C# window application : How to pass the value from one page to another

//In Mdi Form
//Declare the variable, which you want to pass

string userid;
string password;

FormName obj = new FormName(userid,password);
obj.MdiParent = this;
obj.Show();

//In Other Form
//Declare the variable, which you want to pass

string userid;
string password;

public FormName(string uid1,string psw)
{
userid = uid1;
password = psw;
InitializeComponent();
}