c# - c#错误验证电子邮件

Question

我有一个注册窗口表单，如果没有插入电子邮件的其他帐户，它应该在数据库中插入新帐户的数据。问题是每次创建帐户时，即使电子邮件已经在数据库中。

using (SqlConnection conn = new SqlConnection(@"Data Source=(LocalDB)\v11.0;AttachDbFilename=C:\Users\Andrew\Documents\Visual Studio 2013\Projects\j2016\j2016\GOOD_FOOD.mdf;Integrated Security=True"))
{
    conn.Open();
    if(parolaLbl.Text == parolaReLbl.Text)
    {
        SqlCommand command = new SqlCommand("SELECT email FROM Clienti WHERE email = @email", conn);
        command.Parameters.AddWithValue("@email", emailLbl.Text);
        var result = command.ExecuteScalar().ToString();
        if(result != emailLbl.Text)
        {
            command.CommandText = "INSERT INTO Clienti(parola, nume, prenume, adresa, email) VALUES (@parola, @nume, @prenume, @adresa, @email)";
            command.Parameters.AddWithValue("@parola", parolaLbl.Text);
            command.Parameters.AddWithValue("@nume", numeLbl.Text);
            command.Parameters.AddWithValue("@prenume", prenumeLbl.Text);
            command.Parameters.AddWithValue("@adresa", adresaLbl.Text);
            command.ExecuteNonQuery();
            eroareLbl.Text = "Cont creat!";
        }
        else
        {
            eroareLbl.Text = "Email deja existent!";
        }
    }
    else
    {
        eroareLbl.Text = "Parolele nu coincid";
    }
}

标签： c#sqlwinforms