check the requirement when CAP start.

src/DotNetCore.CAP.Kafka/CAP.KafkaCapOptionsExtension.cs

@@ -16,6 +16,8 @@ namespace DotNetCore.CAP
 
         public void AddServices(IServiceCollection services)
         {
+            services.AddSingleton<CapMessageQueueMakerService>();
+
             var kafkaOptions = new KafkaOptions();
             _configure?.Invoke(kafkaOptions);
             services.AddSingleton(kafkaOptions);

src/DotNetCore.CAP.MySql/CAP.MySqlCapOptionsExtension.cs

@@ -18,6 +18,7 @@ namespace DotNetCore.CAP
 
         public void AddServices(IServiceCollection services)
         {
+            services.AddSingleton<CapDatabaseStorageMarkerService>();
             services.AddSingleton<IStorage, MySqlStorage>();
             services.AddScoped<IStorageConnection, MySqlStorageConnection>();
             services.AddScoped<ICapPublisher, CapPublisher>();

src/DotNetCore.CAP.PostgreSql/CAP.PostgreSqlCapOptionsExtension.cs

@@ -18,6 +18,7 @@ namespace DotNetCore.CAP
 
         public void AddServices(IServiceCollection services)
         {
+            services.AddSingleton<CapDatabaseStorageMarkerService>();
             services.AddSingleton<IStorage, PostgreSqlStorage>();
             services.AddScoped<IStorageConnection, PostgreSqlStorageConnection>();
             services.AddScoped<ICapPublisher, CapPublisher>();

src/DotNetCore.CAP.RabbitMQ/CAP.RabbitMQCapOptionsExtension.cs

@@ -16,6 +16,8 @@ namespace DotNetCore.CAP
 
         public void AddServices(IServiceCollection services)
         {
+            services.AddSingleton<CapMessageQueueMakerService>();
+
             var options = new RabbitMQOptions();
             _configure?.Invoke(options);
             services.AddSingleton(options);

src/DotNetCore.CAP.SqlServer/CAP.SqlServerCapOptionsExtension.cs

@@ -18,6 +18,7 @@ namespace DotNetCore.CAP
 
         public void AddServices(IServiceCollection services)
         {
+            services.AddSingleton<CapDatabaseStorageMarkerService>();
             services.AddSingleton<IStorage, SqlServerStorage>();
             services.AddSingleton<IStorageConnection, SqlServerStorageConnection>();
             services.AddTransient<ICapPublisher, CapPublisher>();

src/DotNetCore.CAP/CAP.AppBuilderExtensions.cs

 using System;
 using DotNetCore.CAP;
 using DotNetCore.CAP.Dashboard.GatewayProxy;
-using Microsoft.AspNetCore.Http;
 using Microsoft.Extensions.DependencyInjection;
 
 namespace Microsoft.AspNetCore.Builder
@@ -23,12 +22,7 @@ namespace Microsoft.AspNetCore.Builder
                 throw new ArgumentNullException(nameof(app));
             }
 
-            var marker = app.ApplicationServices.GetService<CapMarkerService>();
-
-            if (marker == null)
-            {
-                throw new InvalidOperationException("Add Cap must be called on the service collection.");
-            }
+            CheckRequirement(app);
 
             var provider = app.ApplicationServices;
             var bootstrapper = provider.GetRequiredService<IBootstrapper>();
@@ -36,21 +30,42 @@ namespace Microsoft.AspNetCore.Builder
             return app;
         }
 
+        ///<summary>
+        /// Enables cap dashboard for the current application
+        /// </summary>
+        /// <param name="app">The <see cref="IApplicationBuilder"/> instance this method extends.</param>
+        /// <returns>The <see cref="IApplicationBuilder"/> instance this method extends.</returns>
         public static IApplicationBuilder UseCapDashboard(this IApplicationBuilder app)
         {
-            if (app == null) throw new ArgumentNullException(nameof(app));          
+            if (app == null) throw new ArgumentNullException(nameof(app));
 
-            var marker = app.ApplicationServices.GetService<CapMarkerService>();
+            CheckRequirement(app);
+
+            app.UseMiddleware<GatewayProxyMiddleware>();
+            app.UseMiddleware<DashboardMiddleware>();
 
+            return app;
+        }
+
+        private static void CheckRequirement(IApplicationBuilder app)
+        {
+            var marker = app.ApplicationServices.GetService<CapMarkerService>();
             if (marker == null)
             {
-                throw new InvalidOperationException("Add Cap must be called on the service collection.");
+                throw new InvalidOperationException("AddCap must be called on the service collection.   eg: services.AddCap(...)");
             }
 
-            app.UseMiddleware<GatewayProxyMiddleware>();
-            app.UseMiddleware<DashboardMiddleware>();
-           
-            return app;
+            var messageQueuemarker = app.ApplicationServices.GetService<CapMessageQueueMakerService>();
+            if (messageQueuemarker == null)
+            {
+                throw new InvalidOperationException("You must be config used database provider at AddCap() options!   eg: services.AddCap(options=>{ options.UseKafka(...) })");
+            }
+
+            var databaseMarker = app.ApplicationServices.GetService<CapDatabaseStorageMarkerService>();
+            if (databaseMarker == null)
+            {
+                throw new InvalidOperationException("You must be config used database provider at AddCap() options!   eg: services.AddCap(options=>{ options.UseSqlServer(...) })");
+            }
         }
     }
 }
\ No newline at end of file

src/DotNetCore.CAP/CAP.Builder.cs

@@ -10,6 +10,22 @@ namespace DotNetCore.CAP
     {
     }
 
+    /// <summary>
+    /// Used to verify cap database storage extension was added on a ServiceCollection
+    /// </summary>
+    public class CapDatabaseStorageMarkerService
+    {
+
+    }
+
+    /// <summary>
+    /// Used to verify cap message queue extension was added on a ServiceCollection
+    /// </summary>
+    public class CapMessageQueueMakerService
+    {
+
+    }
+
     /// <summary>
     /// Allows fine grained configuration of CAP services.
     /// </summary>