a window that just has a progressbar that will run as a loading bar,
but the other window that will display the logs i want to be opened at the same time, but not visible bc it sometiems takes time to load all the logs, then after a certain time the progressbar window will close and the viewlog window will become visible. for whatever reason i got lost on what to do.

[Shaggy Hiker]

So for form2, you want to create it and load all the controls before calling either Show or ShowDialog. Since you wouldn't want the app to hang while you are loading the form, you probably want to do the loading in a background thread. Here's some code from a form where I did that:

    Private Sub New()

        ' This call is required by the Windows Form Designer.
        InitializeComponent()

        ' Add any initialization after the InitializeComponent() call.
        mNotNow = True
    End Sub

    Public Shared Sub Initialize()
        PICTransect = New PICTransectCustom
    End Sub

    Public Sub SetUp(ByVal cnStr As String)
        Me.lMess1.Text = "Loading..."
        Me.lMess2.Text = "...Please Wait"
        mConnectionString = cnStr
        uiContext = System.Threading.SynchronizationContext.Current
        mMut1 = New System.Threading.Mutex
        mImValid = False
        mData = New DataSet
        mFillT1 = New Threading.Thread(AddressOf FillData)
        mFillT1.IsBackground = True
        mFillT1.Start()
    End Sub

    Private Sub FillData()
        Dim cn As New System.Data.OleDb.OleDbConnection(mConnectionString)
        Dim da As New System.Data.OleDb.OleDbDataAdapter
        Dim cmd As System.Data.OleDb.OleDbCommand = Nothing

        Try
            Try
                cn.Open()
            Catch ex As Exception
                mError = "Failed to Open"
                Return
            End Try

           'Just filled three tables in here, but removed the code for this example
        
        mImValid = True
        BindDataToCombo()
        uiContext.Post(AddressOf EventRaiser, Nothing)
    End Sub

    Private Sub BindDataToCombo()
        If dgvStreams.InvokeRequired Then
            Me.dgvStreams.Invoke(New MethodInvoker(AddressOf BindDataToCombo))
        Else
            If mImValid Then

                mNotNow = True
                Me.lbNamedTransect.DisplayMember = "Transect"
                Me.lbNamedTransect.ValueMember = "ID"
                Me.lbNamedTransect.DataSource = mdvTransect

                Me.dgvStreams.DataSource = mdvGrid
                Me.dgvStreams.Columns("HydroID").Visible = False

                Me.lbRouteStart.DisplayMember = "RouteName"
                Me.lbRouteStart.ValueMember = "HydroID"
                Me.lbRouteStart.DataSource = mdvRouteStart

                Me.lbRouteEnd.DisplayMember = "RouteName"
                Me.lbRouteEnd.ValueMember = "HydroID"
                Me.lbRouteEnd.DataSource = mdvRouteEnd

                Me.cbStreams.DisplayMember = "HName"
                Me.cbStreams.DataSource = mData.Tables("StreamTable")

                mNotNow = False
            Else
                Windows.Forms.MessageBox.Show(mError)
            End If
        End If
    End Sub

    Private Event LoadDone()

    Private Sub EventRaiser(ByVal state As Object)
        RaiseEvent LoadDone()
    End Sub

Note that the synchronization context is stored prior to starting the background thread. By doing this, I can raise the LoadDone event on the synchronization context of the UI thread, thereby raising the event in the UI thread.

Also, if you are wondering about the Shared Initialize, the reason for that is because the form in question is a Singleton construct.

[rblumenthal]

Ok thanks, im going to have to look at that and try to understand it haha

[Shaggy Hiker]

I can explain any piece you are wondering about.