I'm wanting to make a small and simple mobile app for a school project, I know connecting to a db from a phone is not good for security reasons but basically only I will touch it.
So to connect my Xamarin app to Mysql I downloaded the extension MysqlConnector (https://www.nuget.org/packages/MySqlConnector/2.1.8?_src=template)
Everything seemed to work at first, but now I think that there is a problem in their library that is not compatible with Xamarin:
I seem to always get a nullreference exception at the second query at line
reader = cmd.ExecuteReader();. I don't know why, nothing is null, I've printed everything.
(I've put a comment on the line where it happens) I seriously doubt it is a problem in their library since they have 37.2M downloads in total. But maybe it is just a compatability conflict, but that makes it odd that the first query works then.
Here is all my current code:
using PuppyChinoBestelling.Views;
using System;
using System.Collections.Generic;
using System.Text;
using Xamarin.Forms;
using MySqlConnector;
using System.Threading.Tasks;
namespace PuppyChinoBestelling.ViewModels
{
public class LoginViewModel : BaseViewModel
{
public Command LoginCommand { get; }
public string Mail { get; set; }
public string Pass { get; set; }
public LoginViewModel()
{
Pass = string.Empty;
Mail = string.Empty;
LoginCommand = new Command(OnLoginClicked);
}
private async void OnLoginClicked(object obj)
{
MySqlConnection conn = new MySqlConnection("private");
try
{
conn.Open();
Console.WriteLine("Conn opened!");
}
catch(Exception ex)
{
Console.WriteLine("Error " + ex.Message);
}
string sql = #"SELECT * FROM users WHERE email = #email;";
var cmd = conn.CreateCommand();
cmd.CommandText = sql;
cmd.Parameters.AddWithValue("#email", Mail);
var reader = cmd.ExecuteReader();
if (reader.HasRows)
{
sql = #"SELECT * FROM users WHERE email = #email;";
cmd = conn.CreateCommand();
cmd.Parameters.Clear();
cmd.CommandText = sql;
cmd.Parameters.AddWithValue("#email", Mail);
reader = cmd.ExecuteReader(); //null reference happening here idk why
string pwdHashed = reader.GetString(5);
bool validPwd = BCrypt.Net.BCrypt.Verify(Pass, pwdHashed);
conn.Close();
if (validPwd)
{
await Shell.Current.GoToAsync($"//{nameof(AboutPage)}");
}
else
{
Console.WriteLine("Foute logingegevens!");
}
}
else
{
Console.WriteLine("Je bestaat niet!");
}
}
}
}
Thanks in advance!
It's hard to say for certain, but it's likely the issue is because you are not closing the reader and command, and you can't have multiple commands on the same connection.
Also, you need to advance the reader using reader.Read.
In any case there is no need to run the command twice in the first place. You already had all the information on the first run.
You also need to dispose everything with using. This automatically closes the connection.
Don't SELECT *, just select the columns you need.
Ideally, you would calculate the hash for the given password, and send it to the database server to check, rather than pulling out the real password hash from the database (could be a security risk).
Don't store hashes as strings. Instead store them as binary with the varbinary data type, and cast to byte[] on the C# side.
Unclear why you are handling errors only for opening the connection, not for executing the command.
private async void OnLoginClicked(object obj)
{
const string sql = #"
SELECT Pass
FROM users
WHERE email = #email;
";
using (var conn = new MySqlConnection("private"))
using (var cmd = new MySqlCommand(sql, conn))
{
try
{
conn.Open();
Console.WriteLine("Conn opened!");
}
catch(Exception ex)
{
Console.WriteLine("Error " + ex.Message);
return; // no point continuing
}
cmd.Parameters.AddWithValue("#email", Mail);
using (var reader = cmd.ExecuteReader())
{
if (!reader.Read())
{
Console.WriteLine("Je bestaat niet!");
return; // no point continuing
}
string pwdHashed = (string)reader["Pass"];
conn.Close();
bool validPwd = BCrypt.Net.BCrypt.Verify(Pass, pwdHashed);
if (validPwd)
{
await Shell.Current.GoToAsync($"//{nameof(AboutPage)}");
}
else
{
Console.WriteLine("Foute logingegevens!");
}
}
}
}
An alternative method is to remove the reader altogether and use ExecuteScalar
private async void OnLoginClicked(object obj)
{
const string sql = #"
SELECT Pass
FROM users
WHERE email = #email;
";
using (var conn = new MySqlConnection("private"))
using (var cmd = new MySqlCommand(sql, conn))
{
try
{
conn.Open();
Console.WriteLine("Conn opened!");
}
catch(Exception ex)
{
Console.WriteLine("Error " + ex.Message);
return; // no point continuing
}
cmd.Parameters.AddWithValue("#email", Mail);
string pwdHashed = cmd.ExecuteScalar() as string;
conn.Close();
if (pwdHashed is null)
{
Console.WriteLine("Je bestaat niet!");
return; // no point continuing
}
bool validPwd = BCrypt.Net.BCrypt.Verify(Pass, pwdHashed);
if (validPwd)
{
await Shell.Current.GoToAsync($"//{nameof(AboutPage)}");
}
else
{
Console.WriteLine("Foute logingegevens!");
}
}
}
Related
I'm new to .net programming and I have a problem writing intput from a form to sql server. Only one record gets written to the database, for the other records it's says "Data not written to database.". Also my cmbbox is not updated after the data is written to the database, though I run method UpdateInitialWeek().
