ADO.NET Entity Framework 批量更新/批量删除扩展

2011-07-30 11:57 ※森林小居※ 阅读(6879) 评论(33) 编辑收藏举报

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：

/// <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：

/// <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;
}