Replaced DependencyMap with ServiceCollection and IServiceProvider (#625)

src/Discord.Net.Commands/Attributes/ParameterPreconditionAttribute.cs

@@ -1,11 +1,12 @@
 using System;
 using System.Threading.Tasks;
+using Microsoft.Extensions.DependencyInjection;
 
 namespace Discord.Commands
 {
     [AttributeUsage(AttributeTargets.Parameter, AllowMultiple = true, Inherited = true)]
     public abstract class ParameterPreconditionAttribute : Attribute
     {
-        public abstract Task<PreconditionResult> CheckPermissions(ICommandContext context, ParameterInfo parameter, object value, IDependencyMap map);
+        public abstract Task<PreconditionResult> CheckPermissions(ICommandContext context, ParameterInfo parameter, object value, IServiceProvider services);
     }
 }

src/Discord.Net.Commands/Attributes/PreconditionAttribute.cs

@@ -6,6 +6,6 @@ namespace Discord.Commands
     [AttributeUsage(AttributeTargets.Method | AttributeTargets.Class, AllowMultiple = true, Inherited = true)]
     public abstract class PreconditionAttribute : Attribute
     {
-        public abstract Task<PreconditionResult> CheckPermissions(ICommandContext context, CommandInfo command, IDependencyMap map);
+        public abstract Task<PreconditionResult> CheckPermissions(ICommandContext context, CommandInfo command, IServiceProvider services);
     }
 }

src/Discord.Net.Commands/Attributes/Preconditions/RequireBotPermissionAttribute.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Threading.Tasks;
+using Microsoft.Extensions.DependencyInjection;
 
 namespace Discord.Commands
 {
@@ -41,7 +42,7 @@ namespace Discord.Commands
             GuildPermission = null;
         }
 
-        public override async Task<PreconditionResult> CheckPermissions(ICommandContext context, CommandInfo command, IDependencyMap map)
+        public override async Task<PreconditionResult> CheckPermissions(ICommandContext context, CommandInfo command, IServiceProvider services)
         {
             var guildUser = await context.Guild.GetCurrentUserAsync();
 

src/Discord.Net.Commands/Attributes/Preconditions/RequireContextAttribute.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Threading.Tasks;
+using Microsoft.Extensions.DependencyInjection;
 
 namespace Discord.Commands
 {
@@ -37,7 +38,7 @@ namespace Discord.Commands
             Contexts = contexts;
         }
 
-        public override Task<PreconditionResult> CheckPermissions(ICommandContext context, CommandInfo command, IDependencyMap map)
+        public override Task<PreconditionResult> CheckPermissions(ICommandContext context, CommandInfo command, IServiceProvider services)
         {
             bool isValid = false;
 

src/Discord.Net.Commands/Attributes/Preconditions/RequireOwnerAttribute.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Threading.Tasks;
+using Microsoft.Extensions.DependencyInjection;
 
 namespace Discord.Commands
 {
@@ -10,7 +11,7 @@ namespace Discord.Commands
     [AttributeUsage(AttributeTargets.Class | AttributeTargets.Method, AllowMultiple = false, Inherited = true)]
     public class RequireOwnerAttribute : PreconditionAttribute
     {
-        public override async Task<PreconditionResult> CheckPermissions(ICommandContext context, CommandInfo command, IDependencyMap map)
+        public override async Task<PreconditionResult> CheckPermissions(ICommandContext context, CommandInfo command, IServiceProvider services)
         {
             switch (context.Client.TokenType)
             {

src/Discord.Net.Commands/Attributes/Preconditions/RequireUserPermissionAttribute.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Threading.Tasks;
+using Microsoft.Extensions.DependencyInjection;
 
 namespace Discord.Commands
 {
@@ -42,7 +43,7 @@ namespace Discord.Commands
             GuildPermission = null;
         }
         