I don't want to write 'spaghetti code' and would love my program to be a structured one. So any advice is greatly appreciated (I already know it's better to use the Entity Framework to deal with data, something I will learn eventually ;)).
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using System.Data.SqlClient;
namespace Write_to_database
{
public partial class WriteToDatabase : Form
{
SqlServer sql = new SqlServer();
public WriteToDatabase()
{
sql.OpenSqlConnection();
InitializeComponent();
this.UpdateInitialWeek();
sql.CloseSqlConnection();
}
private void btnWrite_Click(object sender, EventArgs e)
{
WriteToOutput(sql.OpenSqlConnection());
if (txtMilitaryPress.Text != "")
WriteToOutput(sql.InsertToTraining(ConvertDate(dtMilitaryPress.Value), "Military Press", txtMilitaryPress.Text.ToString(), txtRepMilitaryPress.Text.ToString(), cmbMilitaryPress.Text.ToString()));
if (txtDeadlift.Text != "")
WriteToOutput(sql.InsertToTraining(dtDeadlift.Value.ToString(), "Deadlift", txtDeadlift.Text.ToString(), txtRepDeadlift.Text.ToString(), cmbDeadlift.Text.ToString()));
if (txtBenchPress.Text != "")
WriteToOutput(sql.InsertToTraining(dtBenchPress.Value.ToString(), "Bench Press", txtBenchPress.Text.ToString(), txtRepBenchPress.Text.ToString(), cmbBenchPress.Text.ToString()));
if (txtBackSquat.Text != "")
WriteToOutput(sql.InsertToTraining(dtBackSquat.Value.ToString(), "Back Squat", txtBackSquat.Text.ToString(), txtRepBackSquat.Text.ToString(), cmbBackSquat.Text.ToString()));
this.UpdateInitialWeek();
WriteToOutput(sql.CloseSqlConnection());
}
//Write output to textbox
public void WriteToOutput(string output)
{
this.txtOutput.AppendText(output + Environment.NewLine);
}
//Convert date for sql server
public string ConvertDate(DateTime date)
{
return date.ToString("MM/dd/yyyy");
}
//Update comboboxes to set right training week
public void UpdateInitialWeek()
{
this.cmbBackSquat.Text = CheckWeek(sql.GetDataTraining("Back Squat"));
this.cmbBenchPress.Text = CheckWeek(sql.GetDataTraining("Bench Press"));
this.cmbDeadlift.Text = CheckWeek(sql.GetDataTraining("Deadlift"));
this.cmbMilitaryPress.Text = CheckWeek(sql.GetDataTraining("Military Press"));
}
//Training week +1 except for week 4 --> back to 1
public string CheckWeek(string trainingWeek)
{
int trWeek = Int32.Parse(trainingWeek);
if (trWeek == 4)
trWeek = 1;
else
trWeek += 1;
return trWeek.ToString();
}
}
public class SqlServer
{
SqlConnection con = new SqlConnection("Data Source=WINSERVER;Initial Catalog=TRAINING;Integrated Security=SSPI;");
public string OpenSqlConnection()
{
try
{
con.Open();
return "Connection to: " + "'Data Source=WINSERVER;Initial Catalog=TRAINING;Integrated Security=SSPI;'" + " successful.";
}
catch
{
return "Connection to: " + "'Data Source=WINSERVER;Initial Catalog=TRAINING;Integrated Security=SSPI;'" + " failed.";
}
}
public string CloseSqlConnection()
{
try
{
con.Close();
return "Connection to: " + "'Data Source=WINSERVER;Initial Catalog=TRAINING;Integrated Security=SSPI;'" + " successfully closed";
}
catch
{
return "Connection to: " + "'Data Source=WINSERVER;Initial Catalog=TRAINING;Integrated Security=SSPI;'" + " not closed.";
}
}
public string InsertToTraining(string date, string lift, string weight, string reps, string week)
{
try
{
using (SqlCommand command = new SqlCommand("INSERT INTO LIFT_HISTORY VALUES(#date,#lift,#weight,#reps,#week)", con))
{
command.Parameters.Add(new SqlParameter("weight", weight.ToString())); //SqlDbType.NVarChar
command.Parameters.Add(new SqlParameter("date", date.ToString()));
