Support custom command implementations

src/MvvmGen.SourceGenerators.Tests/Model/ViewModelToGenerateTests.cs

@@ -375,6 +375,22 @@ public void ShouldBeEqual8()
             Assert.Equal(_viewModelToGenerate1, _viewModelToGenerate2);
         }
 
+        [Fact]
+        public void ShouldNotBeEqualDifferentCommandType()
+        {
+            _viewModelToGenerate2.CommandType = "MyCommand";
+
+            Assert.NotEqual(_viewModelToGenerate1, _viewModelToGenerate2);
+        }
+
+        [Fact]
+        public void ShouldBeEqual9()
+        {
+            _viewModelToGenerate1.CommandType = "DelegateCommand";
+
+            Assert.Equal(_viewModelToGenerate1, _viewModelToGenerate2);
+        }
+
         private static void FillAllProperties(ViewModelToGenerate viewModelToGenerate)
         {
             viewModelToGenerate.ClassAccessModifier = "public";

src/MvvmGen.SourceGenerators.Tests/ViewModelGeneratorTests/CommandAttributeTests.cs

@@ -174,5 +174,62 @@ public EmployeeViewModel()
 }}
 ");
         }
+
+        [Fact]
+        public void GenerateCommandPropertyWithCustomCommandType()
+        {
+            ShouldGenerateExpectedCode(
+      @"using MvvmGen;
+
+namespace MyCode
+{
+  public class MyCommand : IDelegateCommand
+  {
+    private readonly Action<object?> _execute;
+    private readonly Func<object?, bool>? _canExecute;
+
+    public MyCommand(Action<object?> execute, Func<object?, bool>? canExecute = null)
+    {
+      _execute = execute ?? throw new ArgumentNullException(nameof(execute));
+      _canExecute = canExecute;
+    }
+
+    public event EventHandler? CanExecuteChanged;
+
+    public void RaiseCanExecuteChanged() => CanExecuteChanged?.Invoke(this, EventArgs.Empty);
+
+    public void Execute(object? parameter) => _execute(parameter);
+
+    public bool CanExecute(object? parameter) => _canExecute == null || _canExecute(parameter);
+  }
+
+  [ViewModel(CommandType=typeof(MyCommand))]
+  public partial class EmployeeViewModel
+  {
+    [Command]
+    public void SaveAll() { }
+  }
+}",
+      $@"{AutoGeneratedTopContent}
+
+namespace MyCode
+{{
+    partial class EmployeeViewModel : global::MvvmGen.ViewModels.ViewModelBase
+    {{
+        private IDelegateCommand? _saveAllCommand;
+
+        public EmployeeViewModel()
+        {{
+            this.OnInitialize();
+        }}
+
+        partial void OnInitialize();
+
+        public IDelegateCommand SaveAllCommand => _saveAllCommand ??= new MyCode.MyCommand(_ => SaveAll());
+    }}
+}}
+");
+        }
+
     }
 }

src/MvvmGen.SourceGenerators/Generators/CommandPropertyGenerator.cs

@@ -11,14 +11,16 @@ namespace MvvmGen.Generators
 {
     internal static class CommandPropertyGenerator
     {
-        internal static void GenerateCommandProperties(this ViewModelBuilder vmBuilder, IEnumerable<CommandToGenerate>? commandsToGenerate)
+        internal static void GenerateCommandProperties(this ViewModelBuilder vmBuilder,
+            IEnumerable<CommandToGenerate>? commandsToGenerate,
+            string commandType)
         {
             if (commandsToGenerate is not null)
             {
                 foreach (var commandToGenerate in commandsToGenerate)
                 {
                     vmBuilder.AppendLineBeforeMember();
-                    vmBuilder.Append($"public IDelegateCommand {commandToGenerate.PropertyName} => {commandToGenerate.FieldName} ??= new DelegateCommand({GetMethodCall(commandToGenerate.ExecuteMethod)}");
+                    vmBuilder.Append($"public IDelegateCommand {commandToGenerate.PropertyName} => {commandToGenerate.FieldName} ??= new {commandType}({GetMethodCall(commandToGenerate.ExecuteMethod)}");
                     if (commandToGenerate.CanExecuteMethod is not null)
                     {
                         vmBuilder.Append($", {GetMethodCall(commandToGenerate.CanExecuteMethod)}");

src/MvvmGen.SourceGenerators/Inspectors/ViewModelAttributeInspector.cs

@@ -39,5 +39,20 @@
 
             return modelPropertyName;
         }
+
+        internal static string InspectCommandType(AttributeData viewModelAttributeData)
+        {
+            string commandType = "DelegateCommand";
+
+            foreach (var arg in viewModelAttributeData.NamedArguments)
+            {
+                if (arg.Key == "CommandType")
+                {
+                    commandType = arg.Value.Value?.ToString();
+                }
+            }
+
+            return commandType;
+        }
     }
 }

src/MvvmGen.SourceGenerators/Model/CommandToGenerate.cs

@@ -15,7 +15,7 @@ public CommandToGenerate(CommandMethod executeMethod, string propertyName)
         {
             ExecuteMethod = executeMethod;
             PropertyName = propertyName;
-            FieldName = $"_{PropertyName.Substring(0,1).ToLower()}{PropertyName.Substring(1)}";
+            FieldName = $"_{PropertyName.Substring(0, 1).ToLower()}{PropertyName.Substring(1)}";
         }
 
         public CommandMethod ExecuteMethod { get; }
@@ -26,6 +26,8 @@ public CommandToGenerate(CommandMethod executeMethod, string propertyName)
 