-        public override Task<PreconditionResult> CheckPermissions(ICommandContext context, CommandInfo command, IDependencyMap map)
+        public override Task<PreconditionResult> CheckPermissions(ICommandContext context, CommandInfo command, IServiceProvider services)
         {
             var guildUser = context.User as IGuildUser;
 

src/Discord.Net.Commands/Builders/CommandBuilder.cs

@@ -2,6 +2,7 @@
 using System.Linq;
 using System.Threading.Tasks;
 using System.Collections.Generic;
+using Microsoft.Extensions.DependencyInjection;
 
 namespace Discord.Commands.Builders
 {
@@ -12,7 +13,7 @@ namespace Discord.Commands.Builders
         private readonly List<string> _aliases;
 
         public ModuleBuilder Module { get; }
-        internal Func<ICommandContext, object[], IDependencyMap, Task> Callback { get; set; }
+        internal Func<ICommandContext, object[], IServiceProvider, Task> Callback { get; set; }
 
         public string Name { get; set; }
         public string Summary { get; set; }
@@ -35,7 +36,7 @@ namespace Discord.Commands.Builders
             _aliases = new List<string>();
         }
         //User-defined
-        internal CommandBuilder(ModuleBuilder module, string primaryAlias, Func<ICommandContext, object[], IDependencyMap, Task> callback)
+        internal CommandBuilder(ModuleBuilder module, string primaryAlias, Func<ICommandContext, object[], IServiceProvider, Task> callback)
             : this(module)
         {
             Discord.Preconditions.NotNull(primaryAlias, nameof(primaryAlias));

src/Discord.Net.Commands/Builders/ModuleBuilder.cs

@@ -1,6 +1,7 @@
 using System;
 using System.Collections.Generic;
 using System.Threading.Tasks;
+using Microsoft.Extensions.DependencyInjection;
 
 namespace Discord.Commands.Builders
 {
@@ -73,7 +74,7 @@ namespace Discord.Commands.Builders
             _preconditions.Add(precondition);
             return this;
         }
-        public ModuleBuilder AddCommand(string primaryAlias, Func<ICommandContext, object[], IDependencyMap, Task> callback, Action<CommandBuilder> createFunc)
+        public ModuleBuilder AddCommand(string primaryAlias, Func<ICommandContext, object[], IServiceProvider, Task> callback, Action<CommandBuilder> createFunc)
         {
             var builder = new CommandBuilder(this, primaryAlias, callback);
             createFunc(builder);

src/Discord.Net.Commands/Builders/ModuleClassBuilder.cs

@@ -243,7 +243,7 @@ namespace Discord.Commands
             }
 
             //We dont have a cached type reader, create one
-            reader = ReflectionUtils.CreateObject<TypeReader>(typeReaderType.GetTypeInfo(), service, DependencyMap.Empty);
+            reader = ReflectionUtils.CreateObject<TypeReader>(typeReaderType.GetTypeInfo(), service, EmptyServiceProvider.Instance);
             service.AddTypeReader(paramType, reader);
 
             return reader;

src/Discord.Net.Commands/CommandMatch.cs

@@ -1,5 +1,7 @@
-using System.Collections.Generic;
+using System;
+using System.Collections.Generic;
 using System.Threading.Tasks;
+using Microsoft.Extensions.DependencyInjection;
 
 namespace Discord.Commands
 {
@@ -14,13 +16,13 @@ namespace Discord.Commands
             Alias = alias;
         }
 
-        public Task<PreconditionResult> CheckPreconditionsAsync(ICommandContext context, IDependencyMap map = null)
-            => Command.CheckPreconditionsAsync(context, map);
+        public Task<PreconditionResult> CheckPreconditionsAsync(ICommandContext context, IServiceProvider services = null)
+            => Command.CheckPreconditionsAsync(context, services);
         public Task<ParseResult> ParseAsync(ICommandContext context, SearchResult searchResult, PreconditionResult? preconditionResult = null)
             => Command.ParseAsync(context, Alias.Length, searchResult, preconditionResult);
-        public Task<ExecuteResult> ExecuteAsync(ICommandContext context, IEnumerable<object> argList, IEnumerable<object> paramList, IDependencyMap map)
-            => Command.ExecuteAsync(context, argList, paramList, map);
-        public Task<ExecuteResult> ExecuteAsync(ICommandContext context, ParseResult parseResult, IDependencyMap map)
-            => Command.ExecuteAsync(context, parseResult, map);
+        public Task<ExecuteResult> ExecuteAsync(ICommandContext context, IEnumerable<object> argList, IEnumerable<object> paramList, IServiceProvider services)
+            => Command.ExecuteAsync(context, argList, paramList, services);
+        public Task<ExecuteResult> ExecuteAsync(ICommandContext context, ParseResult parseResult, IServiceProvider services)
+            => Command.ExecuteAsync(context, parseResult, services);
     }
 }