command.Parameters.Add(new SqlParameter("week", week.ToString()));
command.Parameters.Add(new SqlParameter("reps", reps.ToString()));
command.Parameters.Add(new SqlParameter("lift", lift.ToString()));
command.ExecuteNonQuery();
}
return "Data successfully written to database.";
}
catch
{
return "Data not written to database.";
}
}
public string GetDataTraining(string where)
{
int trainingWeek;
//using (SqlCommand command = new SqlCommand("SELECT WEEK_OF_TRAINING FROM dbo.LIFT_HISTORY WHERE [DATE] = (SELECT MAX([DATE]) FROM dbo.LIFT_HISTORY WHERE LIFT = 'Deadlift') AND LIFT = 'Deadlift')", con))
using (SqlCommand command = new SqlCommand("SELECT WEEK_OF_TRAINING FROM dbo.LIFT_HISTORY WHERE LIFT = '"+ where +"' ORDER BY [DATE] DESC", con))
{
trainingWeek = (Int32)command.ExecuteScalar();
}
return trainingWeek.ToString();
}
}
}
There are some issues with your code, but it's ok for now that you still learning, for example:
public WriteToDatabase()
{
sql.OpenSqlConnection();
InitializeComponent();
this.UpdateInitialWeek();
sql.CloseSqlConnection();
}
should be:
public void WriteToDatabase()
{
sql.OpenSqlConnection();
InitializeComponent();
this.UpdateInitialWeek();
sql.CloseSqlConnection();
}
That's because you're not returning anything, instead of that you shoud to declare the type of variable that you're returning on.
Well first of all I'd like to suggest you to use a layer-oriented coding. For example:
I'll start crating an entity class:
namespace Entities
{
public class LiftingStory
{
public string Weight { get; set; }
public string Date { get; set; }
public string Week { get; set; }
public string Reps { get; set; }
public string Lift { get; set; }
}
}
Then you start creating "Data-Access" Layer
using System.Data;
using System.Configuration;
using Entities;
namespace DataAccess
{
public class DataLiftingStory
{
public bool insertLifting(LiftingStory obj) //correction: should be LiftingStory instead of DataLiftingStory because I'm retrieving a LiftingStory objecto to be proccesed.
{
//we're creating a new connection to Database, but it will need string parameter
//you can get it directly from the connectionstring on the Web.config in this way
// ConfigurationManager.ConnectionStrings["nameParameterOfYourConnString"].ConnectionString
//instead of that I'll do it with a string for making more easier to understand
string connectionString = "Data Source=WINSERVER;Initial Catalog=TRAINING;Integrated Security=SSPI;";
using (SqlConnection connection = new SqlConnection(connectionString))
{
//now I'll create the command
using (SqlCommand command = new SqlCommand())
{
//so now I've to say what type of command I'm making up. In your case is "Text" because you're being explicit with the query
//I suggest you to use stored procedures btw.
command.CommandType = CommandType.Text;
//now the command text will be your query
command.CommandText = "INSERT INTO LIFT_HISTORY VALUES(#date,#lift,#weight,#reps,#week)";
//now we set the parameters
command.Parameters.Add(new SqlParameter("date", obj.Date));
command.Parameters.Add(new SqlParameter("lift", obj.Lift));
command.Parameters.Add(new SqlParameter("weight", obj.Weight));
command.Parameters.Add(new SqlParameter("reps", obj.Reps));
command.Parameters.Add(new SqlParameter("week", obj.Week));
try
{
command.Connection = connection;
command.Connection.Open();
//now we're executing the query and if we get more than 0 that will means that it inserted or modified a row
//then it will return true and going out from method.
