c# - 如何从窗口中的另一个类调用方法？

Question

所以我有一个名为“User”的类，其中有以下方法和代码:

public void Login()
{
   LoginWindow l = new LoginWindow();
   if (l.tbxEmail.Text != "" && l.tbxPassword.Text != "")
   {
      string query = "SELECT * FROM UsersTBL";
      l.con.Open();
      l.com = l.con.CreateCommand();
      l.com.CommandText = query;
      SqlDataReader dr = l.com.ExecuteReader();
      if (dr.Read())
      {
         if (dr["Email"].Equals(l.tbxEmail.Text.ToString()) && dr["UserPassword"].Equals(l.tbxPassword.Text.ToString()))
         {
            AppWindow a = new AppWindow();
            a.Show();
         }
         else
            l.lblMissingParameter.Content = "Incorrect Password or Email entered";
      }
   }
}

在我的 LoginWindow 中我有:

public partial class LoginWindow:Window
{
     User u = new User();
     private void BtnSignup_Click(object sender, RoutedEventArgs e)
     {
         u.Login();
     }
}

当我尝试通过类实例化调用我的登录方法时，没有任何效果，这是为什么？我叫错了吗？

Answer 1

这应该可行，尽管我对应该解决的事情发表了评论。

用户类:

public bool Login(SqlConnection con, string email, string password)
{
    const string query = "SELECT 1 FROM UsersTBL WHERE Email = @email AND UserPassword = @password";
    if (!string.IsNullOrWhiteSpace(email) && !string.IsNullOrWhiteSpace(password))
    {
        try
        {
            con.Open();
            var cmd = con.CreateCommand();
            cmd.CommandText = query;
            //Correct SqlDbTypes if necessary
            cmd.Parameters.Add("@email", SqlDbType.VarChar);
            cmd.Parameters["@email"].Value = email;
            cmd.Parameters.Add("@password", SqlDbType.VarChar);
            //Should NOT be storing passwords as plain text in the database
            cmd.Parameters["@password"].Value = password;
            if (cmd.ExecuteScalar() == 1)
                return true;
        }
        catch (Exception e)
        {
             //log e somehow or eliminate this catch block
        }
        finally
        {
             //Close the connection if still open
             if (con != null && con.State != ConnectionState.Closed)
                 con.Close();
        }
    }
    return false;
}

LoginWindow 类:

public partial class LoginWindow : Window
{
    private void BtnSignup_Click(object sender, RoutedEventArgs e)
    {
        var u = new User();
        if (u.Login(con, tbxEmail.Text, tbxPassword.Text))
        {
            AppWindow a = new AppWindow();
            a.Show();
        }
        else
            lblMissingParameter.Content = "Incorrect Password or Email entered";
    }
}