src/Discord.Net.Commands/CommandService.cs

@@ -8,6 +8,7 @@ using System.Linq;
 using System.Reflection;
 using System.Threading;
 using System.Threading.Tasks;
+using Microsoft.Extensions.DependencyInjection;
 
 namespace Discord.Commands
 {
@@ -247,11 +248,11 @@ namespace Discord.Commands
                 return SearchResult.FromError(CommandError.UnknownCommand, "Unknown command.");
         }
 
-        public Task<IResult> ExecuteAsync(ICommandContext context, int argPos, IDependencyMap dependencyMap = null, MultiMatchHandling multiMatchHandling = MultiMatchHandling.Exception)
-            => ExecuteAsync(context, context.Message.Content.Substring(argPos), dependencyMap, multiMatchHandling);
-        public async Task<IResult> ExecuteAsync(ICommandContext context, string input, IDependencyMap dependencyMap = null, MultiMatchHandling multiMatchHandling = MultiMatchHandling.Exception)
+        public Task<IResult> ExecuteAsync(ICommandContext context, int argPos, IServiceProvider services = null, MultiMatchHandling multiMatchHandling = MultiMatchHandling.Exception)
+            => ExecuteAsync(context, context.Message.Content.Substring(argPos), services, multiMatchHandling);
+        public async Task<IResult> ExecuteAsync(ICommandContext context, string input, IServiceProvider services = null, MultiMatchHandling multiMatchHandling = MultiMatchHandling.Exception)
         {
-            dependencyMap = dependencyMap ?? DependencyMap.Empty;
+            services = services ?? EmptyServiceProvider.Instance;
 
             var searchResult = Search(context, input);
             if (!searchResult.IsSuccess)
@@ -260,7 +261,7 @@ namespace Discord.Commands
             var commands = searchResult.Commands;
             for (int i = 0; i < commands.Count; i++)
             {
-                var preconditionResult = await commands[i].CheckPreconditionsAsync(context, dependencyMap).ConfigureAwait(false);
+                var preconditionResult = await commands[i].CheckPreconditionsAsync(context, services).ConfigureAwait(false);
                 if (!preconditionResult.IsSuccess)
                 {
                     if (commands.Count == 1)
@@ -294,10 +295,19 @@ namespace Discord.Commands
                     }
                 }
 
-                return await commands[i].ExecuteAsync(context, parseResult, dependencyMap).ConfigureAwait(false);
+                return await commands[i].ExecuteAsync(context, parseResult, services).ConfigureAwait(false);
             }
 
             return SearchResult.FromError(CommandError.UnknownCommand, "This input does not match any overload.");
         }
+
+        public ServiceCollection CreateServiceCollection()
+        {
+            var serviceCollection = new ServiceCollection();
+            serviceCollection.AddSingleton<CommandService>(this);
+            serviceCollection.AddSingleton<IServiceCollection>(serviceCollection);
+            serviceCollection.AddSingleton<ServiceCollection>(serviceCollection);
+            return serviceCollection;
+        }
     }
 }

