Can the position and szing of a control element in a View be controlled from the ViewModel?

Question

Is it possible to change the position of a control, say a label, as a response to some action/operation from the ViewModel?  Like if one response to something is true then place the label in the top left corner.  If false, place the label
in the lower right corner.  I realize you could have a label in each position and just set the visibility.  But can the position and sizing of said label be controlled from the View Model?  What would be a sample coding of this?  would
it be in the xaml or combination of a method in the ViewModel and the xaml? 
Rich P

Answer 1

First off Rich, say TextBlock to yourself ten times.
Use a TextBlock rather than a label.
There are a bunch of different ways to do this and the easiest is to have two controls whose text is bound to the one property.
Bind the Visibility of each to another 2 properties in the viewmodel.
Collapse one and Visible the other.
The reason for that is that it's easier.
Technically, you could put one textblock in a grid and use margin to control this.  You could animate x y co-ordinates and move the textblock mysteriously across the window if you put your mind to it.
Or you could put it in a row/column "cell" of a grid and change which cell it goes in - but that would involve some mechanism like messaging from the viewmodel to the view and is not really ideal if you can avoid it.
I'd have a pair of textblocks, here's one:
<TextBlock Name="TopLeftMsg"
Text="{Binding Msg}"
Visiblity="{Binding TopLeftVis}"
Both would bind to a public string property msg in the viewmodel.
They each get their own public visibility property  and that'd be switched between Visibility.Visible and Visibility.Collapsed.
Sizing of textblocks is best fitted to content because all you see is the text.
Textboxes are arguably different because you can see the things.
Hope that helps.
Recent Technet articles:
Property List Editing;  
Dynamic XAML