In Windows Forms application, we can use Control.IsInDesignMode or LicenseManager.UsageMode == LicenseUsageMode.Designtime to check whether your code is executing in DesignMode or not. You might wonder how would you do the same in WPF. Fortunately, Cider and Blend offers a similar functionality. You can test the following condition DesignerProperties.GetIsInDesignMode(new DependencyObject()).