From 6ba9c57bd0493b13922882faf1912a6aebb6d011 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Holger=20B=C3=B6rchers?= <holger@boerchers.org>
Date: Tue, 18 Feb 2020 22:07:39 +0100
Subject: [PATCH] persisting view models

---
 BaseViewModel.cs   | 66 +++++++++++++++++++++++++++++++++++++++++-----
 MainWindow.xaml    | 43 +++++++++++++++++++++++++-----
 WindowViewModel.cs |  9 +++++++
 3 files changed, 104 insertions(+), 14 deletions(-)

diff --git a/BaseViewModel.cs b/BaseViewModel.cs
index 1f4038c..741fcd4 100644
--- a/BaseViewModel.cs
+++ b/BaseViewModel.cs
@@ -1,6 +1,8 @@
-using System.Collections.Generic;
+using System;
+using System.Collections.Generic;
 using System.ComponentModel;
 using System.IO;
+using System.Reflection;
 using System.Runtime.CompilerServices;
 using System.Text.Json;
 using System.Windows;
@@ -11,7 +13,13 @@ namespace ModernWpfPlayground
 {
     public abstract class BaseViewModel : INotifyPropertyChanged
     {
+        protected BaseViewModel()
+        {
+            _properties = GetType().GetProperties();
+        }
+
         private readonly Dictionary<string, object> _valueDict = new Dictionary<string, object>();
+        private readonly PropertyInfo[] _properties;
 
         protected bool SetProperty<T>(T value, [CallerMemberName] string propertyName = null)
         {
@@ -39,7 +47,7 @@ namespace ModernWpfPlayground
         public void SaveViewModel()
         {
             var contents = JsonSerializer.Serialize(_valueDict);
-            var saveFileDialog = new SaveFileDialog();
+            var saveFileDialog = new SaveFileDialog {AddExtension = true, DefaultExt = "*.json"};
             var result = saveFileDialog.ShowDialog(Application.Current.MainWindow?.Owner);
             if (result == true)
             {
@@ -47,15 +55,59 @@ namespace ModernWpfPlayground
             }
         }
 
-        public void LoadViewModel(string path)
+        public void ResetViewModel()
         {
-            var contents = File.ReadAllText(path);
-            var obj = JsonSerializer.Deserialize<Dictionary<string, object>>(contents);
-            foreach (var (key, value) in obj)
+            foreach (var key in _valueDict.Keys)
             {
-                _valueDict[key] = value;
+                _valueDict.Remove(key);
                 OnPropertyChanged(key);
             }
         }
+
+        public void LoadViewModel()
+        {
+            var openFileDialog = new OpenFileDialog {AddExtension = true, DefaultExt = "*.json"};
+            var result = openFileDialog.ShowDialog(Application.Current.MainWindow?.Owner);
+            if (result != true) return;
+            var contents = File.ReadAllText(openFileDialog.FileName);
+            var obj = JsonSerializer.Deserialize<Dictionary<string, JsonElement>>(contents);
+            foreach (var (key, value) in obj)
+            {
+                _valueDict[key] = CastToType(key, value);
+                OnPropertyChanged(key);
+            }
+        }
+
+        private object CastToType(string key, JsonElement value)
+        {
+
+            var property = Array.Find(_properties, x => x.Name == key);
+            if (property.PropertyType == typeof(double))
+            {
+                return value.GetDouble();
+            }
+
+            if (property.PropertyType == typeof(bool))
+            {
+                return value.GetBoolean();
+            }
+
+            if (property.PropertyType == typeof(int))
+            {
+                return value.GetInt32();
+            }
+
+            if (property.PropertyType.IsEnum)
+            {
+                return Enum.ToObject(property.PropertyType, value.GetInt32());
+            }
+
+            if (property.PropertyType == typeof(string))
+            {
+                return value.GetString();
+            }
+
+            return default;
+        }
     }
 }
\ No newline at end of file
diff --git a/MainWindow.xaml b/MainWindow.xaml
index a60c3f2..ea7cb01 100644
--- a/MainWindow.xaml
+++ b/MainWindow.xaml
@@ -22,6 +22,21 @@
     <Window.Resources>
         <local:PixelsToGridLengthConverter x:Key="PixelsToGridLength" />
     </Window.Resources>
+    <Window.InputBindings>
+        <KeyBinding
+            Key="O"
+            Command="{Binding OpenViewModelCommand}"
+            Modifiers="Control" />
+        <KeyBinding
+            Key="S"
+            Command="{Binding SaveViewModelCommand}"
+            Modifiers="Control" />
+        <KeyBinding
+            Key="N"
+            Command="{Binding ResetViewModelCommand}"
+            Modifiers="Control" />
+    </Window.InputBindings>
+
     <DockPanel>
         <!--  TitleBar  -->
         <Grid
@@ -63,8 +78,18 @@
                     </Style>
                 </Menu.Resources>
                 <MenuItem Header="File">
-                    <MenuItem Header="New" />
-                    <MenuItem Header="Open" />
+                    <MenuItem
+                        Command="{Binding ResetViewModelCommand}"
+                        Header="New"
+                        InputGestureText="Ctrl+N" />
+                    <MenuItem
+                        Command="{Binding OpenViewModelCommand}"
+                        Header="Open"
+                        InputGestureText="Ctrl+O" />
+                    <MenuItem
+                        Command="{Binding SaveViewModelCommand}"
+                        Header="Save"
+                        InputGestureText="Ctrl+S" />
                     <Separator />
                     <MenuItem Command="{Binding CloseCommand}" Header="Close" />
                 </MenuItem>
@@ -172,14 +197,18 @@
                             Margin="5"
                             Orientation="Vertical"
                             Spacing="5">
-                            <Button HorizontalAlignment="Stretch" Content="New" />
-                            <Button HorizontalAlignment="Stretch" Content="Open" />
-                            <Separator />
-                            <Button HorizontalAlignment="Stretch" Content="Open catalog" />
+                            <Button
+                                HorizontalAlignment="Stretch"
+                                Command="{Binding OpenViewModelCommand}"
+                                Content="Open" />
+                            <Button
+                                HorizontalAlignment="Stretch"
+                                Command="{Binding SaveViewModelCommand}"
+                                Content="Save" />
                         </ui:SimpleStackPanel>
                     </Grid>
                 </TabItem>
-                <TabItem Header="General">
+                <TabItem Header="General" IsSelected="True">
                     <ui:SimpleStackPanel Margin="5" Spacing="10">
                         <controls:PropertyPresenter2
                             Command="{Binding ShowDialogCommand}"
diff --git a/WindowViewModel.cs b/WindowViewModel.cs
index 7213d9f..bc8e49d 100644
--- a/WindowViewModel.cs
+++ b/WindowViewModel.cs
@@ -10,6 +10,9 @@ namespace ModernWpfPlayground
         {
             ShowDialogCommand = new RelayCommand(async x => await ShowDialogAsync());
             CloseCommand = new RelayCommand(x => Application.Current.Shutdown());
+            OpenViewModelCommand = new RelayCommand(x => LoadViewModel());
+            SaveViewModelCommand = new RelayCommand(x => SaveViewModel());
+            ResetViewModelCommand = new RelayCommand(x => ResetViewModel());
         }
 
         private async Task ShowDialogAsync()
@@ -52,5 +55,11 @@ namespace ModernWpfPlayground
         }
 
         public ICommand CloseCommand { get; }
+
+        public ICommand OpenViewModelCommand { get; }
+
+        public ICommand SaveViewModelCommand { get; }
+
+        public ICommand ResetViewModelCommand { get; }
     }
 }
\ No newline at end of file