How to Change Theme Realtime Problem With Lose data when Changing.

[Watit]

How to Change Theme Realtime Problem With Lose data when Changing.

StyleManager.ApplicationTheme = new Office_BlackTheme();
GridChild.Children.Add(new moduleDataGrid(fwSL));

When i use  

GridChild.Children.Add(new moduleDataGrid(fwSL));

I'm necessary must to Use it Bring use DLL from External project import and set Theme
But When use new moduleDataGrid(fwSL) My data it Lose.
Help me Please.
Thank You.