I need register the user access on my webpage aspx in MySQL remote Database.
But this MySQL remote Database it could be unavailable.
I have tried this code, but how to execute the RegisterUSer() method in the bool IsServerConnected() method ?
public bool IsServerConnected()
{
using (var l_oConnection =
new OdbcConnection(ConfigurationManager.ConnectionStrings["ConnMySQL"].ConnectionString))
{
try
{
l_oConnection.Open();
return true;
}
catch (OdbcException)
{
return false;
}
}
}
private void RegisterUSer()
{
using (OdbcConnection myConnectionString =
new OdbcConnection(ConfigurationManager.ConnectionStrings["ConnMySQL"].ConnectionString))
{
string sql = #String.Format(" INSERT IGNORE INTO tbl_user ");
sql += String.Format(" ... ");
using (OdbcCommand command =
new OdbcCommand(sql, myConnectionString))
{
try
{
command.Connection.Open();
command.ExecuteNonQuery();
}
catch (Exception ex)
{
throw ex;
}
finally
{
command.Connection.Close();
}
}
#Edit 01
Error :
The type or namespace name 'resultType' could not be found (are you
missing a using directive or an assembly reference?)
You could just do a "wrapper" method that calls first to IsServerConnected() and depending on the returned boolean then calls RegisterUSer() or throws an error if the database is not availiable.
Quick and dirty pseudocode
private resultType ChickenWrapMethod()
{
if (!IsServerConnected())
{
//Throw some error here and exit
}
RegisterUSer()
}
BTW...in my opinion you should consider opening the sql connection out of the methods so it can be shared by both operations
Try this in c#. I hope I was helpful.
using System.Net.NetworkInformation;
var ping = new Ping();
var reply = ping.Send("XX.XX.XX.XXX", 60 * 1000); // 1 minute time out (in ms)
if (reply.Status == IPStatus.Success)
{
Response.Write("Server XX.XX.XX.XXX is up");
RegisterUSer();
}
else
{
Response.Write("Server XX.XX.XX.XXX is down");
}
Related
I am building a C# WinUI 3 desktop app running on Windows 10. I want to use a contentdialog to display error messages.
I am calling this method from multiple catch clauses:
private async void DisplayErrorDialog(string content)
{
ContentDialog ErrorDialog = new ContentDialog()
{
Title = "* Error *",
Content = content,
CloseButtonText = "Ok"
};
// XamlRoot must be set in the case of a ContentDialog running in a Desktop app
ErrorDialog.XamlRoot = this.Content.XamlRoot;
ContentDialogResult result = await ErrorDialog.ShowAsync();
}
Here is how I call the method:
catch (SqlException Sql_Error)
{
Debug.WriteLine($"Hello SQL error GetSQLData_App_View_Results_2020: {Sql_Error.Message}");
DisplayErrorDialog($"GetSQLData_App_View_Results_2020 (SQL Error): {Sql_Error.Message}");
}
catch (Exception Other_Error)
{
Debug.WriteLine($"Hello Other error GetSQLData_App_View_Results_2020: {Other_Error.Message}");
DisplayErrorDialog($"GetSQLData_App_View_Results_2020 (Other Error): {Other_Error.Message}");
}
}
I have many other contentdialogs working successfully within my application. I wanted/needed to test this error contentdialog so I explicitly threw an exception this way:
throw new Exception("SQL test exception #1");
The throw does work and the catch clause 'catches' the exception. However I am getting this error in the contentdialog:
Exception thrown at 0x00007FFFD5FE3FA9 (KernelBase.dll) in MetricReporting.exe: WinRT originate error - 0x80070057 : 'This element is already associated with a XamlRoot, it cannot be associated with a different one until it is removed from the previous XamlRoot.'.
I cannot figure this out. I am a beginner C# and WinUI 3 developer. Thank you for your help and guidance.
Thank you Andrew for your observation.
Here is more of my code:
public pageResults()
{
this.InitializeComponent();
Debug.WriteLine($"### --- InitializeComponents() Completed --- ###");
FetchSQLData_Ref_Metric();
FetchSQLData_Ref_Metric_MarketID();
FetchSQLData_StateCodes();
FetchSQLData_MetricYear();
FetchSQLData_Results();
Display_Results();
}
I am doing a lot of sql fetching of data into datatables and then I display the datatable in a datagrid on the page, which is part of a navigationview.
I inserted the 'throw' inside of a method that is inside of 'FetchSQLData_Results()'
private void FetchSQLData_Results()
{
string metricYear = string.Empty;
// Pre-load all views into their own separate datatables. Each views represents a metric year.
