Read width value in runtime

When I read the width value of my GridColumn I get the default value set in xaml (640 pixels). But the column is much wider than that in runtime because it stretches according to the width of the browser. In runtime I want to scale some of my controls to match that but when I read the value of my column it still gives me the default value 640. Until I actually resize the column with a gridsplitter the correct value get through. Anyone know how I can get the REAL width of th开发者_JAVA技巧e column during runtime without me having to resize it first?

 Double a = this.Column1.Width.Value; // Gives me the default value of 640 while the column is much wider than that.

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Try

Double a = this.Column1.ActualWidth.Value;