if (command.ExecuteNonQuery() > 0)
return true;
}
catch (Exception)
{
//If it fails return false
return false;
throw;
}
finally
{
//then we close the connection
command.Connection.Close();
}
//if not failed but it didn't anything, it will return false
return false;
}
}
}
Now it's the easy part Business.
using System.Web;
using Entities;
using DataAccess;
namespace Business
{
public class BusinessLiftingStory
{
public bool insertLifting(LiftingStory obj)
{
DataLiftingStory dataLifting = new DataLiftingStory();
dataLifting.insertLifting(obj);
}
}
}
So the last step is to fill the object in the "View-layer" and call the method from Business:
LiftingStory obj = new LiftingStory();
obj.Weight = string.Empty;
obj.Date = string.Empty; //put values from comboBoxes
obj.Reps = string.Empty;
obj.Lift = string.Empty;
obj.Week = string.Empty;
BusinessLiftingStory busObj = new BusinessLiftingStory();
busObj.insertLifting(obj);
Combo boxes are not refreshing data because the DataBind() method, dont forget in the moment when you want to "redraw" your comboBox you'll have to set DataSource = null then get the datasource again and then dataBind.
use a method Init() for that if you want.
private void Init()
{
cmbWeight.DataSource = null;
cmbWeight.DataSource = //new Datasource
//dont forget to set the values and text fields
cmbWeight.DataBind();
}
In that way you'll have a order in your code, , I hope it would help you.
Greetings :)
PS: sorry for the extended answer.
maybe try printing out the exception details either to your return string or console, etc.
instead of
catch
{
return "Data not written to database.";
}
..
catch( Exception ex )
{
return "Data not written to database." + ex.Message;
}
..
https://msdn.microsoft.com/en-us/library/system.exception.message(v=vs.110).aspx
I have multiple databases (30+) that are used at clinics and setup automatically via the license software they use. So each database is named the same and use the same port, the only thing that changes is the IP. That being said, I am using the following code to attempt to run a query against them individually. However, when I change out the IP and run the script again it is returning the results from the previous server.
using System;
using System.Diagnostics;
using System.Data.OleDb;
namespace ConnectionTest
{
class Program
{
static void Main(string[] args)
{
using (OleDbConnection conn = new OleDbConnection("Provider=SAOLEDB.10;LINKS=tcpip(host=X.X.X.X,PORT=2638);ServerName=EAGLESOFT;Integrated Security = True; User ID = dba; PWD = sql"))
{
try
{
conn.Open();
using (OleDbCommand cmd = new OleDbCommand("SELECT tran_num, provider_id, tran_date FROM transactions WHERE tran_date LIKE '2015-11-23%'", conn))
{
using (OleDbDataReader reader = cmd.ExecuteReader())
{
while (reader.Read())
{
Console.WriteLine("{0}|{1}|{2}", reader.GetValue(0).ToString(), reader.GetValue(1).ToString(), reader.GetValue(2).ToString());
}
}
}
}
catch (Exception connerr) { Debug.WriteLine(connerr.Message); }
conn.Close();
}
if (Debugger.IsAttached)
{
Console.ReadLine();
}
}
}
}
I don't see any reason why you would be getting previous results, here. Are you running multiple instances of this code at the same time? Are you manually changing the IP address in your code each time? I assume the "Transactions" object is an actual table and not something being generated on-the-fly?
With just a tiny bit of modification, you could pass the IP address as a command line parameter:
static void Main(string[] args)
{
string ip, port = null;
for (int i = 0; i < args.Length; i++)
{
if (args[i].StartsWith("/i:"))
ip = args[i].Substring(args[i].IndexOf(':') + 1);
else if (args[i].StartsWith("/p:"))
port = args[i].Substring(args[i].IndexOf(':') + 1);
}
// Default the port value to 2638 (since I have no idea if that changes).
if (string.IsNullOrEmpty(port))
port = "2638";
string connStr = string.Format("Provider=SAOLEDB.10;LINKS=tcpip(host={0},PORT={1});ServerName=EAGLESOFT;Integrated Security = True; User ID = dba; PWD = sql", ip, port);
using (OleDbConnection conn = new OleDbConnection(connStr))
{
try
{
conn.Open();
if (conn.State != System.Data.ConnectionState.Open)
// You could also implement a WHILE loop with a small delay (~1200ms) and try again to open the connection, with a counter to "fail" after a certain number (like 3) of attempts.
throw new Exception("Unable to open connection to database.");
using (OleDbCommand cmd = new OleDbCommand("SELECT tran_num, provider_id, tran_date FROM transactions WHERE tran_date LIKE '2015-11-23%'", conn))
using (OleDbDataReader reader = cmd.ExecuteReader())
while (reader.Read())
Console.WriteLine("{0}|{1}|{2}", reader.GetValue(0).ToString(), reader.GetValue(1).ToString(), reader.GetValue(2).ToString());
}
catch (Exception connerr)
{ Debug.WriteLine(connerr.Message); }
finally
{ conn.Close(); }
}
if (Debugger.IsAttached)
{
Console.ReadLine();
}
}
First and foremost (for testing purposes, that is) I would probably try removing the ServerName parameter since you're already providing an IP address explicitly.
