<Window x:Class="Test.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"          
        xmlns:b="http://schemas.microsoft.com/xaml/behaviors"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:noesis="clr-namespace:NoesisGUIExtensions;assembly=Noesis.GUI.Extensions"
        xmlns:local="clr-namespace:Test"
        xmlns:controls="clr-namespace:Test.Controls"
        mc:Ignorable="d"
        Title="MainWindow" Height="850" Width="1200" Background="AliceBlue"
        x:Name="vMain">

    <Window.DataContext>
        <local:MainWindowViewModel />
    </Window.DataContext>

    <StackPanel Orientation="Vertical">
        <ComboBox ItemsSource="{Binding Source}"/>

        <Button Width="100" Height="25" Content="Add combobox" Command="{Binding AddComboCommand}" CommandParameter="{Binding ElementName=ComboBoxContainer}">

        </Button>

        <WrapPanel x:Name="ComboBoxContainer" Orientation="Horizontal" >
            
        </WrapPanel>
    </StackPanel>   
</Window>

using System.Text;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;
using Test.Util;

namespace Test
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();
            //myGrid.MaxHeight = System.Windows.SystemParameters.PrimaryScreenHeight / 50;
        }
    }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using Test.Util;

namespace Test
{
    public class MainWindowViewModel
    {
        public ImageSource ImageSource { get; set; }
        public string StringPath { get; set; }
        public List<string> Source { get; set; } = new List<string>() { "Hola", "Adios", "Hasta luego", "Qué tal" };

        public ICommand AddComboCommand { get; set; }

        public MainWindowViewModel()
        {
            StringPath = "pack://application:,,,/Resources/Miguel-Indurain-2.webp"; // Ruta relativa
            ImageSource = new BitmapImage(new Uri(StringPath));

            AddComboCommand = new RelayCommand<WrapPanel>(AddCombo, null);
        }

        private void AddCombo(WrapPanel o)
        {
            ComboBox newComboBox = new ComboBox
            {
                Width = 100,
                Margin = new Thickness(0, 0, 10, 0)
            };

            List<string> items = new List<string> { "Pepito", "Manolito", "Luisito" };
            foreach (var item in items)
            {
                newComboBox.Items.Add(item);
            }

            o.Children.Add(newComboBox);
        }
    }
}