// At this time there are views for 2020, 2021, and 2022
foreach (DataRow row in dtMetricYear.Rows)
{
metricYear = row["metricyear"].ToString();
GetSQLData_App_View_Results_(metricYear);
}
}
private void GetSQLData_App_View_Results_(string metricYear)
{
// Load datatables with existing views
switch (metricYear)
{
case "2020":
GetSQLData_App_View_Results_2020();
break;
case "2021":
GetSQLData_App_View_Results_2021();
break;
case "2022":
GetSQLData_App_View_Results_2022();
break;
case "2023":
break;
case "2024":
break;
default:
break;
}
}
The throw is here:
public void GetSQLData_App_View_Results_2020()
{
try
{
using (SqlConnection con = new SqlConnection("Data Source = xxxx; Initial Catalog = xxxx; Integrated Security = True; Connect Timeout = 15; Encrypt = False; TrustServerCertificate = True; ApplicationIntent = ReadWrite; MultiSubnetFailover = False"))
{
**//throw new Exception("SQL test exception #1");**
//Prepare sql
//string sql = "select * from dbo.app_emb_prd_lvl_results_2020 order by metric_id";
string sql = "select * from app_emb_prd_lvl_results_2020 v join dbo.Ref_Metric r on v.metric_id = r.Metric_ID order by v.metric_id";
SqlCommand cmd = new SqlCommand(sql, con);
cmd.CommandType = System.Data.CommandType.Text;
//Open the connection
con.Open();
// Create adapter and fill the datatable with returned data from sql command
using (SqlDataAdapter adap = new SqlDataAdapter(cmd))
{
dtResults2020.Clear();
adap.Fill(dtResults2020);
try
{.. intentionally left blank ..}
catch (Exception List_Error)
{
Debug.WriteLine($"List error GetSQLData_App_View_Results_2020: {List_Error.Message}");
}
Debug.WriteLine($"GetSQLData_App_View_Results_2020 Completed");
} // end using sql adapter
} // end using sql connection
}
catch (SqlException Sql_Error)
{
Debug.WriteLine($"Hello SQL error GetSQLData_App_View_Results_2020: {Sql_Error.Message}");
DisplayErrorDialog($"GetSQLData_App_View_Results_2020 (SQL Error): {Sql_Error.Message}");
}
catch (Exception Other_Error)
{
Debug.WriteLine($"Hello Other error GetSQLData_App_View_Results_2020: {Other_Error.Message}");
DisplayErrorDialog($"GetSQLData_App_View_Results_2020 (Other Error): {Other_Error.Message}");
}
}
As I mentioned in the comments, XamlRoad might not be ready. Try fetching your data in Loaded instead of the constructor.
public pageResults()
{
this.InitializeComponent();
this.Loaded += pageResults_Loaded;
Debug.WriteLine($"### --- InitializeComponents() Completed --- ###");
}
private void pageResults_Loaded(object sender, RoutedEventArgs e)
{
FetchSQLData_Ref_Metric();
FetchSQLData_Ref_Metric_MarketID();
FetchSQLData_StateCodes();
FetchSQLData_MetricYear();
FetchSQLData_Results();
Display_Results();
}
I'm trying to enable/disable my PPPoE adapter according to this answer.
It works great with normal adapters but not with PPPoE which throws an error saying :
An error occurred while querying for WMI data: Invalid method Parameter(s)
The adapter name is correct I used WMI Query tool for that purpose but I have no idea what params need to be set. Any help would be much appreciated.
Edit
Here's the code I used:
static void Main(string[] args)
{
try
{
ManagementObjectSearcher searcher =
new ManagementObjectSearcher("root\\CIMV2",
"SELECT * FROM Win32_NetworkAdapter WHERE Name = 'WAN Miniport (PPPOE)'");
foreach (ManagementObject queryObj in searcher.Get())
{
queryObj.InvokeMethod("Enable", null);
//Console.WriteLine("Name: {0}", queryObj["Name"]);
}
}
catch (ManagementException e)
{
Console.WriteLine("An error occurred while querying for WMI data: " + e.Message);
}
Console.ReadKey();
}
Ok I've found my way around with DotRas here's the code to connect/disconnect PPPoE connection (AKA dial up):
using System;
using System.Linq;
using System.Net;
using DotRas;
namespace Test_Reconnect_PPPoE
{
class Program
{
public static void Main(string[] args)
{
// Connect
using (RasDialer dialer = new RasDialer())
{
dialer.EntryName = "Your Entry (Connection Name)";
dialer.PhoneBookPath = RasPhoneBook.GetPhoneBookPath(RasPhoneBookType.User);
dialer.Credentials = new NetworkCredential("username", "password");
dialer.Dial();
Console.WriteLine("Connected");
}
// Disconnect
RasConnection conn = RasConnection.GetActiveConnections().Where(o => o.EntryName == "Your Entry (Connection Name)").FirstOrDefault();
if (conn != null)
{
conn.HangUp();
Console.WriteLine("Disconnected");
}
Console.ReadKey();
}
}
}
Hope this will help someone.
