使用反射获取嵌套对象属性值

Question

我有以下两个类:

public class Address
{
    public string AddressLine1 { get; set; }
    public string AddressLine2 { get; set; }
    public string City { get; set; }
    public string State { get; set; }
    public string Zip { get; set; }
}

public class Employee
{
    public string FirstName { get; set; }
    public string MiddleName { get; set; }
    public string LastName { get; set; }
    public Address EmployeeAddress { get; set; }
}

我有一个employee类的实例如下:

    var emp1Address = new Address();
    emp1Address.AddressLine1 = "Microsoft Corporation";
    emp1Address.AddressLine2 = "One Microsoft Way";
    emp1Address.City = "Redmond";
    emp1Address.State = "WA";
    emp1Address.Zip = "98052-6399";

    var emp1 = new Employee();
    emp1.FirstName = "Bill";
    emp1.LastName = "Gates";
    emp1.EmployeeAddress = emp1Address;

我有一个方法,它根据属性名称获取属性值,如下所示:

public object GetPropertyValue(object obj ,string propertyName)
{
    var objType = obj.GetType();
    var prop = objType.GetProperty(propertyName);

    return prop.GetValue(obj, null);
}

上面的方法适用于调用,GetPropertyValue(emp1, "FirstName")但如果我尝试GetPropertyValue(emp1, "Address.AddressLine1")它会引发异常,因为objType.GetProperty(propertyName);无法找到嵌套的对象属性值.有没有办法来解决这个问题？

Answer 1

public object GetPropertyValue(object obj, string propertyName)
{
    foreach (var prop in propertyName.Split('.').Select(s => obj.GetType().GetProperty(s)))
       obj = prop.GetValue(obj, null);

    return obj;
}

谢谢,我来到这里寻找同样问题的答案.我最终修改了原始方法以支持嵌套属性.这应该比必须进行嵌套方法调用更加健壮,这可能最终导致超过2个嵌套级别的繁琐.

Answer 2

var address = GetPropertyValue(GetPropertyValue(emp1, "Address"), "AddressLine1");

对象Employee没有名为"Address.AddressLine1"的单个属性,它有一个名为"Address"的属性,该属性本身具有名为"AddressLine1"的属性.

Answer 3

我使用此方法从属性(无限数量的嵌套属性)获取值,如下所示:

"属性"

"街道地址"

"Address.Country.Name"

    public static object GetPropertyValue(object src, string propName)
    {
        if (src == null) throw new ArgumentException("Value cannot be null.", "src");
        if (propName == null) throw new ArgumentException("Value cannot be null.", "propName");

        if(propName.Contains("."))//complex type nested
        {
            var temp = propName.Split(new char[] { '.' }, 2);
            return GetPropertyValue(GetPropertyValue(src, temp[0]), temp[1]);
        }
        else
        {
            var prop = src.GetType().GetProperty(propName);
            return prop != null ? prop.GetValue(src, null) : null;
        }
    }

这里的小提琴:https://dotnetfiddle.net/PvKRH0

Answer 4

这适用于无限数量的嵌套属性.

public object GetPropertyValue(object obj, string propertyName)
{
    var _propertyNames = propertyName.Split('.');

    for (var i = 0; i < _propertyNames.Length; i++)
    {
        if (obj != null)
        {
            var _propertyInfo = obj.GetType().GetProperty(_propertyNames[i]);
            if (_propertyInfo != null)
                obj = _propertyInfo.GetValue(obj);
            else
                obj = null;
        }
    }

    return obj;
}

用法:

GetPropertyValue(_employee, "Firstname");
GetPropertyValue(_employee, "Address.State");
GetPropertyValue(_employee, "Address.Country.Name");