So your connection string would be:
Provider=SAOLEDB.10;LINKS=tcpip(host=X.X.X.X,PORT=2638);Integrated Security = True; User ID = dba; PWD = sql
Similar to ORA files, DSNs, etc, it almost sounds like you have a server alias configured for EAGLESOFT that may be overwriting the IP preference in your testing.
Make sure you change EagleSoft as well as IP. You have to pass the IP address as an arg[]. Modify code as below to allow the IP to change
string host = "X.X.X.X";
string conStr = string.Format("Provider=SAOLEDB.10;LINKS=tcpip(host={0},PORT=2638);ServerName=EAGLESOFT;Integrated Security = True; User ID = dba; PWD = sql", host);
using (OleDbConnection conn = new OleDbConnection(conStr))
When I start debugging that error shows, and it associted with the line:
textBox1.Text = cmd.ExecuteReader().ToString();
private void Form1_Load(object sender, EventArgs e)
{
SqlConnection conn = new SqlConnection(#"server= M_SHAWAF\ORCHESTRATE; integrated security=true; database=MyData");
try
{
conn.Open();
SqlCommand cmd = new SqlCommand();
cmd = new SqlCommand(#"select MAX(Nodelevel) from Org", conn);
int s = Int32.Parse(cmd.ExecuteScalar().ToString());
for (int i = 0; i <= s; i++)
{
cmd = new SqlCommand(#"select Name from Org where NodeLevel=" + i.ToString(),conn);
textBox1.Text = cmd.ExecuteReader().ToString();
}
}
catch (SqlException ex)
{
MessageBox.Show(ex.Message);
}
finally
{
conn.Close();
}
}
How can I fix that??
You don't need to continually execute readers in order to obtain the next row of data. If all you need to do is to iterate through all row values of Name from table Org, you can execute a single Sql query to return all rows into the reader, and then to traverse the reader, e.g.:
try
{
using (var conn = new SqlConnection(#"..."))
{
conn.Open();
using (var cmd = new SqlCommand(#"select Name from Org", conn))
{
using (var reader = cmd.ExecuteReader())
{
while (reader.Read())
{
textBox1.Text = reader["Name"].ToString();
}
}
}
}
}
catch (SqlException ex)
{
MessageBox.Show(ex.Message);
}
Edit, Re Hierarchical table structures
If you do need to retain separate iterators while navigating through multiple levels of a hierarchy, you will need multiple readers. As per #Philips answer, in order to have more than one active result set per SqlConnection, you'll need to enable MARS (or open multiple connections).
try
{
using (var conn = new SqlConnection(#"...;MultipleActiveResultSets=True"))
using (var cmdOuter = new SqlCommand(#"select distinct NodeLevel from Org", conn))
{
conn.Open();
using (var outerReader = cmd.ExecuteReader())
{
while (outerReader.Read())
{
var nodeLevel = reader.GetInt32(0);
Console.WriteLine("Node Level {0}", nodeLevel);
using (var cmdInner = new SqlCommand(#"select Name from Org WHERE NodeLevel = #NodeLevel", conn))
{
cmdInner.Parameters.AddWithValue("#NodeLevel", nodeLevel);
using (var innerReader = cmdInner.ExecuteReader())
{
while (innerReader.Read())
{
Console.WriteLine("Name: {0}", innerReader.GetString(0));
}
}
}
}
}
}
}
catch (SqlException ex)
{
MessageBox.Show(ex.Message);
}
modify your connection string to allow multiple results :
connectionString="Data source=localhost; initial catalog=Interstone; integrated security=True; multipleactiveresultsets=True;"
scroll to the right for the right information ;-)
But there are lots of alternatives to avoid needing multiple queries at the same time. Each query you issue that is still pending is a resource that is being used at the server which should be minimized.
So first consider algorithms that don't require multiple cursors and if there is no alternative then setup mars.
