How can I access the ListViewItems of a WPF ListView?

<ListView x:Name="myList" ItemsSource="{Binding SomeList}">
    <ListView.View>
        <GridView>
            <GridViewColumn>
                <GridViewColumn.CellTemplate>
                    <DataTemplate>
                        <!-- Focus this! -->
                        <TextBox x:Name="myBox"/>

(myList.FindName("myBox") as TextBox).Focus();

private void myList_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
    if (myList.SelectedItem != null)
    {
    	object o = myList.SelectedItem;
    	ListViewItem lvi = (ListViewItem)myList.ItemContainerGenerator.ContainerFromItem(o);
    	TextBox tb = FindByName("myBox", lvi) as TextBox;

    	if (tb != null)
    		tb.Dispatcher.BeginInvoke(new Func<bool>(tb.Focus));
    }
}

private FrameworkElement FindByName(string name, FrameworkElement root)
{
    Stack<FrameworkElement> tree = new Stack<FrameworkElement>();
    tree.Push(root);

    while (tree.Count > 0)
    {
    	FrameworkElement current = tree.Pop();
    	if (current.Name == name)
    		return current;

    	int count = VisualTreeHelper.GetChildrenCount(current);
    	for (int i = 0; i < count; ++i)
    	{
    		DependencyObject child = VisualTreeHelper.GetChild(current, i);
    		if (child is FrameworkElement)
    			tree.Push((FrameworkElement)child);
    	}
    }

    return null;
}

var item = new SomeListItem();
SomeList.Add(item);
ListViewItem = SomeList.ItemContainerGenerator.ContainerFromItem(item); // returns null

<DataTemplate x:Name="foo">
  <!-- Focus this! -->
  <TextBox x:Name="myBox"/>

var tb = foo.FindName("myBox");

Private Sub SelectAllText(ByVal cell As DataGridCell)
    If cell IsNot Nothing Then
        Dim txtBox As TextBox= GetVisualChild(Of TextBox)(cell)
        If txtBox IsNot Nothing Then
            txtBox.Focus()
            txtBox.SelectAll()
        End If
    End If
End Sub

Public Shared Function GetVisualChild(Of T As {Visual, New})(ByVal parent As Visual) As 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 = TryCast(VisualTreeHelper.GetChild(parent, i), Visual)
        If v IsNot Nothing Then
            child = TryCast(v, T)
            If child Is Nothing Then
                child = GetVisualChild(Of T)(v)
            Else
                Exit For
            End If
        End If
    Next
    Return child
End Function

//textbox can be catched like this.
       var textBox = ((TextBox)sender);


        EmailValidation(textBox.Text);
    }