Some adjustment to the Crypto clients

CryptoExchange.Net/Clients/CryptoBaseClient.cs

@@ -1,10 +1,6 @@
-using CryptoExchange.Net.Interfaces;
-using CryptoExchange.Net.Interfaces.CommonClients;
-using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.DependencyInjection;
 using System;
 using System.Collections.Generic;
-using System.Linq;
-using System.Text;
 
 namespace CryptoExchange.Net.Clients
 {
@@ -42,6 +38,10 @@ namespace CryptoExchange.Net.Clients
         /// <returns></returns>
         public T TryGet<T>(Func<T> createFunc)
         {
+            var type = typeof(T);
+            if (_serviceCache.TryGetValue(type, out var value))
+                return (T)value;
+
             if (_serviceProvider == null)
             {
                 // Create with default options
@@ -50,16 +50,8 @@ namespace CryptoExchange.Net.Clients
                 return createResult;
             }
 
-            var type = typeof(T);
-            if (_serviceCache.TryGetValue(type, out var value))
-                return (T)value;
-
-            var result = _serviceProvider.GetRequiredService<T>();
-            if (result == null)
-            {
-                // Does this mean the AddXX() hasn't been done?
-            }
-
+            var result = _serviceProvider.GetService<T>() 
+                ?? throw new InvalidOperationException($"No service was found for {typeof(T).Name}, make sure the exchange is registered in dependency injection with the `services.Add[Exchange]()` method");
             _serviceCache.Add(type, result!);
             return result;
         }

CryptoExchange.Net/Clients/CryptoRestClient.cs

@@ -4,13 +4,19 @@ using Microsoft.Extensions.DependencyInjection;
 using System;
 using System.Collections.Generic;
 using System.Linq;
-using System.Text;
 
 namespace CryptoExchange.Net.Clients
 {
     /// <inheritdoc />
     public class CryptoRestClient : CryptoBaseClient, ICryptoRestClient
     {
+        /// <summary>
+        /// ctor
+        /// </summary>
+        public CryptoRestClient()
+        {
+        }
+
         /// <summary>
         /// ctor
         /// </summary>
@@ -20,7 +26,7 @@ namespace CryptoExchange.Net.Clients
         }
 
         /// <summary>
-        /// Try get a client by type for the service collection
+        /// Get a list of the registered ISpotClient implementations
         /// </summary>
         /// <returns></returns>
         public IEnumerable<ISpotClient> GetSpotClients()
@@ -30,5 +36,12 @@ namespace CryptoExchange.Net.Clients
 
             return _serviceProvider.GetServices<ISpotClient>().ToList();
         }
+
+        /// <summary>
+        /// Get an ISpotClient implementation by exchange name
+        /// </summary>
+        /// <param name="exchangeName"></param>
+        /// <returns></returns>
+        public ISpotClient? SpotClient(string exchangeName) => _serviceProvider.GetServices<ISpotClient>()?.SingleOrDefault(s => s.ExchangeName.Equals(exchangeName, StringComparison.InvariantCultureIgnoreCase));
     }
 }

CryptoExchange.Net/Clients/CryptoSocketClient.cs

@@ -1,16 +1,18 @@
 using CryptoExchange.Net.Interfaces;
-using CryptoExchange.Net.Interfaces.CommonClients;
-using Microsoft.Extensions.DependencyInjection;
 using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Text;
 
 namespace CryptoExchange.Net.Clients
 {
     /// <inheritdoc />
     public class CryptoSocketClient : CryptoBaseClient, ICryptoSocketClient
     {
+        /// <summary>
+        /// ctor
+        /// </summary>
+        public CryptoSocketClient()
+        {
+        }
+
         /// <summary>
         /// ctor
         /// </summary>

CryptoExchange.Net/Interfaces/ICryptoRestClient.cs

@@ -16,6 +16,14 @@ namespace CryptoExchange.Net.Interfaces
         /// </summary>
         /// <returns></returns>
         IEnumerable<ISpotClient> GetSpotClients();
+
+        /// <summary>
+        /// Get an ISpotClient implementation by exchange name
+        /// </summary>
+        /// <param name="exchangeName"></param>
+        /// <returns></returns>
+        ISpotClient? SpotClient(string exchangeName);
+
         /// <summary>
         /// Try get 
         /// </summary>