//@nuget: Mapster -Version 7.3.0 

using System;

using Mapster;

using System.Collections.Generic;

using System.Collections;

using System.Linq;

​

public class Program

{

    public static void Main()

    {

        Console.WriteLine("Update an existing object");

        Test1();

    }

​

    static void Test1()

    {

        bool validMembers(object sourceValue)

        {       

             if (sourceValue is null) return false;       

        switch (sourceValue)

        {

            //ignore string.IsNullOrEmpty(x)

            case string { Length: > 0 }:                

                return true;

            //ignore empty collection

            case ICollection { Count: > 0 } l:

                return true;

            case bool b:

                return b;  

            case int i:

                return i != 0;

            //empty collection, empty string

            default:

                return false;

        }

    }

        //the object that is required to be updated:

        var destination = new Foo{Name = "bar"}; //actually it's created from json string.

        //the source object used to update destination object.

        var source = new Foo{Name="", Address="city", Kind = Kind.Male, Cert = new List<string>() {"c1", "c2"}};

        Console.WriteLine("Destination before update:");

        Console.WriteLine($"\tName: {destination.Name}, Address: {destination.Address}  kind: {destination.Kind} Cert couunt: {destination.Cert?.Count()}");

        //update destination object using Mapster

        TypeAdapterConfig.GlobalSettings.Default

           .IgnoreMember((member, side) => validMembers(member)); //??What the parameter that should be passed and have the value of member !!!

        TypeAdapterConfig<Foo, Foo>

            .NewConfig()    

            .IgnoreNullValues(true)             

        ;

        //Mapping to an existing object

        source.Adapt(destination);

        Console.WriteLine("Destination After update:");

        Console.WriteLine($"\tName: {destination.Name}, Address: {destination.Address},   kind: {destination.Kind}, Cert couunt: {destination.Cert.Count()}");

    //should:  Name: bar, Address: city,   kind: Male, Cert couunt: 2

​

    }

}

​

class Foo

{

    public string Name { get; set; }

    public string Address { get; set; }

    public Kind Kind { get; set; }

​

    public IEnumerable<string> Cert { get; set; }

}

​

enum Kind

{

    UnDefined,

    Male,

    Female

}