Reader is the wrong tool
And you do have an open reader
textBox1.Text = cmd.ExecuteScalar();
First of all: I got my code running without using oop. I declared all my variables inside the same class and opened/closed the connection right before and after passing the query to the db. That worked! Now with some new experiences I tried to split my code into different classes. Now it wont work anymore.
It tells me "Connection must be valid and open". Enough text, here's my current code:
Services.cs
public static MySqlConnection conn // Returns the connection itself
{
get
{
MySqlConnection conn = new MySqlConnection(Services.ServerConnection);
return conn;
}
}
public static string ServerConnection // Returns the connectin-string
{
get
{
return String.Format("Server={0};Port=XXXX;Database=xxx;Uid=xxx;password=xxXxxXxXxxXxxXX;", key);
}
}
public static void DB_Select(string s, params List<string>[] lists)
{
try
{
MySqlCommand cmd = conn.CreateCommand();
cmd.CommandType = CommandType.Text;
string command = s;
cmd.CommandText = command;
MySqlDataReader sqlreader = cmd.ExecuteReader();
while (sqlreader.Read())
{
if (sqlreader[0].ToString().Length > 0)
{
for (int i = 0; i < lists.Count(); i++)
{
lists[i].Add(sqlreader[i].ToString());
}
}
else
{
foreach (List<string> save in lists)
{
save.Add("/");
}
}
}
sqlreader.Close();
}
catch (Exception ex)
{
MessageBox.Show("Error while selecting data from database!\nDetails: " + ex);
}
}
LoginForm.cs
private void checkUser(string username, string password)
{
using (Services.conn)
{
Services.conn.Open();
Services.DB_Select("..a short select statement..");
Services.conn.Close();
}
I guess this is all we need. I have shortened my code to get a focus on the problem.
I created Services.cs to get a global way to access the db from all forms without copy&pasting the connection info. Now when I reach my LoginForm.cs it throws an error "Connection must be valid and open". I've already debugged my code. It's all time closed. Even when passing conn.Open() it stays closed. Why?
Another try: I've also tried placing conn.Open() and conn.Close() inside Services.DB_Select(..) at the beginning and end. Same error here.
I have to say: The code worked before and I've used the same connection-string. So the string itself is surely valid.
I appreciate any help given here!
The problem is that you don't store the connection that was returned from your factory property. But don't use a property like a method. Instead use it in this way:
using (var con = Services.conn)
{
Services.conn.Open();
Services.DB_Select("..a short select statement..", con ));
//Services.conn.Close(); unnecessary with using
}
So use the same connection in the using that was returned from the property(or better created in the using) and pass it to the method which uses it. By the way, using a property as factory method is not best practise.
But in my opinion it's much better to create the connection where you use it, best place is in the using statement. And throw the con property to the garbage can, it is pointless and a source for nasty errors.
public static void DB_Select(string s, params List<string>[] lists)
{
try
{
using(var conn = new MySqlConnection(Services.ServerConnection))
{
conn.Open();
MySqlCommand cmd = conn.CreateCommand();
cmd.CommandText = s;
using( var sqlreader = cmd.ExecuteReader())
while (sqlreader.Read())
{
if (sqlreader[0].ToString().Length > 0)
{
for (int i = 0; i < lists.Count(); i++)
{
lists[i].Add(sqlreader[i].ToString());
}
}
else
{
foreach (List<string> save in lists)
{
save.Add("/");
}
}
} // unnecessary to close the connection
} // or the reader with the using-stetement
}
catch (Exception ex)
{
MessageBox.Show("Error while selecting data from database!\nDetails: " + ex);
}
}
Try to restructure your Services class as follows
public static MySqlConnection conn // Returns the connection itself
{
get
{
MySqlConnection conn = new MySqlConnection(Services.ServerConnection);
return conn;
}
}
private static string ServerConnection // Returns the connectin-string - PRIVATE [Improved security]
{
get
{
return String.Format("Server={0};Port=XXXX;Database=xxx;Uid=xxx;password=xxXxxXxXxxXxxXX;", key);
}
}
// Rather than executing result here, return the result to LoginForm - Future improvement
public static void DB_Select(MySqlConnection conn ,string s, params List<string>[] lists)
{
try
{
MySqlCommand cmd = conn.CreateCommand();
cmd.CommandType = CommandType.Text;
string command = s;
cmd.CommandText = command;
MySqlDataReader sqlreader = cmd.ExecuteReader();
while (sqlreader.Read())
{
if (sqlreader[0].ToString().Length > 0)
{
for (int i = 0; i < lists.Count(); i++)
{
lists[i].Add(sqlreader[i].ToString());
}
}
else
{
foreach (List<string> save in lists)
{
save.Add("/");
}
}
}
sqlreader.Close();
}
catch (Exception ex)
{
MessageBox.Show("Error while selecting data from database!\nDetails: " + ex);
}
}
In LoginForm.cs use returning connection and store it there. When you need to execute query, use
MySqlConnection conn=Services.conn(); // Get a new connection
Services.DB_Select(conn,"..a short select statement.."); // Executing requirement
Services.conn.Close();
Additional - I suggest you need to return MySqlDataReader to LoginForm and handle results there
private MySqlConnection _conn;
public MySqlConnection conn // Returns the connection itself
{
get
{
if(_conn == null)
_conn = new MySqlConnection(Services.ServerConnection);
return _conn;
}
}
I have two problems. One is that it is only pulling one row and sending it to ms fax when there are a few hundred to be sent. The other is that it doesn't pull any more after that first and it throws an error. I thought I was closing out my connections. I don't understand what the problem is. I have included the code and error.