src/Discord.Net.Commands/Dependencies/DependencyMap.cs

@@ -1,102 +0,0 @@
-using System;
-using System.Collections.Generic;
-using System.Linq;
-
-namespace Discord.Commands
-{
-    public class DependencyMap : IDependencyMap
-    {
-        private static readonly Type[] _typeBlacklist = new[] {
-            typeof(IDependencyMap),
-            typeof(CommandService)
-        };
-
-        private Dictionary<Type, Func<object>> map;
-
-        public static DependencyMap Empty => new DependencyMap();
-
-        public DependencyMap()
-        {
-            map = new Dictionary<Type, Func<object>>();
-        }
-
-        /// <inheritdoc />
-        public void Add<T>(T obj) where T : class 
-            => AddFactory(() => obj);
-        /// <inheritdoc />
-        public bool TryAdd<T>(T obj) where T : class
-            => TryAddFactory(() => obj);
-        /// <inheritdoc />
-        public void AddTransient<T>() where T : class, new() 
-            => AddFactory(() => new T());
-        /// <inheritdoc />
-        public bool TryAddTransient<T>() where T : class, new()
-            => TryAddFactory(() => new T());
-        /// <inheritdoc />
-        public void AddTransient<TKey, TImpl>() where TKey : class 
-            where TImpl : class, TKey, new() 
-            => AddFactory<TKey>(() => new TImpl());
-        public bool TryAddTransient<TKey, TImpl>() where TKey : class
-            where TImpl : class, TKey, new()
-            => TryAddFactory<TKey>(() => new TImpl());
-        
-        /// <inheritdoc />
-        public void AddFactory<T>(Func<T> factory) where T : class
-        {
-            if (!TryAddFactory(factory))
-                throw new InvalidOperationException($"The dependency map already contains \"{typeof(T).FullName}\"");
-        }
-        /// <inheritdoc />
-        public bool TryAddFactory<T>(Func<T> factory) where T : class
-        {
-            var type = typeof(T);
-            if (_typeBlacklist.Contains(type) || map.ContainsKey(type))
-                return false;
-            map.Add(type, factory);
-            return true;
-        }
-
-        /// <inheritdoc />
-        public T Get<T>() where T : class
-        {
-            return (T)Get(typeof(T));
-        }
-        /// <inheritdoc />
-        public object Get(Type t)
-        {
-            object result;
-            if (!TryGet(t, out result))
-                throw new KeyNotFoundException($"The dependency map does not contain \"{t.FullName}\"");
-            else
-                return result;
-        }
-
-        /// <inheritdoc />
-        public bool TryGet<T>(out T result) where T : class
-        {
-            object untypedResult;
-            if (TryGet(typeof(T), out untypedResult))
-            {
-                result = (T)untypedResult;
-                return true;
-            }
-            else
-            {
-                result = default(T);
-                return false;
-            }
-        }
-        /// <inheritdoc />
-        public bool TryGet(Type t, out object result)
-        {
-            Func<object> func;
-            if (map.TryGetValue(t, out func))
-            {
-                result = func();
-                return true;
-            }
-            result = null;
-            return false;
-        }
-    }
-}

