Merge pull request #1063 from HermanSchoenfeld/master

Added unhandled exception handling in Application.Run

Terminal.Gui/Core/Application.cs

@@ -67,7 +67,7 @@ namespace Terminal.Gui {
 		public static Toplevel Top { get; private set; }
 
 		/// <summary>
-		/// The current <see cref="Toplevel"/> object. This is updated when <see cref="Application.Run()"/> enters and leaves to point to the current <see cref="Toplevel"/> .
+		/// The current <see cref="Toplevel"/> object. This is updated when <see cref="Application.Run(Func{Exception, bool})"/> enters and leaves to point to the current <see cref="Toplevel"/> .
 		/// </summary>
 		/// <value>The current.</value>
 		public static Toplevel Current { get; private set; }
@@ -643,20 +643,20 @@ namespace Terminal.Gui {
 		}
 
 		/// <summary>
-		/// Runs the application by calling <see cref="Run(Toplevel)"/> with the value of <see cref="Top"/>
+		/// Runs the application by calling <see cref="Run(Toplevel, Func{Exception, bool})"/> with the value of <see cref="Top"/>
 		/// </summary>
-		public static void Run ()
+		public static void Run (Func<Exception, bool> errorHandler = null)
 		{
-			Run (Top);
+			Run (Top, errorHandler);
 		}
 
 		/// <summary>
-		/// Runs the application by calling <see cref="Run(Toplevel)"/> with a new instance of the specified <see cref="Toplevel"/>-derived class
+		/// Runs the application by calling <see cref="Run(Toplevel, Func{Exception, bool})"/> with a new instance of the specified <see cref="Toplevel"/>-derived class
 		/// </summary>
-		public static void Run<T> () where T : Toplevel, new()
+		public static void Run<T> (Func<Exception, bool> errorHandler = null) where T : Toplevel, new()
 		{
 			Init (() => new T ());
-			Run (Top);
+			Run (Top, errorHandler);
 		}
 
 		/// <summary>
@@ -669,10 +669,10 @@ namespace Terminal.Gui {
 		///     run other modal <see cref="View"/>s such as <see cref="Dialog"/> boxes.
 		///   </para>
 		///   <para>
-		///     To make a <see cref="Run(Toplevel)"/> stop execution, call <see cref="Application.RequestStop"/>.
+		///     To make a <see cref="Run(Toplevel, Func{Exception, bool})"/> stop execution, call <see cref="Application.RequestStop"/>.
 		///   </para>
 		///   <para>
-		///     Calling <see cref="Run(Toplevel)"/> is equivalent to calling <see cref="Begin(Toplevel)"/>, followed by <see cref="RunLoop(RunState, bool)"/>,
+		///     Calling <see cref="Run(Toplevel, Func{Exception, bool})"/> is equivalent to calling <see cref="Begin(Toplevel)"/>, followed by <see cref="RunLoop(RunState, bool)"/>,
 		///     and then calling <see cref="End(RunState)"/>.
 		///   </para>
 		///   <para>
@@ -682,13 +682,33 @@ namespace Terminal.Gui {
 		///     the <see cref="RunLoop(RunState, bool)"/> method will only process any pending events, timers, idle handlers and
 		///     then return control immediately.
 		///   </para>
+		///   <para>
+		///     When <paramref name="errorHandler"/> is null the exception is rethrown, when it returns true the application is resumed and when false method exits gracefully.
+		///   </para>
 		/// </remarks>
 		/// <param name="view">The <see cref="Toplevel"/> tu run modally.</param>
-		public static void Run (Toplevel view)
+		/// <param name="errorHandler">Handler for any unhandled exceptions (resumes when returns true, rethrows when null).</param>
+		public static void Run (Toplevel view, Func<Exception, bool> errorHandler = null)
 		{
-			var runToken = Begin (view);
-			RunLoop (runToken);
-			End (runToken);
+			var resume = true;
+			while (resume)
+			{
+				try
+				{
+					resume = false;
+					var runToken = Begin (view);
+					RunLoop (runToken);
+					End (runToken);
+				}
+				catch (Exception error)
+				{
+					if (errorHandler == null)
+					{
+						throw;
+					}
+					resume = errorHandler(error);
+				}
+			}
 		}
 
 		/// <summary>
@@ -696,7 +716,7 @@ namespace Terminal.Gui {
 		/// </summary>
 		/// <remarks>
 		///   <para>
-		///   This will cause <see cref="Application.Run()"/> to return.
+		///   This will cause <see cref="Application.Run(Func{Exception, bool})"/> to return.
 		///   </para>
 		///   <para>
 		///     Calling <see cref="Application.RequestStop"/> is equivalent to setting the <see cref="Toplevel.Running"/> property on the curently running <see cref="Toplevel"/> to false.

