How to assign textbox value to another class in wpf

create the same property in the second class and pass it over in the main class:

public class SecondClass
{
    public string TextBox1Text {  get; set; }
}

public class MainClass
{
    SecondClass sc = new SecondClass();


    public string TextBox1Text
    {   
        get { return textBox1.Text; } 
        set { textBox1.Text = value; } 
    }


    public MainClass
    {   
        sc.TextBox1Text = this.TextBox1Text;
    }
}