[RESOLVED] Listview clear/adding items blinking, best approach to stop the blink

[Schmidt]

... now a new question can you add widgets to normal vb forms?

Yes, there's an older, still supported mode - which involves the definition and usage
of a generic (Std-Exe-Project-Private) UserControl (Code for that "ucPanel" further below).

In conjunction with that ucPanel-Control you can then host Widgets (in the ucPanel)
together with normal VB-Controls on normal VB-Forms (including proper Tabbing-
and Focus-delegation then).

Below I'll post an example for that.

...or do I have to work with the new form that contains the widget...

Why not, working directly with the new Form-Engine is recommended - and vbWidgets.dll
contains enough Widget-Encapsulations to replace nearly anything you use on your old VB-Forms.

The example below shows (in addition to the two cwVList-Widgets) also a cwButton-
as well as a cwTextBox-Widget (just to demonstrate that it's not that hard to work with that).

...or perhaps can I move the whole tool form/widget into a normal form (SetParent api) what would you suggest.

No, wouldn't recommend that - the ucPanel-Mode which I describe now in an example -
is thought for that:

ucPanel-Mode:
In case you want to mix normal VB-Controls on a normal VB-Form with Widgets,
it works best (with regards to tabbing and focus-stuff), when you introduce a small,
normal VB-UserControl which then acts as a ContainerHost for an RC5-cWidgetRoot -
and can be used in a generic way (allowing any amount of cwWidget-Classes to be
added over the Widgets-Collection it exposes in a Property).

One can place multiple ucPanels on the same normal VB-Form (each hosting different Widgets) -
but I'd recommend to "bundle as many Widgets in the same ucPanel-Container as possible"
(to save some resources - using an ucPanel for each and every small single cwTextbox or cwLabel
would be overkill resource-wise).

So the below example avoids that (hosting two cwVlist-Widgets, a cwButton and a cwTextBox,
on a single ucPanel).

Here's a ScreenShot how that looks like on a normal VB-Form (I've set the BackColor of the
ucPanel-WidgetRoot to vbWhite, so that one can better see, which range it covers on the VB-Form).



To test the following Demo-Code one would again need to put references into
a normal, fresh VB6-Std-Project (to vbRichClient5 and vbWidgets as well).

Now we need (in addition to the normal VB-Form, Form1) only one additional
Code-Module: a UserControl-Module, which should be named ucPanel.

The following code needs to be pasted into it:

Option Explicit
 
Event BubblingEvent(Sender As Object, EventName As String, P1, P2, P3, P4, P5, P6, P7)
Event ResizeWithDimensions(ByVal NewWidth As Long, ByVal NewHeight As Long)
Event DragOverDst(Data As vbRichClient5.cDataObject, ByVal AllowedEffects As vbRichClient5.WidgetDropEffects, Effect As vbRichClient5.WidgetDropEffects, Button As Integer, Shift As Integer, x As Single, y As Single)
Event DragDropDst(Data As vbRichClient5.cDataObject, ByVal AllowedEffects As vbRichClient5.WidgetDropEffects, Effect As vbRichClient5.WidgetDropEffects, Button As Integer, Shift As Integer, x As Single, y As Single)
Event NewWidgetCreateDimensions(ParentWidget As cWidgetBase, ByVal x As Single, ByVal y As Single, ByVal dx As Single, ByVal dy As Single)

Private WithEvents mWidgetRoot As cWidgetRoot

Private Sub UserControl_Initialize()
  ScaleMode = vbPixels
End Sub

Public Property Get WidgetRoot() As cWidgetRoot
  If mWidgetRoot Is Nothing Then 'let's create the Root-Object and hold it in mWidgetRoot
    Set mWidgetRoot = Cairo.WidgetRoot
        mWidgetRoot.RenderContentIn Me
  End If
  Set WidgetRoot = mWidgetRoot
End Property

Public Property Get Widgets() As cWidgets 'this hands out the WidgetRoots-Widgets-Collection directly, to spare an indirection
  Set Widgets = WidgetRoot.Widgets
End Property

Public Property Get ScaleWidth() As Single
  ScaleWidth = UserControl.ScaleWidth
End Property
Public Property Get ScaleHeight() As Single
  ScaleHeight = UserControl.ScaleHeight
End Property