Service1.cs
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Diagnostics;
using System.Linq;
using System.ServiceProcess;
using System.Text;
using System.Timers;
using MySql.Data.MySqlClient;
using FAXCOMLib;
using FAXCOMEXLib;
namespace ProcessFaxes
{
public partial class Service1 : ServiceBase
{
public Service1()
{
InitializeComponent();
}
public static Timer timer = new Timer();
protected override void OnStart(string[] args)
{
timer.Elapsed += new ElapsedEventHandler(Tick);
timer.Interval = 600000; // every 10 minutes
timer.Enabled = true;
// Console.ReadLine();
}
protected override void OnStop()
{
}
public static void Tick(object source, ElapsedEventArgs e)
{
string connString = "Server=localhost;Port=3306;Database=communications;Uid=root;password=pass;";
MySqlConnection conn = new MySqlConnection(connString);
MySqlCommand command = conn.CreateCommand();
MySqlConnection connupdate = new MySqlConnection(connString);
MySqlCommand commandupdate = connupdate.CreateCommand();
command.CommandText = "SELECT * FROM outbox WHERE `faxstat` = 'Y' AND `fax` <> '' AND `faxpro` = 'PENDING'";
//command.CommandText = "UPDATE blah blah";
//conn.Open();
//conn.ExecuteNonQuery();
//conn.Close();
try
{
conn.Open();
connupdate.Open();
}
catch (Exception ex)
{
// Console.WriteLine(Ex.Message);
LogException(ex.ToString());
throw; // or whatever you want to do with it
}
MySqlDataReader reader = command.ExecuteReader();
if (reader.HasRows)
{
while (reader.Read())
{
//Console.WriteLine(reader["filepath"].ToString());
SendFax(reader["id"].ToString(), reader["filepath"].ToString(), #"C:\FAXDOC\" + reader["filepath"].ToString(), reader["account"].ToString(), reader["fax"].ToString(), reader["fax_orig"].ToString());
string id = reader["id"].ToString();
commandupdate.CommandText = "UPDATE outbox SET `faxpro` = 'DONE' WHERE `id` = '" + id + "'";
commandupdate.ExecuteNonQuery();
}
}
conn.Close();
connupdate.Close();
}
public static void SendFax(string DocumentId, string DocumentName, string FileName, string RecipientName, string FaxNumber, string RecipientHomePhone2)
{
if (FaxNumber != "")
{
try
{
FAXCOMLib.FaxServer faxServer = new FAXCOMLib.FaxServerClass();
faxServer.Connect(Environment.MachineName);
FAXCOMLib.FaxDoc faxDoc = (FAXCOMLib.FaxDoc)faxServer.CreateDocument(FileName);
faxDoc.RecipientName = RecipientName;
faxDoc.FaxNumber = FaxNumber;
faxDoc.BillingCode = DocumentId;
faxDoc.DisplayName = DocumentName;
faxDoc.RecipientHomePhone = RecipientHomePhone2;
int Response = faxDoc.Send();
faxServer.Disconnect();
}
catch (Exception Ex) {
// Console.WriteLine(Ex.Message);
LogException(Ex.ToString());
throw; // or whatever you want to do with it
}
}
}
public static void LogException(string ErrorDescription)
{
// The name of our log in the event logs
string Log = "Process Faxes";
// Check to see fi the log for AspNetError exists on the machine
// If not, create it
if ((!(EventLog.SourceExists(Log))))
{
EventLog.CreateEventSource(Log, Log);
}
// Now insert your exception information into the AspNetError event log
EventLog logEntry = new EventLog();
logEntry.Source = Log;
logEntry.WriteEntry(ErrorDescription, EventLogEntryType.Error);
}
}
}
error
Event Type: Error
Event Source: Process Faxes
Event Category: None
Event ID: 0
Date: 3/6/2012
Time: 2:01:06 PM
User: N/A
Computer: FAXSERVER
Description:
MySql.Data.MySqlClient.MySqlException (0x80004005): Too many connections
at MySql.Data.MySqlClient.MySqlStream.ReadPacket()
at MySql.Data.MySqlClient.NativeDriver.Open()
at MySql.Data.MySqlClient.Driver.Open()
