Improved

framework/src/Volo.Abp.MongoDB/Volo.Abp.MongoDB.csproj

@@ -15,7 +15,7 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="MongoDB.Driver" Version="2.11.0" />
+    <PackageReference Include="MongoDB.Driver" Version="2.11.1" />
   </ItemGroup>
 
   <ItemGroup>

framework/src/Volo.Abp.MongoDB/Volo/Abp/MongoDB/AbpMongoDbContext.cs

@@ -29,6 +29,12 @@ namespace Volo.Abp.MongoDB
             return Database.GetCollection<T>(GetCollectionName<T>());
         }
 
+        public virtual void InitializeCollections(IMongoDatabase database)
+        {
+            Database = database;
+            ModelSource.GetModel(this);
+        }
+
         protected virtual string GetCollectionName<T>()
         {
             return GetEntityModel<T>().CollectionName;

framework/src/Volo.Abp.MongoDB/Volo/Abp/MongoDB/AbpMongoDbModule.cs

@@ -1,7 +1,12 @@
-using Microsoft.Extensions.DependencyInjection.Extensions;
+using System;
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.DependencyInjection.Extensions;
+using MongoDB.Driver;
+using Volo.Abp.Data;
 using Volo.Abp.Domain;
 using Volo.Abp.Domain.Repositories.MongoDB;
 using Volo.Abp.Modularity;
+using Volo.Abp.MongoDB.DependencyInjection;
 using Volo.Abp.Uow.MongoDB;
 
 namespace Volo.Abp.MongoDB
@@ -9,6 +14,11 @@ namespace Volo.Abp.MongoDB
     [DependsOn(typeof(AbpDddDomainModule))]
     public class AbpMongoDbModule : AbpModule
     {
+        public override void PreConfigureServices(ServiceConfigurationContext context)
+        {
+            context.Services.AddConventionalRegistrar(new AbpMongoDbConventionalRegistrar());
+        }
+
         public override void ConfigureServices(ServiceConfigurationContext context)
         {
             context.Services.TryAddTransient(
@@ -26,5 +36,31 @@ namespace Volo.Abp.MongoDB
                 typeof(MongoDbRepositoryFilterer<,>)
             );
         }
+
+        public override void OnApplicationInitialization(ApplicationInitializationContext context)
+        {
+            InitializeAllCollections(context.ServiceProvider);
+        }
+
+        private void InitializeAllCollections(IServiceProvider serviceProvider)
+        {
+            var dbContexts = serviceProvider.GetServices<IAbpMongoDbContext>();
+            var connectionStringResolver = serviceProvider.GetService<IConnectionStringResolver>();
+
+            foreach (var dbContext in dbContexts)
+            {
+                var connectionString = connectionStringResolver.Resolve(ConnectionStringNameAttribute.GetConnStringName(dbContext.GetType()));
+                var mongoUrl = new MongoUrl(connectionString);
+                var databaseName = mongoUrl.DatabaseName;
+                var client = new MongoClient(mongoUrl);
+
+                if (databaseName.IsNullOrWhiteSpace())
+                {
+                    databaseName = ConnectionStringNameAttribute.GetConnStringName(dbContext.GetType());
+                }
+
+                (dbContext as AbpMongoDbContext)?.InitializeCollections(client.GetDatabase(databaseName));
+            }
+        }
     }
 }

framework/src/Volo.Abp.MongoDB/Volo/Abp/MongoDB/DependencyInjection/AbpMongoDbConventionalRegistrar.cs

@@ -0,0 +1,27 @@
+using System;
+using Microsoft.Extensions.DependencyInjection;
+using Volo.Abp.DependencyInjection;
+
+namespace Volo.Abp.MongoDB.DependencyInjection
+{
+    public class AbpMongoDbConventionalRegistrar : DefaultConventionalRegistrar
+    {
+        public override void AddType(IServiceCollection services, Type type)
+        {
+            if (!typeof(IAbpMongoDbContext).IsAssignableFrom(type) || type == typeof(AbpMongoDbContext))
+            {
+                return;
+            }
+
+            var dependencyAttribute = GetDependencyAttributeOrNull(type);
+            var lifeTime = GetLifeTimeOrNull(type, dependencyAttribute);
+
+            if (lifeTime == null)
+            {
+                return;
+            }
+
+            services.Add(ServiceDescriptor.Describe(typeof(IAbpMongoDbContext), type, ServiceLifetime.Transient));
+        }
+    }
+}

framework/src/Volo.Abp.MongoDB/Volo/Abp/Uow/MongoDB/UnitOfWorkMongoDbContextProvider.cs

@@ -43,7 +43,7 @@ namespace Volo.Abp.Uow.MongoDB
             //TODO: Create only single MongoDbClient per connection string in an application (extract MongoClientCache for example).
             var databaseApi = unitOfWork.GetOrAddDatabaseApi(
                 dbContextKey,
-                () => new MongoDbDatabaseApi<TMongoDbContext>(CreateDbContext(unitOfWork,mongoUrl,databaseName)));
+                () => new MongoDbDatabaseApi<TMongoDbContext>(CreateDbContext(unitOfWork, mongoUrl, databaseName)));
 
             return ((MongoDbDatabaseApi<TMongoDbContext>) databaseApi).DbContext;
         }
@@ -52,9 +52,29 @@ namespace Volo.Abp.Uow.MongoDB
         {
             var client = new MongoClient(mongoUrl);
             var database = client.GetDatabase(databaseName);
-            var dbContext = unitOfWork.ServiceProvider.GetRequiredService<TMongoDbContext>();
 
             if (unitOfWork.Options.IsTransactional)
+            {
+                return CreateDbContextWithTransaction(unitOfWork, mongoUrl, client, database);
+            }
+
+            var dbContext = unitOfWork.ServiceProvider.GetRequiredService<TMongoDbContext>();
+            dbContext.ToAbpMongoDbContext().InitializeDatabase(database, null);
+
+            return dbContext;
+        }
+
+        public TMongoDbContext CreateDbContextWithTransaction(
+            IUnitOfWork unitOfWork,
+            MongoUrl url,
+            MongoClient client,
+            IMongoDatabase database)
+        {
+            var transactionApiKey = $"MongoDb_{url}";
+            var activeTransaction = unitOfWork.FindTransactionApi(transactionApiKey) as MongoDbTransactionApi;
+            var dbContext = unitOfWork.ServiceProvider.GetRequiredService<TMongoDbContext>();
+
+            if (activeTransaction?.SessionHandle == null)
             {
                 var session = client.StartSession();
 
@@ -65,7 +85,6 @@ namespace Volo.Abp.Uow.MongoDB
 
                 session.StartTransaction();
 
-                var transactionApiKey = $"MongoDb_{mongoUrl}";
                 unitOfWork.AddTransactionApi(
                     transactionApiKey,
                     new MongoDbTransactionApi(session)
@@ -75,7 +94,7 @@ namespace Volo.Abp.Uow.MongoDB
             }
             else
             {
-                dbContext.ToAbpMongoDbContext().InitializeDatabase(database, null);
+                dbContext.ToAbpMongoDbContext().InitializeDatabase(database, activeTransaction.SessionHandle);
             }
 
             return dbContext;