'what remains is event-redirection/reraising to be compatible here as well (to the cWidgetForms)
Private Sub mWidgetRoot_ResizeWithDimensions(ByVal NewWidth As Long, ByVal NewHeight As Long)
  RaiseEvent ResizeWithDimensions(NewWidth, NewHeight)
End Sub
Private Sub mWidgetRoot_BubblingEvent(Sender As Object, EventName As String, P1, P2, P3, P4, P5, P6, P7)
  RaiseEvent BubblingEvent(Sender, EventName, P1, P2, P3, P4, P5, P6, P7)
End Sub
Private Sub mWidgetRoot_DragDropDst(Data As vbRichClient5.cDataObject, ByVal AllowedEffects As vbRichClient5.WidgetDropEffects, Effect As vbRichClient5.WidgetDropEffects, Button As Integer, Shift As Integer, x As Single, y As Single)
  RaiseEvent DragDropDst(Data, AllowedEffects, Effect, Button, Shift, x, y)
End Sub
Private Sub mWidgetRoot_DragOverDst(Data As vbRichClient5.cDataObject, ByVal AllowedEffects As vbRichClient5.WidgetDropEffects, Effect As vbRichClient5.WidgetDropEffects, Button As Integer, Shift As Integer, x As Single, y As Single)
  RaiseEvent DragOverDst(Data, AllowedEffects, Effect, Button, Shift, x, y)
End Sub
Private Sub mWidgetRoot_NewWidgetCreateDimensions(ParentWidget As vbRichClient5.cWidgetBase, ByVal x As Single, ByVal y As Single, ByVal dx As Single, ByVal dy As Single)
  RaiseEvent NewWidgetCreateDimensions(ParentWidget, x, y, dx, dy)
End Sub

Now, close the ucPanel-Code-Module (as well as its visual representation) - and
drag a new instance of it up in an appropriate size (as seen on the ScreenShot above)
onto your Form1 (leave the Default-Name it gets - ucPanel1 - as it is).

Now the following code needs to be pasted into Form1, before running the project:

Option Explicit
  
Private MemDB As cMemDB
Private WithEvents tmrUpdates As cTimer, WithEvents tmrRefresh As cTimer
Private RsBids As cRecordset, lstBids As cwVList
Private RsAsks As cRecordset, lstAsks As cwVList
Private btnTest As cwButton, txtTest As cwTextBox 'just to introduce some other Widgets, also shown on the Panel

Private Sub Form_Load()
  Cairo.ImageList.AddIconFromResourceFile "LstIco", "shell32.dll", 322, 32, 32 'add an image-resource
  Cairo.ImageList.AddIconFromResourceFile "BtnIco", "shell32.dll", 167, 32, 32 'add an image-resource

  Set MemDB = New_c.MemDB 'create a Demo-Instance of the global MemDB
      MemDB.Exec "Create Table SomeBids(Amount Text, Price Text)" 'and add a simple table to it
      MemDB.Exec "Create Table SomeAsks(Amount Text, Price Text)" 'and add a simple table to it
  
  Dim i As Long
  For i = 1 To 20 'add a few Demo-Records
    MemDB.ExecCmd "Insert Into SomeBids Values(?,?)", Str(i), Str(i + 0.01)
    MemDB.ExecCmd "Insert Into SomeAsks Values(?,?)", Str(-i), Str(-i - 0.01)
  Next i
  
  Set tmrUpdates = New_c.Timer(2000, True)
  Set tmrRefresh = New_c.Timer(1000, True)
  
  Me.Show 'it's good to show the Form, before adding the Widgets to the ucPanel
  Set lstBids = ucPanel1.Widgets.Add(New cwVList, "lstBids", 4, 4, 200, 300)
  Set lstAsks = ucPanel1.Widgets.Add(New cwVList, "lstAsks", 208, 4, 200, 300)
  Set btnTest = ucPanel1.Widgets.Add(New cwButton, "btnTest", 430, 4, 120, 22)
      btnTest.Widget.ImageKey = "BtnIco"
      btnTest.Caption = "&Button-Widget"
  Set txtTest = ucPanel1.Widgets.Add(New cwTextBox, "txtTest", 430, 30, 120, 22)
      txtTest.CueBannerText = "Type something..."
  ucPanel1.WidgetRoot.BackColor = vbWhite '<- just to make the area of the ucPanel more obvious on the VB-Form here
  ucPanel1.WidgetRoot.Refresh
End Sub