Please accept my apologies if I'm getting my verbiage wrong; I'm just now learning C# (my background is mostly Visual Basic and PHP).
What I'm trying to do is create a class / routine in C# (Windows Forms) for connecting and disconnecting to a MySQL database that can then be reused throughout the rest of my project without having to reiterate the code every time.
I've got my class / routine setup, but I'm stuck on trying to call it from the rest of my project. I know in Visual Basic this was a fairly simple task to do, but I just can't seem to figure it out how to do it in C#.
Any suggestions? Thank you in advance.
public void dbDisconnect(object sender, EventArgs e)
{
try
{
MySqlConnection connection = new MySqlConnection(Properties.Settings.Default.mysql_db_conn_string);
connection.Close();
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
}
Here's a method I currently have in my app:
public static MySqlConnection CreateConnection(
string mysqlServer,
string mysqlUser,
string mysqlPassword,
string mysqlDatabase)
{
MySqlConnection mysqlConnection = null;
string mysqlConnectionString = String.Format(
"server={0};uid={1};pwd={2};database={3};DefaultCommandTimeout={4};",
mysqlServer, mysqlUser, mysqlPassword, mysqlDatabase, 120);
/**
** Workaround for MySQL 5.6 bug:
** http://stackoverflow.com/questions/30197699/reading-from-stream-failed-mysql-native-password-error
*/
int tryCounter = 0;
bool isConnected = false;
do
{
tryCounter++;
try
{
mysqlConnection = new MySqlConnection();
mysqlConnection.ConnectionString = mysqlConnectionString;
mysqlConnection.Open();
if (mysqlConnection.State == ConnectionState.Open)
{
isConnected = true;
}
}
catch (MySqlException ex)
{
if (tryCounter < 10)
{
DebugLog.Dump(ex.ToString(), DebugLog.MainLogFilePath);
Thread.Sleep(10000); // 10 seconds.
}
else
{
throw;
}
}
} while (!isConnected);
return mysqlConnection;
}
Usage:
using (MySqlConnection hostsDbConnection = HostsDbConnector.CreateConnection())
{
// Do something...
}
With using keyword you don't need to close the connection manually, it'll be closed automatically when it's no longer needed.
Is it possible for mysql to execute a script even when the connection has been closed?
I am using mysql community server , through a .NET connector API.
Was using c# to test out the API.
I have the following static class
using System;
using System.Data;
using MySql.Data;
using MySql.Data.MySqlClient;
public static class DataBase
{
static string connStr = "server=localhost;user=root;port=3306;password=*******;";
static MySqlConnection conn;
public static bool Connect()
{
conn = new MySqlConnection(connStr);
try
{
conn.Open();
}
catch (Exception Ex)
{
ErrorHandler(Ex);
return false;
}
return true;
}
public static int ExecuteScript(string scripttext) // returns the number of statements executed
{
MySqlCommand cmd = conn.CreateCommand();
cmd.CommandText = scripttext;
MySqlScript script;
int count= 0;
try
{
script = new MySqlScript(conn, cmd.CommandText);
script.Error += new MySqlScriptErrorEventHandler(script_Error);
script.ScriptCompleted += new EventHandler(script_ScriptCompleted);
script.StatementExecuted += new MySqlStatementExecutedEventHandler(script_StatementExecuted);
count = script.Execute();
}
catch (Exception Ex)
{
count = -1;
ErrorHandler(Ex);
}
return count;
}
# region EventHandlers
static void script_StatementExecuted(object sender, MySqlScriptEventArgs args)
{
string Message = "script_StatementExecuted";
}
static void script_ScriptCompleted(object sender, EventArgs e)
{
string Message = "script_ScriptCompleted!";
}
static void script_Error(Object sender, MySqlScriptErrorEventArgs args)
{
string Message = "script_Error: " + args.Exception.ToString();
}
# endregion
public static bool Disconnect()
{
try
{
conn.Close();
}
catch (Exception Ex)
{
ErrorHandler(Ex);
return false;
}
return true;
}
public static void ErrorHandler(Exception Ex)
{
Console.WriteLine(Ex.Source);
Console.WriteLine(Ex.Message);
Console.WriteLine(Ex.ToString());
}
}
and I am using the following code to test out this class
using System;
using System.Data;
namespace Sample
{
public class Sample
{
public static void Main()
{
if (DataBase.Connect() == true)
Console.WriteLine("Connected");
if (DataBase.Disconnect() == true)
Console.WriteLine("Disconnected");
int count = DataBase.ExecuteScript("drop database sample");
if (count != -1)
{
Console.WriteLine(" Sample Script Executed");
Console.WriteLine(count);
}
Console.ReadKey();
}
}
}
I noticed that even though I have closed my MySql connection using Disconnect() - which i have defined, mysql continues to execute the command i give next and no error is generated.