src/Discord.Net.Commands/Dependencies/IDependencyMap.cs

@@ -1,89 +0,0 @@
-using System;
-
-namespace Discord.Commands
-{
-    public interface IDependencyMap
-    {
-        /// <summary>
-        /// Add an instance of a service to be injected.
-        /// </summary>
-        /// <typeparam name="T">The type of service.</typeparam>
-        /// <param name="obj">The instance of a service.</param>
-        void Add<T>(T obj) where T : class;
-        /// <summary>
-        /// Tries to add an instance of a service to be injected.
-        /// </summary>
-        /// <typeparam name="T">The type of service.</typeparam>
-        /// <param name="obj">The instance of a service.</param>
-        /// <returns>A bool, indicating if the service was successfully added to the DependencyMap.</returns>
-        bool TryAdd<T>(T obj) where T : class;
-        /// <summary>
-        /// Add a service that will be injected by a new instance every time.
-        /// </summary>
-        /// <typeparam name="T">The type of instance to inject.</typeparam>
-        void AddTransient<T>() where T : class, new();
-        /// <summary>
-        /// Tries to add a service that will be injected by a new instance every time.
-        /// </summary>
-        /// <typeparam name="T">The type of instance to inject.</typeparam>
-        /// <returns>A bool, indicating if the service was successfully added to the DependencyMap.</returns>
-        bool TryAddTransient<T>() where T : class, new();
-        /// <summary>
-        /// Add a service that will be injected by a new instance every time.
-        /// </summary>
-        /// <typeparam name="TKey">The type to look for when injecting.</typeparam>
-        /// <typeparam name="TImpl">The type to inject when injecting.</typeparam>
-        /// <example>
-        /// map.AddTransient&#60;IService, Service&#62;
-        /// </example>
-        void AddTransient<TKey, TImpl>() where TKey: class where TImpl : class, TKey, new();
-        /// <summary>
-        /// Tries to add a service that will be injected by a new instance every time.
-        /// </summary>
-        /// <typeparam name="TKey">The type to look for when injecting.</typeparam>
-        /// <typeparam name="TImpl">The type to inject when injecting.</typeparam>
-        /// <returns>A bool, indicating if the service was successfully added to the DependencyMap.</returns>
-        bool TryAddTransient<TKey, TImpl>() where TKey : class where TImpl : class, TKey, new();
-        /// <summary>
-        /// Add a service that will be injected by a factory.
-        /// </summary>
-        /// <typeparam name="T">The type to look for when injecting.</typeparam>
-        /// <param name="factory">The factory that returns a type of this service.</param>
-        void AddFactory<T>(Func<T> factory) where T : class;
-        /// <summary>
-        /// Tries to add a service that will be injected by a factory.
-        /// </summary>
-        /// <typeparam name="T">The type to look for when injecting.</typeparam>
-        /// <param name="factory">The factory that returns a type of this service.</param>
-        /// <returns>A bool, indicating if the service was successfully added to the DependencyMap.</returns>
-        bool TryAddFactory<T>(Func<T> factory) where T : class;
-
-        /// <summary>
-        /// Pull an object from the map.
-        /// </summary>
-        /// <typeparam name="T">The type of service.</typeparam>
-        /// <returns>An instance of this service.</returns>
-        T Get<T>() where T : class;
-        /// <summary>
-        /// Try to pull an object from the map.
-        /// </summary>
-        /// <typeparam name="T">The type of service.</typeparam>
-        /// <param name="result">The instance of this service.</param>
-        /// <returns>Whether or not this object could be found in the map.</returns>
-        bool TryGet<T>(out T result) where T : class;
-
-        /// <summary>
-        /// Pull an object from the map.
-        /// </summary>
-        /// <param name="t">The type of service.</param>
-        /// <returns>An instance of this service.</returns>
-        object Get(Type t);
-        /// <summary>
-        /// Try to pull an object from the map.
-        /// </summary>
-        /// <param name="t">The type of service.</param>
-        /// <param name="result">An instance of this service.</param>
-        /// <returns>Whether or not this object could be found in the map.</returns>
-        bool TryGet(Type t, out object result);
-    }
-}

src/Discord.Net.Commands/Discord.Net.Commands.csproj

@@ -9,4 +9,7 @@
   <ItemGroup>
     <ProjectReference Include="..\Discord.Net.Core\Discord.Net.Core.csproj" />
   </ItemGroup>
+  <ItemGroup>
+    <PackageReference Include="Microsoft.Extensions.DependencyInjection" Version="1.1.0" />
+  </ItemGroup>
 </Project>

src/Discord.Net.Commands/EmptyServiceProvider.cs

@@ -0,0 +1,11 @@
+using System;
+
+namespace Discord.Commands
+{
+    internal class EmptyServiceProvider : IServiceProvider
+    {
+        public static readonly EmptyServiceProvider Instance = new EmptyServiceProvider();
+        
+        public object GetService(Type serviceType) => null;
+    }
+}

src/Discord.Net.Commands/Info/CommandInfo.cs

@@ -8,6 +8,7 @@ using System.Linq;
 using System.Reflection;
 using System.Runtime.ExceptionServices;
 using System.Threading.Tasks;
+using Microsoft.Extensions.DependencyInjection;
 
 namespace Discord.Commands
 {
@@ -17,7 +18,7 @@ namespace Discord.Commands
         private static readonly System.Reflection.MethodInfo _convertParamsMethod = typeof(CommandInfo).GetTypeInfo().GetDeclaredMethod(nameof(ConvertParamsList));
         private static readonly ConcurrentDictionary<Type, Func<IEnumerable<object>, object>> _arrayConverters = new ConcurrentDictionary<Type, Func<IEnumerable<object>, object>>();
 