Private Sub tmrUpdates_Timer()
  SimulateChangesInTable MemDB.GetRs("Select * From SomeBids")
  SimulateChangesInTable MemDB.GetRs("Select * From SomeAsks")
End Sub

Private Sub SimulateChangesInTable(Rs As cRecordset)
  Rs!Price = Str(Val(Rs!Price.Value) + 0.01)  'change the Price of the first record
  Rs.MoveNext
  Rs!Price = Str(Val(Rs!Price.Value) + 0.01) 'change the Price of the second record

  Rs.AddNew 'and add a new Record to expand the MemDB-Tables content a bit
    Rs!Amount = Str(Rs.RecordCount)
    Rs!Price = Str(Rs.RecordCount + 0.01)
  Rs.UpdateBatch 'just to update the MemDB-Table in each round with some new Data
End Sub

Private Sub tmrRefresh_Timer()
  RefreshListData lstBids, RsBids, "Select * From SomeBids"
  RefreshListData lstAsks, RsAsks, "Select * From SomeAsks"
End Sub

Private Sub RefreshListData(Lst As cwVList, Rs As cRecordset, SQL As String)
  Set Rs = MemDB.GetRs(SQL)  'get the latest Data-Snapshot from the MemDB
  Lst.HeaderHeight = 44
  Lst.RowHeight = 21
  Lst.ListCount = Rs.RecordCount 'that's all what's needed to enforce a Refresh on the lstBids
End Sub

Private Sub ucPanel1_BubblingEvent(Sender As Object, EventName As String, P1, P2, P3, P4, P5, P6, P7)
  Select Case EventName
    Case "OwnerDrawHeader": DrawListHeader IIf(Sender Is lstBids, RsBids, RsAsks), P1, P2, P3
    Case "OwnerDrawItem":   DrawListItem IIf(Sender Is lstBids, RsBids, RsAsks), P1, P2, P3, P4
    Case "Click":           If Sender Is btnTest Then MsgBox "Hello from Widget-Button"
    Case "Change":          If Sender Is txtTest Then Caption = txtTest.Text 'just reflect it in the Form-Caption
  End Select
End Sub

Private Sub DrawListItem(Rs As cRecordset, ByVal Index As Long, ByVal CC As cCairoContext, ByVal dx As Single, ByVal dy As Single)
  CC.RenderSurfaceContent "LstIco", 6, 2, 16, 16
  
  CC.DrawText 24, 0, dx \ 2 - 24, dy, Rs.ValueMatrix(Index, 0), True, vbLeftJustify, 2, True
  CC.DrawText dx \ 2, 0, dx \ 2, dy, Rs.ValueMatrix(Index, 1), True, vbRightJustify, 2, True
     
  CC.DrawLine dx \ 2, 0, dx \ 2, dy, True, 1, vbBlack, 0.1 'draw a vertical Col-Separator (if wanted)
End Sub

Private Sub DrawListHeader(Rs As cRecordset, ByVal CC As cCairoContext, ByVal dx As Single, ByVal dy As Single)
  Cairo.Theme.DrawTo CC, lstBids.Widget, thmTypeButtonFace, 0, 0, 0, dx, dy

  CC.SelectFont "Tahoma", 10, &H444444, True 'text-rendering again (this time with a somewhat larger font)
  CC.DrawText 0, 0, dx, dy \ 2, IIf(Rs Is RsBids, "Bids", "Asks"), True, vbCenter, 2, True
  
  CC.DrawText 0, dy \ 2, dx \ 2, dy \ 2, Rs(0).Name, True, vbCenter, 2, True
  CC.DrawText dx \ 2, dy \ 2, dx \ 2, dy \ 2, Rs(1).Name, True, vbCenter, 2, True
  
  CC.DrawLine dx \ 2, dy \ 2, dx \ 2, dy, True, 1, vbBlack, 0.1   'draw a vertical Col-Separator (if wanted)
End Sub

Private Sub Form_Terminate()
  If Forms.Count = 0 Then New_c.CleanupRichClientDll
End Sub

In case you want more IDE-stability in this mode (allowing Stop-Button-presses for example) -
I'd recommend to download the latest RC5-version 5.0.29 which contains better protection in such cases.


HTH

Olaf