IsInDesign
Provides a mechanism to wrap WPF user control code that causes an exception on the host WPF window. Notes: I use a separate DLL for all of my extensions which can cause additional challenges. Here are some tips; There are 3 assemblies required 2 of which are easy to add unless you know there nuances; "System.Windows.Controls" this requires "PresentationCore" & "PresentationFramework". "System.Windows" was the most interesting. Look for WindowsBase.DLL if you don't find a reference. Be sure it matches the .Net Framework version you are using..
Source
namespace ExtensionMethods
{
public static class WPFUserControlExtensions
{
public static bool IsInDesignMode(this UserControl uc)
{
return ((bool)(DesignerProperties.IsInDesignModeProperty.GetMetadata(typeof(DependencyObject)).DefaultValue)) ;
}
}
}Example
public partial class MyUserControl : UserControl
{
public MyUserControl()
{
InitializeComponent();
}
//this is only an example but is a valid illustration
//in the host WPF window you get an
// System.Exception... unable to open database file
// by using the "extension IsInDesignMode" the control loads fine
private void UserControl_Loaded(object sender, RoutedEventArgs e)
{
if (!this.IsInDesignMode())
{
SQLiteDatabase db = new SQLiteDatabase("..\\..\\Data\\ComboBoxItems.db");
if (db != null)
{
string query =
"Select * From ComboBoxItems";
m_gridRowItems = db.GetDataTable(query);
}
if (GridRowItems != null)
GenericGrid.ItemsSource = new DataGridCollectionView(GridRowItems.DefaultView);
}
}
}
}