-        private readonly Func<ICommandContext, object[], IDependencyMap, Task> _action;
+        private readonly Func<ICommandContext, object[], IServiceProvider, Task> _action;
 
         public ModuleInfo Module { get; }
         public string Name { get; }
@@ -63,21 +64,20 @@ namespace Discord.Commands
             _action = builder.Callback;
         }
 
-        public async Task<PreconditionResult> CheckPreconditionsAsync(ICommandContext context, IDependencyMap map = null)
+        public async Task<PreconditionResult> CheckPreconditionsAsync(ICommandContext context, IServiceProvider services = null)
         {
-            if (map == null)
-                map = DependencyMap.Empty;
+            services = services ?? EmptyServiceProvider.Instance;
 
             foreach (PreconditionAttribute precondition in Module.Preconditions)
             {
-                var result = await precondition.CheckPermissions(context, this, map).ConfigureAwait(false);
+                var result = await precondition.CheckPermissions(context, this, services).ConfigureAwait(false);
                 if (!result.IsSuccess)
                     return result;
             }
 
             foreach (PreconditionAttribute precondition in Preconditions)
             {
-                var result = await precondition.CheckPermissions(context, this, map).ConfigureAwait(false);
+                var result = await precondition.CheckPermissions(context, this, services).ConfigureAwait(false);
                 if (!result.IsSuccess)
                     return result;
             }
@@ -96,7 +96,7 @@ namespace Discord.Commands
             return await CommandParser.ParseArgs(this, context, input, 0).ConfigureAwait(false);
         }
 
-        public Task<ExecuteResult> ExecuteAsync(ICommandContext context, ParseResult parseResult, IDependencyMap map)
+        public Task<ExecuteResult> ExecuteAsync(ICommandContext context, ParseResult parseResult, IServiceProvider services)
         {
             if (!parseResult.IsSuccess)
                 return Task.FromResult(ExecuteResult.FromError(parseResult));
@@ -117,12 +117,11 @@ namespace Discord.Commands
                 paramList[i] = parseResult.ParamValues[i].Values.First().Value;
             }
 
-            return ExecuteAsync(context, argList, paramList, map);
+            return ExecuteAsync(context, argList, paramList, services);
         }
-        public async Task<ExecuteResult> ExecuteAsync(ICommandContext context, IEnumerable<object> argList, IEnumerable<object> paramList, IDependencyMap map)
+        public async Task<ExecuteResult> ExecuteAsync(ICommandContext context, IEnumerable<object> argList, IEnumerable<object> paramList, IServiceProvider services)
         {
-            if (map == null)
-                map = DependencyMap.Empty;
+            services = services ?? EmptyServiceProvider.Instance;
 
             try
             {
@@ -132,7 +131,7 @@ namespace Discord.Commands
                 {
                     var parameter = Parameters[position];
                     var argument = args[position];
-                    var result = await parameter.CheckPreconditionsAsync(context, argument, map).ConfigureAwait(false);
+                    var result = await parameter.CheckPreconditionsAsync(context, argument, services).ConfigureAwait(false);
                     if (!result.IsSuccess)
                         return ExecuteResult.FromError(result);
                 }
@@ -140,12 +139,12 @@ namespace Discord.Commands
                 switch (RunMode)
                 {
                     case RunMode.Sync: //Always sync
-                        await ExecuteAsyncInternal(context, args, map).ConfigureAwait(false);
+                        await ExecuteAsyncInternal(context, args, services).ConfigureAwait(false);
                         break;
                     case RunMode.Async: //Always async
                         var t2 = Task.Run(async () => 
                         {
-                            await ExecuteAsyncInternal(context, args, map).ConfigureAwait(false);
+                            await ExecuteAsyncInternal(context, args, services).ConfigureAwait(false);
                         });
                         break;
                 }
@@ -157,12 +156,12 @@ namespace Discord.Commands
             }
         }
 
