Fix #4

Author: ChebanovDD

src/UnityMvvmToolkit.UnityPackage/Assets/Plugins/UnityMvvmToolkit/Runtime/External/UniTask/AsyncCommand.T.cs

@@ -18,6 +18,11 @@ public AsyncCommand(Func<T, CancellationToken, UniTask> action, Func<bool> canEx
 
         public void Execute(T parameter)
         {
+            if (IsRunning && AllowConcurrency == false)
+            {
+                return;
+            }
+
             ExecuteAsync(parameter).Forget();
         }
 

src/UnityMvvmToolkit.UnityPackage/Assets/Plugins/UnityMvvmToolkit/Runtime/External/UniTask/AsyncCommand.cs

@@ -18,6 +18,11 @@ public AsyncCommand(Func<CancellationToken, UniTask> action, Func<bool> canExecu
 
         public void Execute()
         {
+            if (IsRunning && AllowConcurrency == false)
+            {
+                return;
+            }
+
             ExecuteAsync().Forget();
         }
 

src/UnityMvvmToolkit.UnityPackage/Assets/Plugins/UnityMvvmToolkit/Runtime/External/UniTask/AsyncLazyCommand.T.cs

@@ -5,6 +5,7 @@ namespace UnityMvvmToolkit.UniTask
     using Core;
     using System;
     using Interfaces;
+    using Extensions;
     using System.Runtime.CompilerServices;
 
     public abstract class BaseAsyncCommand : BaseCommand, IBaseAsyncCommand
@@ -25,6 +26,8 @@ protected set
             }
         }
 
+        public bool AllowConcurrency { get; set; }
+
         public virtual bool DisableOnExecution { get; set; }
 
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
@@ -40,6 +43,8 @@ public override bool CanExecute()
 
         public virtual void Cancel()
         {
+            throw new InvalidOperationException(
+                $"To make the 'AsyncCommand' cancelable, use '{nameof(AsyncCommandExtensions.WithCancellation)}' extension.");
         }
     }
 }

src/UnityMvvmToolkit.UnityPackage/Assets/Plugins/UnityMvvmToolkit/Runtime/External/UniTask/AsyncLazyCommand.T.cs.meta

@@ -15,7 +15,9 @@ public static IAsyncCommand WithCancellation(this IAsyncCommand asyncCommand)
                 throw new NullReferenceException(nameof(asyncCommand));
             }
 
-            return new AsyncCommandWithCancellation(asyncCommand);
+            return asyncCommand.AllowConcurrency
+                ? new AsyncCommandWithCancellation(asyncCommand)
+                : new AsyncLazyCommandWithCancellation(asyncCommand);
         }
 
         public static IAsyncCommand<T> WithCancellation<T>(this IAsyncCommand<T> asyncCommand)
@@ -25,7 +27,9 @@ public static IAsyncCommand<T> WithCancellation<T>(this IAsyncCommand<T> asyncCo
                 throw new NullReferenceException(nameof(asyncCommand));
             }
 
-            return new AsyncCommandWithCancellation<T>(asyncCommand);
+            return asyncCommand.AllowConcurrency
+                ? new AsyncCommandWithCancellation<T>(asyncCommand)
+                : new AsyncLazyCommandWithCancellation<T>(asyncCommand);
         }
     }
 }