c# – .mdf“出现操作系统错误2(系统找不到指定的文件)

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; }
}

我试图使用Entity Framework创建一个新的数据库,但是我总是得到这个异常

Directory lookup for the file “c:usersorendocumentsvisual studio 2012ProjectsResturantSiteResturantSiteApp_DataResturantSite.SiteContext.mdf” failed with the operating system error 2(The system cannot find the file specified.).
CREATE DATABASE failed. Some file names listed could not be created. Check related errors

Line 28: using (var db = new SiteContext())
Line 29: {
Line 30: db.User.Add(u);
Line 31: db.SaveChanges();
Line 32: }

第30行抛出异常

我希望有人能帮忙