         public CommandMethod? CanExecuteMethod { get; set; }
 
+        public string CommandType { get; set; } = "DelegateCommand";
+
         public override bool Equals(object? obj)
         {
             return Equals(obj as CommandToGenerate);

src/MvvmGen.SourceGenerators/Model/ViewModelToGenerate.cs

@@ -37,6 +37,8 @@ public ViewModelToGenerate(string className, string namespaceName)
 
         public bool InheritFromViewModelBase { get; set; }
 
+        public string CommandType { get; set; } = "DelegateCommand";
+
         public IEnumerable<CommandToGenerate>? CommandsToGenerate { get; set; }
 
         public IEnumerable<CommandInvalidationToGenerate>? CommandInvalidationsToGenerate { get; set; }
@@ -66,6 +68,7 @@ public bool Equals(ViewModelToGenerate? other)
                    WrappedModelPropertyName == other.WrappedModelPropertyName &&
                    IsEventSubscriber == other.IsEventSubscriber &&
                    GenerateConstructor == other.GenerateConstructor &&
+                   CommandType== other.CommandType &&
                    InheritFromViewModelBase == other.InheritFromViewModelBase &&
                    EqualityComparer<FactoryToGenerate?>.Default.Equals(ViewModelFactoryToGenerate, other.ViewModelFactoryToGenerate) &&
                    EqualityComparer<InterfaceToGenerate?>.Default.Equals(ViewModelInterfaceToGenerate, other.ViewModelInterfaceToGenerate) &&

src/MvvmGen.SourceGenerators/ViewModelGenerator.cs

@@ -21,7 +21,7 @@
     /// Generates ViewModels for classes that are decorated with the MvvmGen.ViewModelAttribute.
     /// </summary>
     [Generator]
     public class ViewModelGenerator : IIncrementalGenerator
     {
         private static readonly string _versionString;
 
@@ -81,7 +81,8 @@
             {
                 ClassAccessModifier = accessModifier,
                 InjectionsToGenerate = ViewModelInjectAttributeInspector.Inspect(viewModelClassSymbol),
-                BaseClassInjectionsToGenerate=ViewModelInjectAttributeInspector.Inspect(viewModelClassSymbol.BaseType),
+                BaseClassInjectionsToGenerate = ViewModelInjectAttributeInspector.Inspect(viewModelClassSymbol.BaseType),
+                CommandType = ViewModelAttributeInspector.InspectCommandType(viewModelAttributeData),
                 GenerateConstructor = ViewModelAttributeInspector.InspectGenerateConstructor(viewModelAttributeData),
                 ViewModelFactoryToGenerate = ViewModelGenerateFactoryAttributeInspector.Inspect(viewModelClassSymbol),
                 InheritFromViewModelBase = ViewModelBaseClassInspector.Inspect(viewModelClassSymbol, viewModelBaseClassSymbol),
@@ -91,7 +92,7 @@
             };
 
             viewModelToGenerate.WrappedModelPropertyName = ViewModelAttributeInspector.InspectModelPropertyName(viewModelAttributeData);
-            viewModelToGenerate.WrappedModelType = ModelMemberInspector.Inspect(viewModelAttributeData, viewModelToGenerate.PropertiesToGenerate,viewModelToGenerate.WrappedModelPropertyName);
+            viewModelToGenerate.WrappedModelType = ModelMemberInspector.Inspect(viewModelAttributeData, viewModelToGenerate.PropertiesToGenerate, viewModelToGenerate.WrappedModelPropertyName);
 
             viewModelToGenerate.ViewModelInterfaceToGenerate = ViewModelGenerateInterfaceAttributeInspector.Inspect(viewModelClassSymbol,
                 viewModelToGenerate.PropertiesToGenerate, viewModelToGenerate.CommandsToGenerate, context.Node.SyntaxTree);
@@ -142,11 +143,11 @@
 
             vmBuilder.GenerateConstructor(viewModelToGenerate);
 
-            vmBuilder.GenerateCommandProperties(viewModelToGenerate.CommandsToGenerate);
+            vmBuilder.GenerateCommandProperties(viewModelToGenerate.CommandsToGenerate, viewModelToGenerate.CommandType);
 
             vmBuilder.GenerateProperties(viewModelToGenerate.PropertiesToGenerate);
 
-            vmBuilder.GenerateModelProperty(viewModelToGenerate.WrappedModelType,viewModelToGenerate.WrappedModelPropertyName);
+            vmBuilder.GenerateModelProperty(viewModelToGenerate.WrappedModelType, viewModelToGenerate.WrappedModelPropertyName);
 
             vmBuilder.GenerateInjectionProperties(viewModelToGenerate.InjectionsToGenerate);
 

src/MvvmGen/Attributes/ViewModelAttribute.cs

@@ -44,5 +44,19 @@ public ViewModelAttribute(Type modelType)
         /// Gets or sets if a constructor is generated. Default value is true.
         /// </summary>
         public bool GenerateConstructor { get; set; } = true;
+
+        /// <summary>
+        /// Gets or sets the <see cref="MvvmGen.Commands.IDelegateCommand"/> implementation to use.
+        /// That your <see cref="MvvmGen.Commands.IDelegateCommand"/> implementation works seemlessly 
+        /// with MvvmGen, it must have a constructor with the following signature:
+        /// <code>
+        /// public YourCommand(Action<object?> execute, Func<object?, bool>? canExecute = null)
+        /// {
+        /// }  
+        /// </code>
+        /// If this property is not set, the <see cref="MvvmGen.Commands.DelegateCommand"/> class is used
+        /// as an <see cref="MvvmGen.Commands.IDelegateCommand"/> implementation.
+        /// </summary>
+        public Type? CommandType { get; set; }
     }
 }