Fixed #1417 EF Unit of work: Collection was modified; enumeration operation may not execute problem.

framework/src/Volo.Abp.Uow/Volo/Abp/Uow/UnitOfWork.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using System.Collections.Immutable;
 using System.Threading;
 using System.Threading.Tasks;
 using Microsoft.Extensions.Options;
@@ -76,7 +77,7 @@ namespace Volo.Abp.Uow
 
         public virtual void SaveChanges()
         {
-            foreach (var databaseApi in _databaseApis.Values)
+            foreach (var databaseApi in GetAllActiveDatabaseApis())
             {
                 (databaseApi as ISupportsSavingChanges)?.SaveChanges();
             }
@@ -84,7 +85,7 @@ namespace Volo.Abp.Uow
 
         public virtual async Task SaveChangesAsync(CancellationToken cancellationToken = default)
         {
-            foreach (var databaseApi in _databaseApis.Values)
+            foreach (var databaseApi in GetAllActiveDatabaseApis())
             {
                 if (databaseApi is ISupportsSavingChanges)
                 {
@@ -93,6 +94,16 @@ namespace Volo.Abp.Uow
             }
         }
 
+        public IReadOnlyList<IDatabaseApi> GetAllActiveDatabaseApis()
+        {
+            return _databaseApis.Values.ToImmutableList();
+        }
+
+        public IReadOnlyList<ITransactionApi> GetAllActiveTransactionApis()
+        {
+            return _transactionApis.Values.ToImmutableList();
+        }
+
         public virtual void Complete()
         {
             if (_isRolledback)
@@ -276,7 +287,7 @@ namespace Volo.Abp.Uow
 
         private void DisposeTransactions()
         {
-            foreach (var transactionApi in _transactionApis.Values)
+            foreach (var transactionApi in GetAllActiveTransactionApis())
             {
                 try
                 {
@@ -298,7 +309,7 @@ namespace Volo.Abp.Uow
 
         protected virtual void RollbackAll()
         {
-            foreach (var databaseApi in _databaseApis.Values)
+            foreach (var databaseApi in GetAllActiveDatabaseApis())
             {
                 try
                 {
@@ -307,7 +318,7 @@ namespace Volo.Abp.Uow
                 catch { }
             }
 
-            foreach (var transactionApi in _transactionApis.Values)
+            foreach (var transactionApi in GetAllActiveTransactionApis())
             {
                 try
                 {
@@ -319,7 +330,7 @@ namespace Volo.Abp.Uow
 
         protected virtual async Task RollbackAllAsync(CancellationToken cancellationToken)
         {
-            foreach (var databaseApi in _databaseApis.Values)
+            foreach (var databaseApi in GetAllActiveDatabaseApis())
             {
                 if (databaseApi is ISupportsRollback)
                 {
@@ -331,7 +342,7 @@ namespace Volo.Abp.Uow
                 }
             }
 
-            foreach (var transactionApi in _transactionApis.Values)
+            foreach (var transactionApi in GetAllActiveTransactionApis())
             {
                 if (transactionApi is ISupportsRollback)
                 {
@@ -346,7 +357,7 @@ namespace Volo.Abp.Uow
 
         protected virtual void CommitTransactions()
         {
-            foreach (var transaction in _transactionApis.Values)
+            foreach (var transaction in GetAllActiveTransactionApis())
             {
                 transaction.Commit();
             }
@@ -354,7 +365,7 @@ namespace Volo.Abp.Uow
 
         protected virtual async Task CommitTransactionsAsync()
         {
-            foreach (var transaction in _transactionApis.Values)
+            foreach (var transaction in GetAllActiveTransactionApis())
             {
                 await transaction.CommitAsync();
             }