C# Online Compiler | .NET Fiddle

using System;

public interface IWidget
{
    void Render();
}
public interface IButton: IWidget {}
public interface ITextbox: IWidget {}

public class MaterialButton: IButton
{
    public void Render()
    {
        Console.WriteLine("Material Button");
    }
}
public class MaterialTextbox : ITextbox
{
    public void Render()
    {
        Console.WriteLine("Material Textbox");
    }
}

public class AntButton : IButton
{
    public void Render()
    {
        Console.WriteLine("Ant Button");
    }
}
public class AntTextbox: ITextbox
{
    public void Render()
    {
        Console.WriteLine("Ant Textbox");
    }
}

public enum Theme
{
    Material,
    Ant
}

public interface IWidgetFactory
{
    IButton CreateButton();
    ITextbox CreateTextbox();
}

public class MaterialWidgetFactory : IWidgetFactory
{
    public IButton CreateButton()
    {
        return new MaterialButton();
    }

    public ITextbox CreateTextbox()
    {
        return new MaterialTextbox();
    }
}
public class AntWidgetFactory : IWidgetFactory
{
    public IButton CreateButton()
    {
        return new AntButton();
    }

    public ITextbox CreateTextbox()
    {
        return new AntTextbox();
    }
}

public class ContactForm
{
    public void Render(IWidgetFactory widgetFactory) 
    {
        widgetFactory.CreateTextbox().Render();
        widgetFactory.CreateButton().Render();
    }
}

public class Program
{
	public static void Main()
	{
		new ContactForm().Render(new MaterialWidgetFactory());
	}
}
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