C# How to acces to Values of an class Object, by an another Class object

Question

I want to assign an object of one class to another class by constructor, and retrieve the values of the class assigned by constructor from the class which has the constructor. Sounds confusing, it is too:). Can't handle it. Do you have any ideas? Here is an example code.

public class Class1
{
   public class1(int value1)
   {
       Value1 = value1;
   }
   public int Value1 { get;}
}

public class Class2
{
   public object Object1 {get; set;}
}

public class main
{

   Class1 TestClass = new Class1(15);
   Class2 TestClass1 = new Class2();

   public void main()
   {
       TestClass1.Object1 = TestClass();

       //Now I want to this
       Console.WriteLine(TestClass1.Object1.Value1);
       TestClass1.Object1.Value1;   
   }
}

Answer 1

For that you need to creare property of that particular type instead of using base object type like:

public class Class2
{
   public Class1 Object1 {get; set;}
}

then you can write:

Class1 TestClass = new Class1(15);
Class2 TestClass1 = new Class2();

public void main()
{
   TestClass1.Object1 = TestClass;

   //Now you can do what you wanted
   Console.WriteLine(TestClass1.Object1.Value1);
}

if you really want to used object type then you will need to cast the object to it's actual type and then you can have the properties available at compile time:

public class Class2
{
   public object Object1 {get; set;}
}

and now:

public void main()
{
   TestClass1.Object1 = TestClass;

   Class1 temp =  TestClass1.Object1 as Class1;
   // safe guard in case cast fails 
   if(temp !=null)
   {
      //Now you can do what you wanted
      Console.WriteLine(temp.Value1);
   }
}

Answer 2

Class stores it's child as object and object doesn't have a property Value1 .

You need to cast the Object1 property or make Class2 generic.

Casting

Class1 o1 = new Class1(15);
Class2 o2 = new Class2();

o2.Object1 = o1;

var x = o2.Object1 as Class1;
//If o2.Object1 is not Class1 x will be null.  

Console.WriteLine(x.Value1); 

Making Class2 generic

public class Class1
{
    public Class1(int value1) { Value1 = value1; }
    public int Value1 { get; set; }
}

public class Class2<T>
{
    public T Object1 { get; set; }
}

public static async Task Main()
{
    var o1 = new Class1(15);
    var o2 = new Class2<Class1>();

    o2.Object1 = o1;

    Console.WriteLine(o2.Object1.Value1);
}

Answer 3

Following approach take nested instance as a constructor parameter whilst constructing outer / container instance.

        public class Inner
        {
            public Inner(int value)
            {
                Value = value;
            }
            public int Value { get; }
        }

        public class Outer
        {
            public Outer(Inner inner)
            {
                InnerObject = inner;
            }
            public Inner InnerObject { get;}
        }

        public class main
        {       

            static void Main()
            {
                var outer = new Outer(new Inner(10));
                Console.WriteLine(outer.InnerObject.Value);
                var value = outer.InnerObject.Value;
            }
        }

Answer 4

Try these two object extension methods for getting and setting values.

Usage;

myObject.SetPropertyByName("MyProperty", "MyValue");

var value = myObject.GetPropertyValueByName("MyProperty");

public static class FwExtensions
{
    /// <summary>
    /// Set the value of a property if it exists and you don't have an interface
    /// </summary>
    /// <param name="me"></param>
    /// <param name="propertyName"></param>
    /// <param name="value"></param>
    /// <returns> true if the value was found and set, else false</returns>
    public static bool SetPropertyByName(this object me, string propertyName, object value)
    {
        if (me != null)
        {
            PropertyInfo prop = me.GetType().GetProperty(propertyName, BindingFlags.Public | BindingFlags.Instance);
            if (null != prop && prop.CanWrite)
            {
                prop.SetValue(me, value, null);
                return true;
            }
        }
        return false;
    }

    public static object GetPropertyValueByName(this object me, string propertyName)
    {
        if (me != null)
        {
            PropertyInfo prop = me.GetType().GetProperty(propertyName, BindingFlags.Public | BindingFlags.Instance);
            if (null != prop && prop.CanWrite)
            {
                return prop.GetValue(me);
            }
        }
        return null;
    }
}