Ask user to create file when non-existing path provided via commandline.

src/Notepads/Controls/Dialog/FileCreateDialog.cs

@@ -0,0 +1,17 @@
+namespace Notepads.Controls.Dialog
+{
+    using System;
+
+    public class FileCreateDialog : NotepadsDialog
+    {
+        public FileCreateDialog(string filePath, Action createAction)
+        {
+            Title = ResourceLoader.GetString("GetFileOpenCreateNewFileReminderDialog_Title");
+            Content = string.Format(ResourceLoader.GetString("GetFileOpenCreateNewFileReminderDialog_Content"), filePath);
+            PrimaryButtonText = ResourceLoader.GetString("RevertAllChangesConfirmationDialog_PrimaryButtonText");
+            CloseButtonText = ResourceLoader.GetString("RevertAllChangesConfirmationDialog_CloseButtonText");
+
+            PrimaryButtonClick += (dialog, args) => { createAction(); };
+        }
+    }
+}

src/Notepads/Notepads.csproj

@@ -110,6 +110,7 @@
     <Compile Include="Commands\KeyboardCommand.cs" />
     <Compile Include="Commands\KeyboardCommandHandler.cs" />
     <Compile Include="Controls\Dialog\AppCloseSaveReminderDialog.cs" />
+    <Compile Include="Controls\Dialog\FileCreateDialog.cs" />
     <Compile Include="Controls\Dialog\FileRenameDialog.cs" />
     <Compile Include="Controls\Dialog\FileOpenErrorDialog.cs" />
     <Compile Include="Controls\Dialog\FileSaveErrorDialog.cs" />

src/Notepads/Package.appxmanifest

@@ -1181,5 +1181,6 @@
   <Capabilities>
     <Capability Name="internetClient" />
     <rescap:Capability Name="confirmAppClose"/>
+    <rescap:Capability Name="broadFileSystemAccess" />
   </Capabilities>
 </Package>

src/Notepads/Services/ActivationService.cs

@@ -4,6 +4,7 @@
     using Notepads.Utilities;
     using Notepads.Views.MainPage;
     using Windows.ApplicationModel.Activation;
+    using Windows.ApplicationModel.Resources;
     using Windows.UI.Xaml.Controls;
 
     public static class ActivationService
@@ -98,6 +99,10 @@ private static async Task CommandActivated(Frame rootFrame, CommandLineActivated
                 {
                     await mainPage.OpenFile(file);
                 }
+                else
+                {
+                    await mainPage.CreateAndOpenFile();
+                }
             }
         }
     }

src/Notepads/Strings/en-US/Resources.resw

@@ -693,4 +693,16 @@
     <value>File extension "{0}" is not supported at this moment</value>
     <comment>FileRenameError: Extension is not currently supported. {0} stands for the file extension string.</comment>
   </data>
+  <data name="GetFileOpenCreateNewFileReminderDialog_Content" xml:space="preserve">
+    <value>Create file "{0}"?</value>
+    <comment>GetFileOpenCreateNewFileReminderDialog: "Content" display text.  {0} stands for file name/path. You can change the order but DO NOT REMOVE it from the string.</comment>
+  </data>
+  <data name="GetFileOpenCreateNewFileReminderDialog_Title" xml:space="preserve">
+    <value>Can't find the path specified</value>
+    <comment>GetFileOpenCreateNewFileReminderDialog: "Title" display text.</comment>
+  </data>
+  <data name="GetFileOpenCreateNewFileReminderDialog_NotificationMsg_FileCreateError" xml:space="preserve">
+    <value>Failed to create "{0}"</value>
+    <comment>GetFileOpenCreateNewFileReminderDialog: Notification message when file creation fails.  {0} stands for file name/path. You can change the order but DO NOT REMOVE it from the string.</comment>
+  </data>
 </root>

src/Notepads/Utilities/FileSystemUtility.cs

@@ -33,6 +33,8 @@ public static class FileSystemUtility
 
         private const string WslRootPath = "\\\\wsl$\\";
 
