.mdf操作系统错误2失败(系统无法找到指定的文件)。

    protected void register_Click(object sender, EventArgs e)
    {
        AddUser(userName.Text, password.Text, confirm.Text);
    }

    void AddUser(string name, string pass, string confirm)
    {
        User u = new User(name, pass, confirm);

        if (u.Valid)
        {
            using (var db  = new SiteContext())
            {
                db.User.Add(u);
                db.SaveChanges(); 
            }
        }
    }
}

public class User 
{
    public int UserId { get; set; }
    public string UserName { get; set; }
    public string Password { get; set; }
    public bool Valid { get; set; }

    public User(string _name,string _password,string _confirm)
    {
        if (CheckPassword(_password, _confirm))
        {
            Password = _password;
            UserName = _name;
            Valid = true;
        }
        else
            Valid = false;
    }

    private bool CheckPassword(string _password, string _confirm)
    {
        if (_confirm.Equals(_confirm))
            return true;
        return false;
    }
}

public class SiteContext : DbContext 
{
    public DbSet<User> User { get; set; }
}
    protected void register_Click(object sender