at MySql.Data.MySqlClient.Driver.Create(MySqlConnectionStringBuilder settings)
at MySql.Data.MySqlClient.MySqlPool.GetPooledConnection()
at MySql.Data.MySqlClient.MySqlPool.TryToGetDriver()
at MySql.Data.MySqlClient.MySqlPool.GetConnection()
at MySql.Data.MySqlClient.MySqlConnection.Open()
at ProcessFaxes.Service1.Tick(Object source, ElapsedEventArgs e) in C:\Documents and Settings\bruser\My Documents\Visual Studio 2010\Projects\ProcessFaxes\ProcessFaxes\Service1.cs:line 56
I think you should refactor a bit. I explained a little in a comment above, but here's how I would change it (I added some comments for you too):
public static void Tick(object source, ElapsedEventArgs e)
{
// Prevent another Tick from happening if this takes longer than 10 minutes
(source as Timer).Enabled = false;
// It would be better practice to put this in a settings or config file
// so you can change it without having to recompile your application
string connString = "Server=localhost;Port=3306;Database=communications;Uid=root;password=pass;";
// I won't change them here, but since these classes implement IDisposable,
// you should be using a using statement around them:
// using (var conn = new MySqlConnection(connString))
// {
// // use conn
// }
MySqlConnection conn = new MySqlConnection(connString);
MySqlCommand command = conn.CreateCommand();
MySqlCommand updateCommand = conn.CreateCommand();
command.CommandText = "SELECT * FROM outbox WHERE `faxstat` = 'Y' AND `fax` <> '' AND `faxpro` = 'PENDING'";
try
{
conn.Open();
MySqlDataReader reader = command.ExecuteReader();
if (reader.HasRows)
{
while (reader.Read())
{
SendFax(reader["id"].ToString(), reader["filepath"].ToString(), #"C:\FAXDOC\" + reader["filepath"].ToString(), reader["account"].ToString(), reader["fax"].ToString(), reader["fax_orig"].ToString());
string id = reader["id"].ToString();
// I would use a prepared statement with either this query
// or a stored procedure with parameters instead of manually
// building this string (more good practice than worrying about
// SQL injection as it's an internal app
updateCommand.CommandText = "UPDATE outbox SET `faxpro` = 'DONE' WHERE `id` = '" + id + "'";
updateCommand.ExecuteNonQuery();
}
}
}
catch (Exception ex)
{
LogException(ex.ToString());
throw;
}
finally
{
// If you're not going to use using-statements, you might want to explicitly
// call dispose on your disposable objects:
// command.Dispose();
// updateCommand.Dispose();
conn.Close();
// conn.Dispose();
}
// Enable the timer again
(source as Timer).Enabled = true;
}
As to why you're only receiving one row when you're expecting many, I suspect your SQL is at fault.
You should not be using a timer.
A timer fires at regular intervals, and does not care if the previous event has completed or not.
Look at using a Background Worker to send your faxes, having it loop over the queue, and then pause when the queue is empty.
The issue lies in your connection object. You have defined a couple of connection objects. You only need one.
Here are the two in question:
MySqlConnection connupdate = new MySqlConnection(connString);
MySqlConnection conn = new MySqlConnection(connString);
Eliminate the connection to one of them.
Here is one way to fix your code:
string connString = "Server=localhost;Port=3306;Database=communications;Uid=root;password=pass;";
using(MySqlConnection conn = new MySQLConnection(connString))
{
using(MySQlCommand command = conn.CreateCommand())
{
command.CommandText = "SELECT ...";
conn.Open();
using(MySqlDataReader reader = command.ExecuteReader())
{
//process rows...
}
}
}