c# 4.0 -获取对象的所有属性，这些属性是一个对象的基础

Question

    class Employee
    {
        public string EmployeeId;
        public UserGroup[] UserGroups;
        public Department Department;
        public List<Address> Address;
    }
    class UserGroup
    {
        public int GroupId;
        public string GroupName;
        public string UserName;
        public string Password;
    }
    public class Department
    {
        public int DeptId;
        public string DeptName;
    }
    public class Address
    {
        public string Street;
        public string ZipCode;
        public decimal Latitude;
        public decimal Longitude;
    }
    /// <summary>
    /// This method should loop and read all the properties of Employee object and and assign value to that property
    /// Ex: if propertyName is EmployeeId, propertyValue must be assigned to it.
    /// Ex: if propertyName is GroupName, propertyValue must be assigned to it.
    /// Ex: if propertyName is DeptName, propertyValue must be assigned to it.
    /// Ex: if propertyName is Latitude, propertyValue must be assigned to it.
    /// </summary>
    /// <param name="obj"></param>
    /// <param name="propertyName"></param>
    /// <param name="propertyValue"></param>
    public static AssignValueToProperty(Employee obj, string propertyName, string propertyValue)
    {
        //Implementation Pending
    }

给定Employee对象、PropertyName和PropertyValue，我应该能够遍历其内部对象的所有属性并为该属性赋值。有人能帮我一下吗?

Answer 1

在 c#中可以使用反射来访问对象属性。. NET以及get和set值对该属性。

我想你正在找这样的东西。

考虑给定的Employee对象

    class Employee
    {
        public string EmployeeId;
        public UserGroup[] UserGroups;
        public Department Department;
        public List<Address> Address;
    }

要循环遍历对象的所有属性。你可以这样做:

Employee objEmp = new Employee();
//loop
foreach(var property in objEmp.GetType().GetProperties())
{
   AssignValueToProperty(objEmp, property.Name, "{Your Value}");
}

然后在你的AssignValueToProperty方法中你会得到类似

的东西

public static AssignValueToProperty(Employee obj, string propertyName, string propertyValue)
{
    objEmp.GetType().GetProperty(propertyName).SetValue(objEmp, propertyValue, null);
}

此外，我想补充的是，你有对象结构的属性，如UserGroup[] UserGroups，其中UserGroup是另一个对象。你不认为你的AssignValueToProperty方法不会在这里工作，因为它接受属性值作为字符串数据类型，而你在Employee对象中有不同的数据类型。因此，您所要做的就是像上面给出的那样循环遍历多个对象属性，并最终将它们设置为employee对象。

您也可以通过检查它们的datatypes来设置对象。。

foreach(var property in objEmp.GetType().GetProperties())
{
   // Get PropertyType
   string datatype = property.PropertyType.Name;
   // Apply conditions on the datatype basis
   if (datatype.Equals("string") && property.Name.Equals("EmployeeId"))
   {
      // assign string values
      objEmp.GetType().GetProperty(property.Name).SetValue(objEmp, "{your string value}", null);
   }
   else if (datatype.Equals("UserGroup") && property.Name.Equals("UserGroups"))
   {
      // assign object value
      objEmp.GetType().GetProperty(property.Name).SetValue(objEmp, "{your UserGroup Object}", null);
   }
   // so on other properties
}
// And Finally Use `objEmployee` with all properties values set.

还可以使用lambda表达式查找和设置属性，如下所示:

objEmp.GetType().GetProperties().Where(x => x.Name.Equals("{PropertyName}") && x.PropertyType.Name.Equals("{Target datatype}")).FirstOrDefault().SetValue({Your Object}, {Your Value}, null);

如果你需要在运行时创建一个类对象，那么方法定义将如下:

public static AssignValueToProperty(string obj, string propertyName, string propertyValue)
{
    Type type = Type.GetType(obj, true);
    object objEmp = Activator.CreateInstance(type);
    objEmp.GetType().GetProperty(propertyName).SetValue(objEmp, propertyValue, null);
}

Hope That help…:)