Reference to GUI element by name as string - wpf

Question

How can i reference to a GUI element by it's name as String for all elements, even the ones in grids inside tab items.
Now i have this code:
Module VisualExtensions
<System.Runtime.CompilerServices.Extension>
Public Iterator Function GetVisualChildren(Of T As Visual)(parent As DependencyObject) As IEnumerable(Of T)
Dim child As T = Nothing
Dim numVisuals As Integer = VisualTreeHelper.GetChildrenCount(parent)
For i As Integer = 0 To numVisuals - 1
Dim v As Visual = DirectCast(VisualTreeHelper.GetChild(parent, i), Visual)
child = TryCast(v, T)
If v IsNot Nothing Then
For Each item In GetVisualChildren(Of T)(v)
Yield item
Next
End If
If child IsNot Nothing Then
Yield child
End If
Next
End Function
End Module
Which is called by this piece of code:
Try
For Each s In output
Dim nameOfControl = s
Dim window = Windows.Application.Current.Windows(0)
Dim visuals = GetVisualChildren(Of FrameworkElement)(window)
Dim child = visuals.OfType(Of FrameworkElement)()
Dim match = child.FirstOrDefault(Function(x) x.Name = nameOfControl)
match.Visibility = Visibility.Collapsed
Next
Catch ex As NullReferenceException
Finally
End Try
If s is "veleprodajaTab" it works well (code collapses that tab) and xml for that tab is:
<TabItem x:FieldModifier="public" x:Name="veleprodajaTab" Header="Maloprodaja" FontSize="10" VerticalAlignment="Bottom">
But if s is "buttonRefresh" it does not work, it can't reference to that object. I get a nullreferenceexception in debug child is Nothing
Code for "buttonRefresh" (with grids surounding it):
<TabItem x:FieldModifier="public" x:Name="maloprodajaTab"...
<Grid x:FieldModifier="public" x:Name="maloprodajaTabGrid"...
<Grid x:FieldModifier="public" x:Name="gridFckp"
<Button x:FieldModifier="public" x:Name="buttonRefresh" Content="Refresh" HorizontalAlignment="Left" Margin="276,6,0,0" VerticalAlignment="Top" Width="75" Grid.ColumnSpan="2"/>
</grid>
</grid>
I can't seem to reference to anything inside **TabItem **
If i try to set window.buttonRefresh.Visibility = Visibility.Collapsed code works but there is a problem with referencing to childs inside grids

Answer 1

You can't since the TabControl is virtualized. You need to navigate the Visual Tree passing it the name of the element you need. Have a look here:
Find WPF controls by name or type
So you can do something like this:
private T FindChildByname<T>(DependencyObject parent, string name) where T : FrameworkElement
{
T child = default(T);
for (int i = 0; i < VisualTreeHelper.GetChildrenCount(parent); i++)
{
var ch = VisualTreeHelper.GetChild(parent, i);
child = ch as T;
if (child != null && child.Name == name)
break;
else
child = FindChildByname<T>(ch, name);
if (child != null) break;
}
return child;
}
And call it like:
Button button = FindChildByname<Button>(maloprodajaTabGrid, "buttonRefresh");