using variable content

MessageBox.Show(clsVariable.+"account."+textBox1.Text);

namespace test
{
    public partial class clsVariable
    {
        private static string a7;
        public static string account1 { get { return a7; } set { a7 = value; } }
        private static string a8;
        public static string account2 { get { return a8; } set { a8 = value; } }
        private static string a9;
        public static string account3 { get { return a9; } set { a9 = value; } }
    }

    public partial class Form1 : Form
    {  public Form1()  {  InitializeComponent(); }
         private void Form1_Load(object sender, EventArgs e)
        {
            clsVariable.account1 = "111";
            clsVariable.account2 = "222";
            clsVariable.account3 = "333";
        }
 
        private void button1_Click(object sender, EventArgs e)
        {
            MessageBox.Show(clsVariable.+"account."+textBox1.Text);
        }
    }
}