Using Reflection to get property value for any object

I was tasked to build a method that would take in any object and a string that specifies the property to be returned.

Let’s say we have a complex object as followed

public class Company
{
    public string Name { get; set; }
    public string ABN { get; set; }
    public int YearFounded { get; set; }
    public int TotalEmployees { get; set; }
    public IEnumerable<string> DepartmentNames { get; set; }
    public IEnumerable<Employee> Employees { get; set; }
    public Employee Ceo { get; set; }
}

public class CorporateGroup
{
    public IEnumerable<Company> Companies { get; set; }
    public string Name { get; set; }
    public Employee Ceo { get; set; }
}

public class Employee
{
    public string FirstName { get; set; }
    public string LastName { get; set; }
}

The sample test object is as followed

var corporateGroup = new CorporateGroup
{
    Name = "ABC",
    Ceo = new Employee { FirstName = "John", LastName = "Nerks" },
    Companies = new[] {
        new Company { Name = "SAMPLE", YearFounded = 2017, TotalEmployees = 10,
            DepartmentNames = new[] { "IT", "Accounting" },
            Employees = new[] {
                new Employee { FirstName = "QWERTY", LastName = "OPI" },
                new Employee { FirstName = "ZXCV", LastName = "BNM" },
                new Employee { FirstName = "FGH", LastName = "RTE" },
                new Employee { FirstName = "VCB", LastName = "JKG" }
            },
            Ceo = new Employee { FirstName = "HGJ", LastName = "KLJ" },
            ABN = "ABCDEFG"
        },
        new Company { Name = "XYZ", YearFounded = 2018, TotalEmployees = 15,
            DepartmentNames = new[] { "Finance", "Marketing" },
            Employees = new[] { 
                new Employee { FirstName = "KLJ", LastName = "SFD" }, 
                new Employee { FirstName = "NMB", LastName = "JKH" } },
            Ceo = new Employee { FirstName = "ZXC", LastName = "UYTR" }
        }
    }
};

So if the property string is “ceo.firstname” then the result should be John. Or a more complex one “companies[].employees[].firstName” should return  “QWERTY“, “ZXCV“,“FGH“, “VCB“,“KLJ“, and “NMB“.

I decided to create an extension method for type object. Below is my implementation

public static object GetPropertyValue(this object value, string propertyName)
{
    var nameParts = propertyName.Split('.');
    var isObjectCollection = false;

    foreach (var part in nameParts)
    {
        if (value == null)
        {
            return null;
        }

        var propertyPartName = part.Contains("[") ? part.Split('[')[0] : part;
        var type = value.GetType();
        isObjectCollection = isObjectCollection || type.IsArray || type.GenericTypeArguments.Any();

        if (isObjectCollection)
        {
            value = value.GetCollectionPropertyValue(propertyPartName)
        }
        else
        {
            var propertyInfo = type.GetProperty(propertyPartName, BindingFlags.IgnoreCase | BindingFlags.Public | BindingFlags.Instance);
            if (propertyInfo == null)
            {
                return null;
            }
         
                value = propertyInfo.GetValue(value);
        }
    }

    return value;
}

public static object GetCollectionPropertyValue(this object value, string propertyName)
{
    if (value == null)
    {
        return null;
    }

    if (((IList)value).Count == 0)
    {
        return new List<object>();
    }

    var name = propertyName.Contains("[") ? propertyName.Split('[')[0] : propertyName;
    var type = ((IList)value)[0].GetType();
    var propertyInfo = type.GetProperty(name, BindingFlags.IgnoreCase | BindingFlags.Public | BindingFlags.Instance);

    if (propertyInfo == null)
    {
        return null;
    }

    var valueList = (from object listItem in (IList)value
                     select propertyInfo.GetValue(listItem))
                     .Where(x => x != null).ToList();

    if (valueList.Any())
    {
        var itemType = valueList[0].GetType();

        // Flatten the list if list item is a collection
        if (itemType.IsArray || itemType.GenericTypeArguments.Any())
        {
            valueList = valueList.SelectMany(x => (from object listItem in (IList)x select listItem)).ToList();
        }
    }   

    return valueList;
}