Şafak Ünel (Matematik Mühendisi)

using System;
using System.Windows.Forms;

namespace WindowsApplication1
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            string str1 = null;
            string str2 = null;

            str1 = "I.String,";
            str2 = "II.String";
            MessageBox.Show(string.Concat(str1, str2)); 
        }
    }
}