Tree View Checkbox issue

Question

Hi All,
I am working on a WPF C# application which has a tree view. The tree view is populated by a set of model classes. Each element on the tree view except for the root node has a checkbox. The issue now is that when i check a checkbox, it is selecting all the checkboxes under the same parent level.
Instead i would want it to select all the child nodes under the parent node.

For instance:
RootNode
Parent1 Node
Child1
Child2
Parent2 Node
Child3
Child4

and so on.
The current behavior is such that if i check the checkbox beside Parent1 Node, it is selecting Parent2 Node as well and no child elements are selected.
Instead i would want it to check the checkboxes of Child1 and Child2 if i check the Parent1 Node.

Can anyone please help me on this??7894-checkbox-issue.txt
Thank you in advance!!

Accepted Answer

Hi, at first I recommend to change the XAML an then include additional logic in ViewModel. Try demo.

XAML:

Code:

Imports System.ComponentModel
Imports System.Runtime.CompilerServices

Namespace WpfApp016

  Public Class ViewModel

    Public Sub New()
      For i = 1 To 10
        Dim rnl As New RootNameList With {.RootSubnet = $"RootSubnet{i}"}
        For k = 1 To 10
          Dim hg As New HostGroup With {.GroupName = $"GroupName {k + i * 10}"}
          rnl.HostGroupName.Add(hg)
          For l = 1 To 10
            Dim h As New HostName() With {.Host = $"Host {l}"}
            AddHandler h.PropertyChanged, AddressOf hg.h_PropertyChanged
            hg.Host.Add(h)
          Next
        Next
        col.Add(rnl)
      Next
      cvs.Source = col
    End Sub

    Private cvs As New CollectionViewSource
    Private col As New AsyncObservableCollection(Of RootNameList)
    Public ReadOnly Property TreeViewDataCollection As ICollectionView
      Get
        Return cvs.View
      End Get
    End Property
  End Class

  Public Class RootNameList
    Public Property RootSubnet As String
    Public Property HostGroupName As New List(Of HostGroup)
  End Class

  Public Class HostGroup
    Implements INotifyPropertyChanged

    Private _IsParentChecked As Boolean? = False
    Public Property IsParentChecked As Boolean?
      Get
        Return Me._IsParentChecked
      End Get
      Set(value As Boolean?)
        If Not value.HasValue Then value = False
        Me._IsParentChecked = value
        For Each h In Host
          h.IsChildChecked = value
        Next
        OnPropertyChanged()
      End Set
    End Property
    Public Property GroupName As String
    Public Property Host As New List(Of HostName)

    Friend Sub h_PropertyChanged(sender As Object, e As PropertyChangedEventArgs)
      Dim iFalse As Integer = 0
      Dim iTrue As Integer = 0
      For Each h In Host
        If h.IsChildChecked Then iTrue += 1 Else iFalse += 1
      Next
      If iTrue > 0 And iFalse = 0 Then Me._IsParentChecked = True
      If iTrue = 0 And iFalse > 0 Then Me._IsParentChecked = False
      If iTrue > 0 And iFalse > 0 Then Me._IsParentChecked = Nothing
      OnPropertyChanged(NameOf(IsParentChecked))
    End Sub

    Public Event PropertyChanged As PropertyChangedEventHandler Implements INotifyPropertyChanged.PropertyChanged
    Private Sub OnPropertyChanged( Optional propName As String = "")
      RaiseEvent PropertyChanged(Me, New PropertyChangedEventArgs(propName))
    End Sub
  End Class

  Public Class HostName
    Implements INotifyPropertyChanged

    Private _IsChildChecked As Boolean? = False
    Public Property IsChildChecked As Boolean?
      Get
        Return Me._IsChildChecked
      End Get
      Set(value As Boolean?)
        Me._IsChildChecked = value
        OnPropertyChanged()
      End Set
    End Property
    Public Property Host As String

    Public Event PropertyChanged As PropertyChangedEventHandler Implements INotifyPropertyChanged.PropertyChanged
    Private Sub OnPropertyChanged( Optional propName As String = "")
      RaiseEvent PropertyChanged(Me, New PropertyChangedEventArgs(propName))
    End Sub
  End Class

End Namespace

Answer

Hi, try following demo:

And classes:

Imports System.ComponentModel
Imports System.Runtime.CompilerServices

Namespace WpfApp013

  Public Class ViewModel

    Public Sub New()
      For i = 1 To 10
        Dim rnl As New RootNameList With {.RootSubnet = $"RootSubnet{i}"}
        For k = 1 To 10
          Dim hg As New HostGroup With {.GroupName = $"GroupName {k + i * 10}"}
          rnl.HostGroupName.Add(hg)
          For l = 1 To 10
            hg.Host.Add(New HostName() With {.Host = $"Host {l}"})
          Next
        Next
        col.Add(rnl)
      Next
      cvs.Source = col
    End Sub

    Private cvs As New CollectionViewSource
    Private col As New AsyncObservableCollection(Of RootNameList)
    Public ReadOnly Property TreeViewDataCollection As ICollectionView
      Get
        Return cvs.View
      End Get
    End Property
  End Class

  Public Class RootNameList
    Public Property RootSubnet As String
    Public Property HostGroupName As New List(Of HostGroup)
  End Class

  Public Class HostGroup
    Private _IsParentChecked As Boolean
    Public Property IsParentChecked As Boolean
      Get
        Return Me._IsParentChecked
      End Get
      Set(value As Boolean)
        Me._IsParentChecked = value
        If value Then
          For Each h In Host
            h.IsChildChecked = True
          Next
        End If
      End Set
    End Property
    Public Property GroupName As String
    Public Property Host As New List(Of HostName)
  End Class

  Public Class HostName
    Implements INotifyPropertyChanged

    Private _IsChildChecked As Boolean
    Public Property IsChildChecked As Boolean
      Get
        Return Me._IsChildChecked
      End Get
      Set(value As Boolean)
        Me._IsChildChecked = value
        OnPropertyChanged()
      End Set
    End Property
    Public Property Host As String

    Public Event PropertyChanged As PropertyChangedEventHandler Implements INotifyPropertyChanged.PropertyChanged
    Private Sub OnPropertyChanged( Optional propName As String = "")
      RaiseEvent PropertyChanged(Me, New PropertyChangedEventArgs(propName))
    End Sub
  End Class

End Namespace

Tree View Checkbox issue

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