[WPF] Design Mode

WPF

if (DesignerProperties.GetIsInDesignMode(new System.Windows.DependencyObject()))

{

  // Design Time Code

}

else

{

  // Runtime Code

}

WindowPhone, Silverlight

if (DesignerProperties.IsInDesignTool)

{

  // Design Time Code

}

else

{

  // Runtime Code

}

Windows Store

if (DesignerProperties.DesignModeEnabled)

{

  // Design Time Code

}

else

{

  // Runtime Code

}