Wire up the "add" button in the channel mapping list

Author: jskeet

DigiMixer/DigiMixer.Wpf/ChannelListControl.xaml

@@ -14,7 +14,7 @@
                             MinHeight="50" MaxHeight="205" Margin="5" PreviewKeyDown="HandleKeyDown" x:Name="mappingList" />
             </Border>
             <DockPanel Width="260" Margin="0,5,0,0">
-                <Button DockPanel.Dock="Left" Content="Add" HorizontalAlignment="Left" VerticalAlignment="Top"/>
+                <Button DockPanel.Dock="Left" Content="Add" Command="{Binding AddChannelCommand}" HorizontalAlignment="Left" VerticalAlignment="Top"/>
                 <TextBlock Margin="5,0,0,0" DockPanel.Dock="Right" HorizontalAlignment="Left" TextWrapping="Wrap">Use Ctrl-Up and Ctrl-Down to move the selected item, or Ctrl-Del to delete it.</TextBlock>
             </DockPanel>
         </StackPanel>

DigiMixer/DigiMixer.Wpf/ChannelListViewModel.cs

@@ -1,20 +1,58 @@
-using JonSkeet.WpfUtil;
+using DigiMixer.Controls;
+using JonSkeet.WpfUtil;
 using System.Collections.ObjectModel;
+using System.Windows.Input;
 
 namespace DigiMixer.Wpf;
 
 public class ChannelListViewModel : ViewModelBase, IReorderableList
 {
+    private readonly 
+        string idPrefix;
     public ObservableCollection<ChannelMappingViewModel> Mappings { get; } = new();
 
+    public ICommand AddChannelCommand { get; }
+
     private ChannelMappingViewModel selectedMapping;
     public ChannelMappingViewModel SelectedMapping
     {
         get => selectedMapping;
         set => SetProperty(ref selectedMapping, value);
     }
 
+    public ChannelListViewModel(string idPrefix)
+    {
+        AddChannelCommand = ActionCommand.FromAction(AddChannel);
+        this.idPrefix = idPrefix;
+    }
+
     public void DeleteSelectedItem() => SelectedMapping = Mappings.RemoveSelected(SelectedMapping);
     public void MoveSelectedItemUp() => Mappings.MoveSelectedItemUp(SelectedMapping, value => SelectedMapping = value);
     public void MoveSelectedItemDown() => Mappings.MoveSelectedItemDown(SelectedMapping, value => SelectedMapping = value);
+
+    private void AddChannel()
+    {
+        // Generate an ID that's unused and somewhat plausible.
+        int index = Mappings.Count + 1;
+        while (Mappings.Any(m => m.Model.Id == $"{idPrefix}{index}"))
+        {
+            index++;
+        }
+        string id = $"{idPrefix}{index}";
+        // Find the first unused channel number
+        int channel = 1;
+        while (Mappings.Any(m => m.Number == channel))
+        {
+            channel++;
+        }
+        var mapping = new ChannelMappingViewModel(new ChannelMapping
+        {
+            Id = $"{idPrefix}{index}",
+            DisplayName = "Unnamed channel",
+            Channel = channel,
+            InitiallyVisible = true
+        });
+        Mappings.Add(mapping);
+        SelectedMapping = mapping;
+    }
 }

DigiMixer/DigiMixer.Wpf/ConfigurationEditorViewModel.cs

@@ -10,6 +10,8 @@ namespace DigiMixer.Wpf;
 
 public class ConfigurationEditorViewModel : ViewModelBase<DigiMixerAppConfig>
 {
+    private const string InputPrefix = "input-";
+    private const string OutputPrefix = "output-";
     private readonly ILogger logger;
 
     private static List<(string, MHT)> allMixerTypes = new()
@@ -61,8 +63,8 @@ public string IconXPlusDevice
         set => SetProperty(IconXPlusDevice, value, x => Model.Mixer.IconXPlusDevice = x);
     }
 
-    public ChannelListViewModel InputChannels { get; } = new();
-    public ChannelListViewModel OutputChannels { get; } = new();
+    public ChannelListViewModel InputChannels { get; } = new(InputPrefix);
+    public ChannelListViewModel OutputChannels { get; } = new(OutputPrefix);
 
     public List<string> AllMixerTypes => allMixerTypes.Select(pair => pair.Item1).ToList();
 
@@ -135,7 +137,7 @@ private async Task TestConfiguration()
         {
             var inputMappings = inputs.Select((input, index) => new ChannelMappingViewModel(new ChannelMapping
             {
-                Id = $"input-{index + 1}",
+                Id = $"{InputPrefix}{index + 1}",
                 DisplayName = input.Name,
                 Channel = input.LeftOrMonoChannelId.Value,
                 InitiallyVisible = true
@@ -144,7 +146,7 @@ private async Task TestConfiguration()
 
             var outputMappings = outputs.Select((output, index) => new ChannelMappingViewModel(new ChannelMapping
             {
-                Id = $"output-{index + 1}",
+                Id = $"{OutputPrefix}{index + 1}",
                 DisplayName = output.Name,
                 Channel = output.LeftOrMonoChannelId.Value,
                 InitiallyVisible = true