+        private static string _lastErrorFileOpenPath = string.Empty;
+
         // https://stackoverflow.com/questions/62771/how-do-i-check-if-a-given-string-is-a-legal-valid-file-name-under-windows
         private static readonly Regex ValidWindowsFileNames = new Regex(@"^(?!(?:PRN|AUX|CLOCK\$|NUL|CON|COM\d|LPT\d)(?:\..+)?$)[^\x00-\x1F\xA5\\?*:\"";|\/<>]+(?<![\s.])$", RegexOptions.IgnoreCase);
 
@@ -268,8 +270,10 @@ public static async Task<StorageFile> GetFile(string filePath)
             {
                 return await StorageFile.GetFileFromPathAsync(filePath);
             }
-            catch
+            catch (Exception ex)
             {
+                if (ex is FileNotFoundException) _lastErrorFileOpenPath = filePath;
+
                 return null;
             }
         }
@@ -596,6 +600,27 @@ public static async Task<StorageFile> CreateFile(StorageFolder folder, string fi
             return await folder.CreateFileAsync(fileName, option);
         }
 
+        public static async Task<StorageFile> CreateFile(string filePath)
+        {
+            try
+            {
+                if (!string.IsNullOrEmpty(filePath))
+                {
+                    var pos = filePath.IndexOf(Path.DirectorySeparatorChar, 2);
+                    return await CreateFile(await StorageFolder.GetFolderFromPathAsync(filePath.Substring(0, pos)), filePath.Substring(pos + 1));
+                }
+            }
+            catch (Exception) { }
+
+            _lastErrorFileOpenPath = string.Empty;
+            return null;
+        }
+
+        public static string GetLastErrorFileOpenPath()
+        {
+            return _lastErrorFileOpenPath;
+        }
+
         public static async Task<bool> FileExists(StorageFile file)
         {
             try

src/Notepads/Views/MainPage/NotepadsMainPage.IO.cs

@@ -293,5 +293,29 @@ private static bool HaveNonemptyTextEditor(ITextEditor[] textEditors)
             }
             return false;
         }
+
+        public async Task CreateAndOpenFile()
+        {
+            if (!(FileSystemUtility.GetLastErrorFileOpenPath() is string lastErrorFileOpenPath) || string.IsNullOrEmpty(lastErrorFileOpenPath)) return;
+
+            bool createFile = false;
+            var createNewFileReminderDialog = new FileCreateDialog(lastErrorFileOpenPath, () =>
+            {
+                createFile = true;
+            });
+
+            await DialogManager.OpenDialogAsync(createNewFileReminderDialog, awaitPreviousDialog: true);
+
+            var file = await FileSystemUtility.CreateFile(createFile ? lastErrorFileOpenPath : string.Empty);
+
+            if (file != null)
+            {
+                await OpenFile(file);
+            }
+            else if (createFile)
+            {
+                NotificationCenter.Instance.PostNotification(string.Format(_resourceLoader.GetString("GetFileOpenCreateNewFileReminderDialog_NotificationMsg_FileCreateError"), lastErrorFileOpenPath), 1500);
+            }
+        }
     }
 }

src/Notepads/Views/MainPage/NotepadsMainPage.xaml.cs

@@ -224,9 +224,9 @@ private async void Sets_Loaded(object sender, RoutedEventArgs e)
                 if (file != null && await OpenFile(file))
                 {
                     loadedCount++;
+                    _appLaunchCmdDir = null;
+                    _appLaunchCmdArgs = null;
                 }
-                _appLaunchCmdDir = null;
-                _appLaunchCmdArgs = null;
             }
             else if (_appLaunchUri != null)
             {
@@ -274,6 +274,17 @@ private async void Sets_Loaded(object sender, RoutedEventArgs e)
                 Window.Current.CoreWindow.Activated -= CoreWindow_Activated;
                 Window.Current.CoreWindow.Activated += CoreWindow_Activated;
             }
+            Window.Current.CoreWindow.Activated -= CoreWindow_Activated;
+            Window.Current.CoreWindow.Activated += CoreWindow_Activated;
+            Application.Current.EnteredBackground -= App_EnteredBackground;
+            Application.Current.EnteredBackground += App_EnteredBackground;
+
+            if (_appLaunchCmdDir != null)
+            {
+                await CreateAndOpenFile();
+                _appLaunchCmdDir = null;
+                _appLaunchCmdArgs = null;
+            }
         }
 
         private async void App_EnteredBackground(object sender, Windows.ApplicationModel.EnteredBackgroundEventArgs e)