使用反射从字段中获取属性

Question

I have these classes:

public class Foo
{
    public Bar bar;
}

public class Bar
{
    public List<int> Something { get; set; }
    public string Else { get; set; }
}

I have a lot of classes like Foo . They all contain exactly one field. This field, Bar in my example, will be a different type of object every time, it doesn't have to be of type Bar . Whatever object it is ( Bar or otherwise), this field will always be an object that has two properties, Something and Else .

My challenge: given any object that's like Foo (with one Field that holds two properties), get the value of the two properties. Given this method:

public void DoStuff(object myObject)
{
    var asdf = myObject.GetType().GetFields().First();
}

I can get the FieldInfo for Bar. What I'm looking for is the values of Something and Else . The names of these properties never change. Whatever the type is of the Field, it will always have two properties named Something and Else that will be of the same type.

Sadly, my problem involves auto generated code, and there are no shared interfaces or base types I can easily use.

Answer 1

Using this code you can retrieve the PropertyInfo s for the Something and for the Else property:

Foo myObject = new Foo { bar = new Bar() };

// the FieldInfo for Foo.bar
var barField = myObject.GetType().GetFields().First();

// the Bar instance, i.e. myObject.bar
var barValue = barField.GetValue(myObject);

var somethingProperty = barField.FieldType.GetProperty("Something", BindingFlags.Instance | BindingFlags.Public);
var elseProperty = barField.FieldType.GetProperty("Else", BindingFlags.Instance | BindingFlags.Public);

as PsiHamster noted, you can then use GetValue and SetValue to retrieve and set the values of somethingProperty and elseProperty like this:

// get the value
var somethingValue = somethingProperty.GetValue(barValue);

// set the value
somethingProperty.SetValue(barValue, new List<int>());

Answer 2

//Get Bar FieldInfo
var barFieldInfo = myObject.GetType().GetFields().First();

// Get all public instance properties info
var barProps = barFieldInfo.FieldType.GetProperties(System.Reflection.BindingFlags.Public | System.Reflection.BindingFlags.Instance);

// Get Something and Else properties info
var smthPropInfo = barProps.First(prop => prop.Name == nameof(Bar.Something));
var elsePropInfo = barProps.First(prop => prop.Name == nameof(Bar.Else));

// Get values
var bar = barFieldInfo.GetValue(myObject);
var smth = smthPropInfo.GetValue(bar);
var else = elsePropInfo.GetValue(bar);