-        private async Task ExecuteAsyncInternal(ICommandContext context, object[] args, IDependencyMap map)
+        private async Task ExecuteAsyncInternal(ICommandContext context, object[] args, IServiceProvider services)
         {
             await Module.Service._cmdLogger.DebugAsync($"Executing {GetLogText(context)}").ConfigureAwait(false);
             try
             {
-                await _action(context, args, map).ConfigureAwait(false);
+                await _action(context, args, services).ConfigureAwait(false);
             }
             catch (Exception ex)
             {

src/Discord.Net.Commands/Info/ParameterInfo.cs

@@ -3,6 +3,7 @@ using System;
 using System.Collections.Generic;
 using System.Collections.Immutable;
 using System.Threading.Tasks;
+using Microsoft.Extensions.DependencyInjection;
 
 namespace Discord.Commands
 {
@@ -39,14 +40,13 @@ namespace Discord.Commands
             _reader = builder.TypeReader;
         }
 
-        public async Task<PreconditionResult> CheckPreconditionsAsync(ICommandContext context, object arg, IDependencyMap map = null)
+        public async Task<PreconditionResult> CheckPreconditionsAsync(ICommandContext context, object arg, IServiceProvider services = null)
         {
-            if (map == null)
-                map = DependencyMap.Empty;
+            services = EmptyServiceProvider.Instance;
 
             foreach (var precondition in Preconditions)
             {
-                var result = await precondition.CheckPermissions(context, this, arg, map).ConfigureAwait(false);
+                var result = await precondition.CheckPermissions(context, this, arg, services).ConfigureAwait(false);
                 if (!result.IsSuccess)
                     return result;
             }

src/Discord.Net.Commands/Utilities/ReflectionUtils.cs

@@ -2,88 +2,79 @@
 using System.Collections.Generic;
 using System.Linq;
 using System.Reflection;
+using Microsoft.Extensions.DependencyInjection;
 
 namespace Discord.Commands
 {
     internal static class ReflectionUtils
     {
-        private static readonly TypeInfo objectTypeInfo = typeof(object).GetTypeInfo();
+        private static readonly TypeInfo _objectTypeInfo = typeof(object).GetTypeInfo();
 
-        internal static T CreateObject<T>(TypeInfo typeInfo, CommandService service, IDependencyMap map = null)
-            => CreateBuilder<T>(typeInfo, service)(map);
+        internal static T CreateObject<T>(TypeInfo typeInfo, CommandService commands, IServiceProvider services = null)
+            => CreateBuilder<T>(typeInfo, commands)(services);
+        internal static Func<IServiceProvider, T> CreateBuilder<T>(TypeInfo typeInfo, CommandService commands)
+        {
+            var constructor = GetConstructor(typeInfo);
+            var parameters = constructor.GetParameters();
+            var properties = GetProperties(typeInfo);
+
+            return (services) =>
+            {
+                var args = new object[parameters.Length];
+                for (int i = 0; i < parameters.Length; i++)
+                    args[i] = GetMember(commands, services, parameters[i].ParameterType, typeInfo);
+                var obj = InvokeConstructor<T>(constructor, args, typeInfo);
 
-        private static System.Reflection.PropertyInfo[] GetProperties(TypeInfo typeInfo)
+                foreach(var property in properties)
+                    property.SetValue(obj, GetMember(commands, services, property.PropertyType, typeInfo));
+                return obj;
+            };
+        }
+        private static T InvokeConstructor<T>(ConstructorInfo constructor, object[] args, TypeInfo ownerType)
         {
-            var result = new List<System.Reflection.PropertyInfo>();
-            while (typeInfo != objectTypeInfo)
+            try
             {
-                foreach (var prop in typeInfo.DeclaredProperties)
-                {
-                    if (prop.SetMethod?.IsPublic == true && prop.GetCustomAttribute<DontInjectAttribute>() == null)
-                        result.Add(prop);
-                }
-                typeInfo = typeInfo.BaseType.GetTypeInfo();
+                return (T)constructor.Invoke(args);
+            }
+            catch (Exception ex)
+            {
+                throw new Exception($"Failed to create \"{ownerType.FullName}\"", ex);
             }
-            return result.ToArray();
         }
 
