## v0.3.19

- 兼容 GetTableByEntity 有可能因为传入数组类型的错误；
- 修复 UnitOfWork 事务创建逻辑 bug；
- 增加 FreeSql.DbContext 扩展包；
- 调整 UnitOfWork、DbContext 不提交时默认会回滚；

FreeSql.DbContext/DbContext.cs

@@ -0,0 +1,94 @@
+using SafeObjectPool;
+using System;
+using System.Collections.Generic;
+using System.Collections.Concurrent;
+using System.Data.Common;
+using System.Linq;
+using System.Reflection;
+
+namespace FreeSql {
+	public abstract class DbContext : IDisposable {
+
+		internal IFreeSql _orm;
+		internal IFreeSql _fsql => _orm ?? throw new ArgumentNullException("请在 OnConfiguring 或 AddFreeDbContext 中配置 UseFreeSql");
+
+		Object<DbConnection> _conn;
+		DbTransaction _tran;
+
+		static ConcurrentDictionary<Type, PropertyInfo[]> _dicGetDbSetProps = new ConcurrentDictionary<Type, PropertyInfo[]>();
+		protected DbContext() {
+
+			var builder = new DbContextOptionsBuilder();
+			OnConfiguring(builder);
+			_orm = builder._fsql;
+
+			var props = _dicGetDbSetProps.GetOrAdd(this.GetType(), tp => 
+				tp.GetProperties(BindingFlags.NonPublic | BindingFlags.Instance | BindingFlags.Public)
+					.Where(a => a.PropertyType.IsGenericType &&
+						a.PropertyType == typeof(DbSet<>).MakeGenericType(a.PropertyType.GenericTypeArguments[0])).ToArray());
+
+			foreach (var prop in props) {
+				var set = this.Set(prop.PropertyType.GenericTypeArguments[0]);
+
+				prop.SetValue(this, set);
+				AllSets.Add(prop, set);
+			}
+		}
+
+		protected virtual void OnConfiguring(DbContextOptionsBuilder builder) {
+			
+		}
+
+		public DbSet<TEntity> Set<TEntity>() where TEntity : class => this.Set(typeof(TEntity)) as DbSet<TEntity>;
+		public object Set(Type entityType) => Activator.CreateInstance(typeof(BaseDbSet<>).MakeGenericType(entityType), this);
+
+		protected Dictionary<PropertyInfo, object> AllSets => new Dictionary<PropertyInfo, object>();
+
+		public void SaveChanges() {
+			Commit();
+		}
+
+		void ReturnObject() {
+			_fsql.Ado.MasterPool.Return(_conn);
+			_tran = null;
+			_conn = null;
+		}
+		internal DbTransaction GetOrBeginTransaction(bool isCreate = true) {
+
+			if (_tran != null) return _tran;
+			if (isCreate == false) return null;
+			if (_conn != null) _fsql.Ado.MasterPool.Return(_conn);
+
+			_conn = _fsql.Ado.MasterPool.Get();
+			try {
+				_tran = _conn.Value.BeginTransaction();
+			} catch {
+				ReturnObject();
+				throw;
+			}
+			return _tran;
+		}
+
+		void Commit() {
+			if (_tran != null) {
+				try {
+					_tran.Commit();
+				} finally {
+					ReturnObject();
+				}
+			}
+		}
+		void Rollback() {
+			if (_tran != null) {
+				try {
+					_tran.Rollback();
+				} finally {
+					ReturnObject();
+				}
+			}
+		}
+		public void Dispose() {
+			this.Rollback();
+		}
+	}
+}