Access to TextBoxes in all ListView rows - WPF - VB.NET - wpf

Question

How can I access to TextBoxes in all ListView rows? I have also tried the two-way method, but it is only one-way.
<ListView Name="ListViewParameters" >
<ListView.View>
<GridView>
<GridViewColumn Header="Value" Width="120" >
<GridViewColumn.CellTemplate>
<DataTemplate>
<TextBox x:Name="TextWidth" Text="{Binding Path=Width, UpdateSourceTrigger=PropertyChanged, Mode=TwoWay}" />
</DataTemplate>
</GridViewColumn.CellTemplate>
</GridViewColumn>
...
.
Private Sub MainWindow_Initialized(sender As Object, e As EventArgs) Handles Me.Initialized
ListViewParameters.ItemsSource = Parameters
End Sub
.
Public Structure Parameter
Private _width As Integer
Private _length As Integer
Private _height As Integer
Property Width() As Integer
Get
Return _width
End Get
Set(Value As Integer)
_width = Value
End Set
End Property
Property Length() As Integer
Get
Return _length
End Get
Set(Value As Integer)
_length = Value
End Set
End Property
Property Height() As Integer
Get
Return _height
End Get
Set(Value As Integer)
_height = Value
End Set
End Property
End Structure
Public ReadOnly Parameters As New ObservableCollection(Of Parameter)
My goal is to calculate the volume:
Private Sub ButtonCalculate_Click(sender As Object, e As RoutedEventArgs)
Dim volume As Integer = 1
For Each t As TextBox In ListParameters
volume *= CInt(t.Text)
Next
MsgBox(volume.ToString)
End Sub
(This is for learning only)