Terminal.Gui/Core/Toplevel.cs

@@ -15,7 +15,7 @@ namespace Terminal.Gui {
 	/// </summary>
 	/// <remarks>
 	///   <para>
-	///     Toplevels can be modally executing views, started by calling <see cref="Application.Run(Toplevel)"/>. 
+	///     Toplevels can be modally executing views, started by calling <see cref="Application.Run(Toplevel, Func{Exception, bool})"/>. 
 	///     They return control to the caller when <see cref="Application.RequestStop()"/> has 
 	///     been called (which sets the <see cref="Toplevel.Running"/> property to false). 
 	///   </para>
@@ -23,7 +23,7 @@ namespace Terminal.Gui {
 	///     A Toplevel is created when an application initialzies Terminal.Gui by callling <see cref="Application.Init(ConsoleDriver, IMainLoopDriver)"/>.
 	///     The application Toplevel can be accessed via <see cref="Application.Top"/>. Additional Toplevels can be created 
 	///     and run (e.g. <see cref="Dialog"/>s. To run a Toplevel, create the <see cref="Toplevel"/> and 
-	///     call <see cref="Application.Run(Toplevel)"/>.
+	///     call <see cref="Application.Run(Toplevel, Func{Exception, bool})"/>.
 	///   </para>
 	///   <para>
 	///     Toplevels can also opt-in to more sophisticated initialization
@@ -57,7 +57,7 @@ namespace Terminal.Gui {
 		/// <summary>
 		/// Fired once the Toplevel's <see cref="MainLoop"/> has started it's first iteration.
 		/// Subscribe to this event to perform tasks when the <see cref="Toplevel"/> has been laid out and focus has been set.
-		/// changes. A Ready event handler is a good place to finalize initialization after calling `<see cref="Application.Run()"/>(topLevel)`.
+		/// changes. A Ready event handler is a good place to finalize initialization after calling `<see cref="Application.Run(Func{Exception, bool})"/>(topLevel)`.
 		/// </summary>
 		public event Action Ready;
 
@@ -469,7 +469,7 @@ namespace Terminal.Gui {
 		}
 
 		/// <summary>
-		/// Invoked by <see cref="Application.Begin"/> as part of the <see cref="Application.Run(Toplevel)"/> after
+		/// Invoked by <see cref="Application.Begin"/> as part of the <see cref="Application.Run(Toplevel, Func{Exception, bool})"/> after
 		/// the views have been laid out, and before the views are drawn for the first time.
 		/// </summary>
 		public virtual void WillPresent ()

Terminal.Gui/Windows/Dialog.cs

@@ -15,7 +15,7 @@ namespace Terminal.Gui {
 	/// or more <see cref="Button"/>s. It defaults to the <see cref="Colors.Dialog"/> color scheme and has a 1 cell padding around the edges.
 	/// </summary>
 	/// <remarks>
-	///  To run the <see cref="Dialog"/> modally, create the <see cref="Dialog"/>, and pass it to <see cref="Application.Run()"/>. 
+	///  To run the <see cref="Dialog"/> modally, create the <see cref="Dialog"/>, and pass it to <see cref="Application.Run(Func{Exception, bool})"/>. 
 	///  This will execute the dialog until it terminates via the [ESC] or [CTRL-Q] key, or when one of the views
 	///  or buttons added to the dialog calls <see cref="Application.RequestStop"/>.
 	/// </remarks>

Terminal.Gui/Windows/FileDialog.cs

@@ -670,7 +670,7 @@ namespace Terminal.Gui {
 	/// <remarks>
 	/// <para>
 	///   To use, create an instance of <see cref="SaveDialog"/>, and pass it to
-	///   <see cref="Application.Run()"/>. This will run the dialog modally,
+	///   <see cref="Application.Run(Func{Exception, bool})"/>. This will run the dialog modally,
 	///   and when this returns, the <see cref="FileName"/>property will contain the selected file name or 
 	///   null if the user canceled. 
 	/// </para>
@@ -713,7 +713,7 @@ namespace Terminal.Gui {
 	/// </para>
 	/// <para>
 	///   To use, create an instance of <see cref="OpenDialog"/>, and pass it to
-	///   <see cref="Application.Run()"/>. This will run the dialog modally,
+	///   <see cref="Application.Run(Func{Exception, bool})"/>. This will run the dialog modally,
 	///   and when this returns, the list of filds will be available on the <see cref="FilePaths"/> property.
 	/// </para>
 	/// <para>