一直都在想着用ADO.NET Entity Framework开发项目，只是Entity Framework 中不能同时更新多条记录。所以一直没有使作其开发。最近在看到了一些LINQ TO SQL的一些扩展方法，本人就LINQ TO SQL的扩展也实行了对Entity Framework扩展。主要代码如下：
以下是更新的扩展代码：
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 | /// <summary>/// 更新满足条件的实体，返回更新实体的条数 /// </summary>/// <typeparam name="T">更新的类型</typeparam>/// <param name="Entity">实体类</param>/// <param name="Predicate">更新的条件</param>/// <param name="Updater">更新的值</param>/// <returns>int</returns>public static int UpdateEntity<T>(this ObjectSet<T> Entity, Expression<Func<T, bool>> Predicate, Expression<Func<T, T>> Updater) where T : class{ ConditionBuilder Builder = new ConditionBuilder(); Builder.Build(Predicate.Body); string sqlCondition = Builder.Condition; //获取Update的赋值语句 var updateMemberExpr = (MemberInitExpression)Updater.Body; var updateMemberCollection = updateMemberExpr.Bindings.Cast<MemberAssignment>().Select(c => new { Name = c.Member.Name, Value = ((ConstantExpression)c.Expression).Value }); int i = Builder.Arguments.Length; string sqlUpdateBlock = string.Join(", ", updateMemberCollection.Select(c => string.Format("[{0}]={1}", c.Name, "{" + (i++) + "}")).ToArray()); string commandText = string.Format("Update {0} Set {1} Where {2}", Entity.EntitySet.Name, sqlUpdateBlock, sqlCondition); //获取SQL参数数组 (包括查询参数和赋值参数) var args = Builder.Arguments.Union(updateMemberCollection.Select(c => c.Value)).ToArray(); var Result = Entity.Context.ExecuteStoreCommand(commandText, args); return Result;} |
以下是删除方法的扩展：
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 | /// <summary> /// 删除满足条件的实体，返回删除实体的条数 /// </summary>/// <typeparam name="T">删除的类型</typeparam>/// <param name="Entity">实体类</param>/// <param name="Predicate">删除的条件</param>/// <returns>int</returns>public static int DeleteEntity<T>(this ObjectSet<T> Entity, Expression<Func<T, bool>> Predicate) where T : class{ //查询条件表达式转换成SQL的条件语句 ConditionBuilder Builder = new ConditionBuilder(); Builder.Build(Predicate.Body); string sqlCondition = Builder.Condition; //获取SQL参数数组 var args = Builder.Arguments; var Result = Entity.Context.ExecuteStoreCommand("Delete From " + Entity.EntitySet.Name + " Where " + sqlCondition, args); return Result;} |
批量更新/批量删除主要是通过拼接SQL语句执行。还需高手多多指点。点击此处下载源码
