C# 使用 PropertyInfo.GetValue()

Using PropertyInfo.GetValue()

提问by Mass Dot Net

I have a class that creates a static array of all properties, using a static constructor. I also have a function -- GetNamesAndTypes() -- that lists the name & type of each property in that array.

我有一个类，它使用静态构造函数创建所有属性的静态数组。我还有一个函数——GetNamesAndTypes()——它列出了该数组中每个属性的名称和类型。

Now I want to create another instance-level function -- GetNamesAndTypesAndValues() -- that displays the name & type of each property in the class, as well as that instance's value. How would I do that? Here's the code that I've written so far:

现在我想创建另一个实例级函数——GetNamesAndTypesAndValues()——它显示类中每个属性的名称和类型，以及该实例的值。我该怎么做？这是我到目前为止编写的代码：

//StaticTest.cs
using System;
using System.ComponentModel;
using System.Globalization;
using System.Reflection;

namespace StaticTest
{
    public class ClassTest
    {
        private string m_A, m_B, m_C;
        private static PropertyInfo[] allClassProperties;

        static ClassTest()
        {
            Type type = typeof(ClassTest);
            allClassProperties = type.GetProperties();

            // Sort properties alphabetically by name 
            // (http://www.csharp-examples.net/reflection-property-names/)
            Array.Sort(allClassProperties, delegate(PropertyInfo p1, PropertyInfo p2)
            {
                return p1.Name.CompareTo(p2.Name);
            });
        }

        public int A
        {
            get { return Convert.ToInt32(m_A); }
            set { m_A = value.ToString(); }
        }

        public string B
        {
            get { return m_B; }
            set { m_B = value; }
        }

        public DateTime C
        {
            get { return DateTime.ParseExact("yyyyMMdd", m_C, 
                                  CultureInfo.InvariantCulture); }
            set { m_C = String.Format("{0:yyyyMMdd}", value); }
        }

        public static void GetNamesAndTypes()
        {
            foreach (PropertyInfo propertyInfo in allClassProperties)
            {
                Console.WriteLine("{0} [type = {1}]", propertyInfo.Name, 
                                           propertyInfo.PropertyType);
            }
        }

        public void GetNamesAndTypesAndValues()
        {
            foreach (PropertyInfo propertyInfo in allClassProperties)
            {
                Console.WriteLine("{0} [type = {1}]", propertyInfo.Name, 
                                             propertyInfo.PropertyType);
            }
        }
    }
}

//Program.cs
using System;
using System.Collections.Generic;
using StaticTest;

namespace ConsoleApplication2
{
    class Program
    {
        static void Main(string[] args)
        {
            Console.WriteLine("[static] GetNamesAndTypes()");
            ClassTest.GetNamesAndTypes();
            Console.WriteLine("");

            ClassTest classTest = new ClassTest();
            classTest.A = 4;
            classTest.B = @"bacon";
            classTest.C = DateTime.Now;
            Console.WriteLine("[instance] GetNamesAndTypesAndValues()");
            classTest.GetNamesAndTypesAndValues();

            Console.ReadLine();
        }
    }
}

I tried using propertyInfo.GetValue(), but I couldn't get it to work.

我尝试使用 propertyInfo.GetValue()，但我无法让它工作。

采纳答案by Yannick Motton

In your example propertyInfo.GetValue(this, null)should work. Consider altering GetNamesAndTypesAndValues()as follows:

在你的例子中propertyInfo.GetValue(this, null)应该有效。考虑更改GetNamesAndTypesAndValues()如下：

public void GetNamesAndTypesAndValues()
{
  foreach (PropertyInfo propertyInfo in allClassProperties)
  {
    Console.WriteLine("{0} [type = {1}] [value = {2}]",
      propertyInfo.Name,
      propertyInfo.PropertyType,
      propertyInfo.GetValue(this, null));
  }
}