[FancyZones editor] Rudimentary crash handler (#6783)

* Handle crashes in the FZ editor

* Removed reference to .NET frameworks, added a message box

* log => txt

* Update text shown

src/modules/fancyzones/editor/FancyZonesEditor/App.xaml.cs

@@ -3,7 +3,12 @@
 // See the LICENSE file in the project root for more information.
 
 using System;
+using System.Collections.Generic;
+using System.Globalization;
+using System.IO;
+using System.Linq;
 using System.Runtime.InteropServices;
+using System.Text;
 using System.Threading.Tasks;
 using System.Windows;
 using FancyZonesEditor.Models;
@@ -25,6 +30,8 @@ namespace FancyZonesEditor
 
         private void OnStartup(object sender, StartupEventArgs e)
         {
+            AppDomain.CurrentDomain.UnhandledException += OnUnhandledException;
+
             RunnerHelper.WaitForPowerToysRunner(Settings.PowerToysPID, () =>
             {
                 Environment.Exit(0);
@@ -66,5 +73,94 @@ namespace FancyZonesEditor
             overlay.Show();
             overlay.DataContext = foundModel;
         }
+
+        private void OnUnhandledException(object sender, UnhandledExceptionEventArgs args)
+        {
+            var fileStream = File.OpenWrite("FZEditorCrashLog.txt");
+            var sw = new StreamWriter(fileStream);
+            sw.Write(FormatException((Exception)args.ExceptionObject));
+            fileStream.Close();
+            MessageBox.Show("Error logged to " + Path.GetFullPath(fileStream.Name) + "\nPlease report the bug to https://aka.ms/powerToysReportBug", "FancyZones Editor Error");
+        }
+
+        private string FormatException(Exception ex)
+        {
+            var sb = new StringBuilder();
+            sb.AppendLine();
+            sb.AppendLine("## Exception");
+            sb.AppendLine();
+            sb.AppendLine("```");
+
+            var exlist = new List<StringBuilder>();
+
+            while (ex != null)
+            {
+                var exsb = new StringBuilder();
+                exsb.Append(ex.GetType().FullName);
+                exsb.Append(": ");
+                exsb.AppendLine(ex.Message);
+                if (ex.Source != null)
+                {
+                    exsb.Append("   Source: ");
+                    exsb.AppendLine(ex.Source);
+                }
+
+                if (ex.TargetSite != null)
+                {
+                    exsb.Append("   TargetAssembly: ");
+                    exsb.AppendLine(ex.TargetSite.Module.Assembly.ToString());
+                    exsb.Append("   TargetModule: ");
+                    exsb.AppendLine(ex.TargetSite.Module.ToString());
+                    exsb.Append("   TargetSite: ");
+                    exsb.AppendLine(ex.TargetSite.ToString());
+                }
+
+                exsb.AppendLine(ex.StackTrace);
+                exlist.Add(exsb);
+
+                ex = ex.InnerException;
+            }
+
+            foreach (var result in exlist.Select(o => o.ToString()).Reverse())
+            {
+                sb.AppendLine(result);
+            }
+
+            sb.AppendLine("```");
+            sb.AppendLine();
+
+            sb.AppendLine("## Environment");
+            sb.AppendLine($"* Command Line: {Environment.CommandLine}");
+            sb.AppendLine($"* Timestamp: {DateTime.Now.ToString(CultureInfo.InvariantCulture)}");
+            sb.AppendLine($"* OS Version: {Environment.OSVersion.VersionString}");
+            sb.AppendLine($"* IntPtr Length: {IntPtr.Size}");
+            sb.AppendLine($"* x64: {Environment.Is64BitOperatingSystem}");
+            sb.AppendLine($"* CLR Version: {Environment.Version}");
+            sb.AppendLine("## Assemblies - " + AppDomain.CurrentDomain.FriendlyName);
+            sb.AppendLine();
+            foreach (var ass in AppDomain.CurrentDomain.GetAssemblies().OrderBy(o => o.GlobalAssemblyCache ? 50 : 0))
+            {
+                sb.Append("* ");
+                sb.Append(ass.FullName);
+                sb.Append(" (");
+
+                if (ass.IsDynamic)
+                {
+                    sb.Append("dynamic assembly doesn't has location");
+                }
+                else if (string.IsNullOrEmpty(ass.Location))
+                {
+                    sb.Append("location is null or empty");
+                }
+                else
+                {
+                    sb.Append(ass.Location);
+                }
+
+                sb.AppendLine(")");
+            }
+
+            return sb.ToString();
+        }
     }
 }