[ASP.NET2.0MVPHacksandTips]TuningObjectsforDebugging

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原作者: [db:作者] 来自: [db:来源] 收藏邀请

使用 DebuggerBrowsable 特性可以设置调式运行时属性在Watch窗口中的可视状态。
DebuggerBrowsable 使用 DebuggerBrowsableState 枚举来初始化，它有三个值：

Collapsed 默认行为，显示元素
Never 不在Debug窗口中显示元素
RootHidden 隐藏父元素，直接显示子元素

Person
    {
        private string _lastName = string.Empty;
        private string _firstName = string.Empty;
        private int _age = 0;
        private List<Person> _children = new List<Person>();
        private List<string> _pets = new List<string>();
        private List<string> _cars = new List<string>();

        public string LastName
        {
            get { return _lastName; }
            set { _lastName = value; }
        }

        public string FirstName
        {
            get { return _firstName; }
            set { _firstName = value; }
        }

        public int Age
        {
            get { return _age; }
            set { _age = value; }
        }

        [DebuggerBrowsable(DebuggerBrowsableState.Collapsed)]
        public List<Person> Children
        {
            get{return _children;}
        }

        [DebuggerBrowsable(DebuggerBrowsableState.Never)]
        public List<string> Pets
        {
            get { return _pets; }
        }

        [DebuggerBrowsable(DebuggerBrowsableState.RootHidden)]
        public List<string> Cars
        {
            get { return _cars; }
        }

        public Person()
        {
        }

        public Person(string lastName, string firstName, int age)
        {
            _lastName = lastName;
            _firstName = firstName;
            _age = age;
        }
    }

通过Type Proxy简化对象查看

使用 [DebuggerTypeProxy(typeof(XXXProxy))] 特性标记要简化查看的类，XXXProxy 是新创建的类，目的只是为了定义要在Watch窗口显示的属性

PersonProxy
    {
        private Person _person;

        public PersonProxy(Person person)
        {
            _person = person;
        }

        public string Children
        {
            get
            {
                string[] children = new string[_person.Children.Count];

                for(int i = 0; i<_person.Children.Count;i++)
                {
                   children[i] = _person.Children[i].FirstName;
                }

                return string.Join(", ",children);
            }
        }

        public string Pets
        {
            get { return string.Join(", ", _person.Pets.ToArray()); }
        }

        public string Cars
        {
            get { return string.Join(", ", _person.Cars.ToArray()); }
        }

        public string Person
        {
            get
            {
                return "Name = " + _person.FirstName + " " + _person.LastName +
                   ", Age = " + _person.Age;
            }
        }
    }

显示直观的Watch值

,
     Type = "Alcohol Age Check")]
    public string AlcoholAgeCheck
    {
     get { return string.Empty; }
    }

如上代码，可以通过 DebuggerDisplay 特性使用条件判断来自定义Watch窗口显示的信息
如果单个三元运算不能满足，可以将判断代码封装到一个方法中去，如：

ValidateObject()
    {
        List<string> violations = new List<string>();

        //make sure that a first name has been specified
        if (0 == _person.FirstName.Length)
        {
            violations.Add("FirstName is empty");
        }

        //make sure that a last name has been specified
        if (0 == _person.LastName.Length)
        {
            violations.Add("LastName is empty");
        }

        //make sure that age is greater than 0
        if (0 > _person.Age)
        {
            violations.Add("Age is less than 0");
        }

        //put additional validations here

        //return results to DebuggerDisplay attribute
        return string.Join(", ", violations.ToArray());
    }

    [DebuggerDisplay("{ValidateObject()}")]
    public string BusinessRulesViolations
    {
        get { return string.Empty; }
    }