-        internal static Func<IDependencyMap, T> CreateBuilder<T>(TypeInfo typeInfo, CommandService service)
+        private static ConstructorInfo GetConstructor(TypeInfo ownerType)
         {
-            var constructors = typeInfo.DeclaredConstructors.Where(x => !x.IsStatic).ToArray();
+            var constructors = ownerType.DeclaredConstructors.Where(x => !x.IsStatic).ToArray();
             if (constructors.Length == 0)
-                throw new InvalidOperationException($"No constructor found for \"{typeInfo.FullName}\"");
+                throw new InvalidOperationException($"No constructor found for \"{ownerType.FullName}\"");
             else if (constructors.Length > 1)
-                throw new InvalidOperationException($"Multiple constructors found for \"{typeInfo.FullName}\"");
-
-            var constructor = constructors[0];
-            System.Reflection.ParameterInfo[] parameters = constructor.GetParameters();
-            System.Reflection.PropertyInfo[] properties = GetProperties(typeInfo)
-                  .Where(p => p.SetMethod?.IsPublic == true && p.GetCustomAttribute<DontInjectAttribute>() == null)
-                  .ToArray();
-
-            return (map) =>
+                throw new InvalidOperationException($"Multiple constructors found for \"{ownerType.FullName}\"");
+            return constructors[0];
+        }
+        private static System.Reflection.PropertyInfo[] GetProperties(TypeInfo ownerType)
+        {
+            var result = new List<System.Reflection.PropertyInfo>();
+            while (ownerType != _objectTypeInfo)
             {
-                object[] args = new object[parameters.Length];
-
-                for (int i = 0; i < parameters.Length; i++)
-                {
-                    var parameter = parameters[i];
-                    args[i] = GetMember(parameter.ParameterType, map, service, typeInfo);
-                }
-
-                T obj;
-                try
-                {
-                    obj = (T)constructor.Invoke(args);
-                }
-                catch (Exception ex)
-                {
-                    throw new Exception($"Failed to create \"{typeInfo.FullName}\"", ex);
-                }
-
-                foreach(var property in properties)
+                foreach (var prop in ownerType.DeclaredProperties)
                 {
-                    property.SetValue(obj, GetMember(property.PropertyType, map, service, typeInfo));
+                    if (prop.SetMethod?.IsPublic == true && prop.GetCustomAttribute<DontInjectAttribute>() == null)
+                        result.Add(prop);
                 }
-                return obj;
-            };
+                ownerType = ownerType.BaseType.GetTypeInfo();
+            }
+            return result.ToArray();
         }
-
-        private static readonly TypeInfo _dependencyTypeInfo = typeof(IDependencyMap).GetTypeInfo();
-
-        internal static object GetMember(Type targetType, IDependencyMap map, CommandService service, TypeInfo baseType)
+        private static object GetMember(CommandService commands, IServiceProvider services, Type memberType, TypeInfo ownerType)
         {
-            object arg;
-            if (map == null || !map.TryGet(targetType, out arg))
-            {
-                if (targetType == typeof(CommandService))
-                    arg = service;
-                else if (targetType == typeof(IDependencyMap) || targetType == map.GetType())
-                    arg = map;
-                else
-                    throw new InvalidOperationException($"Failed to create \"{baseType.FullName}\", dependency \"{targetType.Name}\" was not found.");
-            }
-            return arg;
+            if (memberType == typeof(CommandService))
+                return commands;
+            if (memberType == typeof(IServiceProvider) || memberType == services.GetType())
+                return services;
+            var service = services?.GetService(memberType);
+            if (service != null)
+                return service;
+            throw new InvalidOperationException($"Failed to create \"{ownerType.FullName}\", dependency \"{memberType.Name}\" was not found.");
         }
     }
 }