Linq表达式-设置嵌套的属性值

本文关键字：属性 嵌套 设置 表达式 Linq | 更新日期: 2023-09-27 18:07:47

我一直在使用以下方法将某些属性设置为null，效果很好:

    public static void Detach<TObject>(TObject parentObj, params Expression<Func<TObject, object>>[] detachEntities)
    {
        foreach (var detachEntity in detachEntities)
        {
            var prop = (PropertyInfo)((MemberExpression)detachEntity.Body).Member;
            prop.SetValue(parentObj, null);
        }
    }

调用该方法，我使用:Detach(personObj, x => x.Car) -非常简单

但是我正在尝试做以下事情:

Detach(personObj, x => x.Car.Make);

或者

Detach(personObj, x => x.Dogs.Select(s => s.Breed), x => x.Car.Make);

因此，我试图获得表达式中的每个属性并将其值设置为null。

任何帮助都将是感激的。谢谢!

Linq表达式-设置嵌套的属性值

好的，所以这可能不是完美的，但它的工作-我是开放的任何改进:

public static void Detach<TObject>(TObject parentObj, params Expression<Func<TObject, object>>[] detachEntities)
        {
            foreach (var detachEntity in detachEntities)
            {
                var methodCallExpression = detachEntity.Body as MethodCallExpression;
                var member = methodCallExpression?.Arguments[0] as MemberExpression;
                PropertyInfo prop;
                if (member != null)
                {
                    prop = (PropertyInfo)member.Member;
                    prop.SetValue(parentObj, null);
                }
                var memberExpression = detachEntity.Body as MemberExpression;
                var expression = memberExpression?.Expression as MemberExpression;                
                switch (memberExpression?.Expression.NodeType)
                {
                    case ExpressionType.Parameter:
                        prop = (PropertyInfo)memberExpression.Member;
                        prop.SetValue(parentObj, null);
                        break;
                    case ExpressionType.MemberAccess:
                        if (expression != null)
                        {
                            prop = (PropertyInfo)expression.Member;
                            prop.SetValue(parentObj, null);
                        }
                        break;
                }               
            }
        }
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