ExtraLayoutControl.vb

Imports System.Collections.Generic
Imports System.Windows
Imports System.Windows.Controls
Imports DevExpress.Xpf.LayoutControl

Namespace DXSample

    Public Class ExtraLayoutControl
        Inherits DevExpress.Xpf.LayoutControl.LayoutControl

        Protected Overrides Function OnMeasure(ByVal constraint As Size) As Size
            If constraint.Width = 0 AndAlso constraint.Height = 0 Then Return MyBase.OnMeasure(constraint)
            Dim maxConstraint As Size = New Size(Double.PositiveInfinity, Double.PositiveInfinity)
            Dim defaultConstraint As Size = constraint
            constraint = MyBase.OnMeasure(constraint)
            If Double.IsInfinity(defaultConstraint.Width) AndAlso Orientation = Orientation.Horizontal Then defaultConstraint.Width = constraint.Width
            If Double.IsInfinity(defaultConstraint.Height) AndAlso Orientation = Orientation.Vertical Then defaultConstraint.Height = constraint.Height
            Dim starCount As Double = 0
'#Region "Create GroupLists"
            Dim listPixel As List(Of ExtraLayoutGroup) = New List(Of ExtraLayoutGroup)()
            Dim listStar As List(Of ExtraLayoutGroup) = New List(Of ExtraLayoutGroup)()
            For Each child As UIElement In Children
                If TypeOf child Is ExtraLayoutGroup Then
                    If CType(child, ExtraLayoutGroup).LayoutItemSize.Value > 0 Then
                        Select Case CType(child, ExtraLayoutGroup).LayoutItemSize.GridUnitType
                            Case GridUnitType.Pixel
                                listPixel.Add(CType(child, ExtraLayoutGroup))
                            Case GridUnitType.Star
                                listStar.Add(CType(child, ExtraLayoutGroup))
                                starCount += CType(child, ExtraLayoutGroup).LayoutItemSize.Value
                        End Select
                    End If
                End If
            Next

            If listPixel.Count = 0 AndAlso listStar.Count = 0 Then Return constraint
'#End Region
'#Region "Resize Pixeled"
            For Each group As ExtraLayoutGroup In listPixel
                If Orientation = Orientation.Horizontal Then
                    group.Width = group.LayoutItemSize.Value
                Else
                    group.Height = group.LayoutItemSize.Value
                End If

                group.InvalidateMeasure()
                group.Measure(If((Orientation = Orientation.Horizontal), New Size(group.LayoutItemSize.Value, maxConstraint.Height), New Size(maxConstraint.Width, group.LayoutItemSize.Value)))
            Next

'#End Region
            constraint = MyBase.OnMeasure(defaultConstraint)
            If starCount = 0 Then Return constraint
            Dim starSize As Double = 0
'#Region "Calc StarSize"
            Dim usedSize As Double = If((Orientation = Orientation.Horizontal), constraint.Width, constraint.Height)
            For Each group As ExtraLayoutGroup In listStar
                usedSize -= If((Orientation = Orientation.Horizontal), group.DesiredSize.Width, group.DesiredSize.Height)
            Next

            Dim availableSize As Double =(If((Orientation = Orientation.Horizontal), defaultConstraint.Width, defaultConstraint.Height)) - usedSize
            starSize = availableSize / starCount
'#End Region
'#Region "Resize Starred"
            For Each group As ExtraLayoutGroup In listStar
                If Orientation = Orientation.Horizontal Then
                    group.Width = group.LayoutItemSize.Value * starSize
                Else
                    group.Height = group.LayoutItemSize.Value * starSize
                End If

                group.InvalidateMeasure()
                group.Measure(If((Orientation = Orientation.Horizontal), New Size(group.Width, maxConstraint.Height), New Size(maxConstraint.Width, group.Height)))
            Next

'#End Region
            Return MyBase.OnMeasure(constraint)
        End Function
    End Class
End Namespace