Getting attributes of a Model, which is an attribute of another one

So I have this model:

public class User
{
public int Id { get; set; }
public string Username { get; set; }
public byte[] PasswordHash { get; set; } = new byte[0];
public byte[] PasswordSalt { get; set; } = new byte[0];
public Usertype Usertype { get; set; } = Usertype.User;
public Details Details { get; set; }
}

And these are Details:

public class Details
{
public int Id { get; set; }
public string Name { get; set; }
public string Surname { get; set; }
public string Email { get; set; }
public DateTime Birthdate { get; set; }
public string Address { get; set; }
public User User { get; set; }
}

If I want to access to the attributes of Details that are inside User, you usually would do that:

User user = new User(){ Id=1, Username="test"}
Details details = new Details() { Id = 1, Name = "Hello", Surname = "World"
user.Details = details;
//You would access to the attributes like that:
string detailsName = user.Details.Name;
int detailsId = user.Details.Id;

Let's say now I want to access to name and details, but without using the dot '.' .
I have the type Details stored in a variable

var type = details.GetType();

Is there a way to access to the same detailsName and detailsId, without using the dot? Even accessing all the variable would be fine. I want to take all the attributes of the User user that are type of type .

I get access to the 'primitive' attributes in this way

var properties = user.GetType().GetProperties();
foreach(var property in properties) {
...
}

But then when it arrives to the attribute 'Details' is not getting inside properties of course. So here I save the type Details (or whatever, I don't want to be specific Details, I want to it to be automatic with whatever class attribute) in the var type, and I want to be able to navigate inside

EDIT:
Here's the complete code to understand better what I want to do. Basically I want to patch/update an user. But I don't want the 'null' or empty values. And I don't want to check one by one attributes, and don't want to specify the attribute name 'Details', because if one day I want to add another class as attribute, I want to script still work without adding manually names.

var properties = userToUpdate.GetType().GetProperties();
foreach(var property in properties)
{
var value = property.GetValue(userToUpdate);
if(property.PropertyType.IsPrimitive || property.PropertyType == typeof(string))
{
typeof(UserDTO).GetProperty(property.Name)?.SetValue(userDTO, value);
} else
{
Type type = property.GetType();
var classProperties = property.PropertyType.GetProperties();
foreach (var classProperty in classProperties)
{
}
}
}

inside the inner foreach, I have info about the type (Details) and have access to its attributes. Now, how can I set these to the User? I want to access User.Details.attributes but without the dot notation, without telling that its a Detail, but telling its a Type type and without telling the name of the attribute, but telling the attribute is the classProperty inside the foreach

 var properties = user.GetType().GetProperties();
foreach (var property in properties)
{
if (property.Name.Contains("Details"))
{
// User reflection to convert the property to details and access the properties. https://stackoverflow.com/questions/47450592/cannot-convert-type-system-reflection-propertyinfo-to
}
}

You are correct that you can use reflection to get the properties of an object in C#. However, to also get the properties of a nested object (like the Details object in your User object), you need to use recursion, like this:

public static void PrintObjectProperties(object obj)
{
if (obj == null) return;
var properties = obj.GetType().GetProperties();
foreach (var property in properties)
{
var value = property.GetValue(obj);
var type = property.PropertyType;
Console.WriteLine($"Property: {property.Name}, Type: {type.Name}, Value: {value}");
// If the property is a class (except string) and not null, print its properties recursively
if (type.IsClass && !typeof(string).IsAssignableFrom(type) && value != null)
{
PrintObjectProperties(value);
}
}
}

This method will print out the name, type, and value of each property in the given object, as well as the properties of any nested objects. If a property's type is a class (and not a string), it will recursively call PrintObjectProperties() on that property's value.

In your case, you can call this method on your User object to print out its properties and the properties of its Details object:

User user = new User(){ Id=1, Username="test"};
Details details = new Details() { Id = 1, Name = "Hello", Surname = "World" };
user.Details = details;
PrintObjectProperties(user);

This should print out the properties of the User object and the properties of the Details object.

If I understand correctly, you want to update the properties of the User object from the corresponding properties of a UserDTO object. If a property in UserDTO is null, you want to skip it and not update the corresponding property in the User object. Also, you want to handle complex properties (like Details) automatically without having to hard-code property names. Here is how you can do it:

var properties = userToUpdate.GetType().GetProperties();
foreach (var property in properties)
{
var value = property.GetValue(userToUpdate);
if (property.PropertyType.IsPrimitive || property.PropertyType == typeof(string))
{
var newValue = typeof(UserDTO).GetProperty(property.Name)?.GetValue(userDTO);
if(newValue != null)
{
property.SetValue(userToUpdate, newValue);
}
}
else
{
// get the instance of the complex property (like Details) from userToUpdate
var detailsInstance = property.GetValue(userToUpdate);
var classProperties = property.PropertyType.GetProperties();
foreach (var classProperty in classProperties)
{
// get the instance of the complex property (like Details) from userDTO
var dtoDetailsInstance = typeof(UserDTO).GetProperty(property.Name)?.GetValue(userDTO);
if(dtoDetailsInstance != null)
{
var newClassValue = classProperty.GetValue(dtoDetailsInstance);
if(newClassValue != null)
{
classProperty.SetValue(detailsInstance, newClassValue);
}
}
}
}
}

In this code, property.SetValue(userToUpdate, newValue); updates the property of the User object if the corresponding property in UserDTO is not null. classProperty.SetValue(detailsInstance, newClassValue); does the same for properties of complex objects like Details.

Please note that this solution assumes UserDTO has the same structure as User, and the property names match exactly. If that's not the case, you might have to maintain a mapping of User property names to UserDTO property names. Also, this solution does not handle nested complex properties (like if Details itself had another complex property). If you need to handle that, you would need to make the code recursive.

If is not fit to you, just give me some real data, I will make a console app for you with explanation.