I feel like I am doing something wrong, as an error should be generated when i try to execute a script on a closed connection.
Is it a problem in my code/logic or some flaw in mysql connector?
I did check through the mysql workbench whether the command was executed properly and it was.
This is a decompile of MySqlScript.Execute code....
public unsafe int Execute()
{
......
flag = 0;
if (this.connection != null)
{
goto Label_0015;
}
throw new InvalidOperationException(Resources.ConnectionNotSet);
Label_0015:
if (this.query == null)
{
goto Label_002A;
}
if (this.query.Length != null)
{
goto Label_002C;
}
Label_002A:
return 0;
Label_002C:
if (this.connection.State == 1)
{
goto Label_0047;
}
flag = 1;
this.connection.Open();
....
As you can see, when you build the MySqlScript the connection passed is saved in an internal variable and before executing the script, if the internal connection variable is closed, the code opens it. Not checked but I suppose that it also closes the connection before exiting (notice that flag=1 before opening)
A part from this I suggest to change your code to avoid keeping a global MySqlConnection object. You gain nothing and risk to incur in very difficult bugs to track.
static string connStr = "server=localhost;user=root;port=3306;password=*******;";
public static MySqlConnection Connect()
{
MySqlConnection conn = new MySqlConnection(connStr);
conn.Open();
return conn;
}
This approach allows to write code that use the Using Statement
public static int ExecuteScript(string scripttext) // returns the number of statements executed
{
using(MySqlConnection conn = Database.Connect())
using(MySqlCommand cmd = conn.CreateCommand())
{
cmd.CommandText = scripttext;
....
}
}
The Using statement will close and dispose the connection and the command freeing valuable resources and also in case of exception you will be sure to have the connection closed and disposed
I am trying to verify the backup I have just done in c# using command against sql server Express
string _commandText = string.Format("RESTORE VERIFYONLY FROM DISK = '{0}'", backupLocation);
SqlDataReader _sqlDataReader = SqlHelper.ExecuteReader("BookssortedSQLDbConnection", CommandType.Text, _commandText);
If I execute the command in SSMS it returns 'The backup set on file 1 is valid.' but how can I get this message back into my code?
A reader wont work as there are no rows being returned.
NOTE: I have tried the SMO.Restore object to try and verify it but it doesn't work and that is why I am doing it this way.
_restore.SqlVerify(srv, out _errorMessage); //returns false even though bakcup is fine
BTW - Open to suggestions as I don't think this is the ideal way to achieve what I am trying to do
Informational messages (with severity less than 10) and PRINT output are returned to the client, and raised as InfoMessage events by the SqlConnection instance. Each event contains a collection of SqlError objects (this is the same class used in SqlException.Errors).
Here's a complete example that shows connection state changes, info messages and exceptions. Note that I use ExecuteReader instead of ExecuteNonQuery, but the info and exception results are the same.
namespace Test
{
using System;
using System.Data;
using System.Data.SqlClient;
public class Program
{
public static int Main(string[] args)
{
if (args.Length != 2)
{
Usage();
return 1;
}
var conn = args[0];
var sqlText = args[1];
ShowSqlErrorsAndInfo(conn, sqlText);
return 0;
}
private static void Usage()
{
Console.WriteLine("Usage: sqlServerConnectionString sqlCommand");
Console.WriteLine("");
Console.WriteLine(" example: \"Data Source=.;Integrated Security=true\" \"DBCC CHECKDB\"");
}
public static void ShowSqlErrorsAndInfo(string connectionString, string query)
{
using (SqlConnection connection = new SqlConnection(connectionString))
{
connection.StateChange += OnStateChange;
connection.InfoMessage += OnInfoMessage;
SqlCommand command = new SqlCommand(query, connection);
try
{
command.Connection.Open();
Console.WriteLine("Command execution starting.");
SqlDataReader dr = command.ExecuteReader();
if (dr.HasRows)
{
Console.WriteLine("Rows returned.");
while (dr.Read())
{
for (int idx = 0; idx < dr.FieldCount; idx++)
{
Console.Write("{0} ", dr[idx].ToString());
}
Console.WriteLine();
}
}
Console.WriteLine("Command execution complete.");
}
catch (SqlException ex)
{
DisplaySqlErrors(ex);
}
finally
{
command.Connection.Close();
}
}
}
private static void DisplaySqlErrors(SqlException exception)
{
foreach (SqlError err in exception.Errors)
{
Console.WriteLine("ERROR: {0}", err.Message);
}
}
private static void OnInfoMessage(object sender, SqlInfoMessageEventArgs e)
{
foreach (SqlError info in e.Errors)
{
Console.WriteLine("INFO: {0}", info.Message);
}
}
private static void OnStateChange(object sender, StateChangeEventArgs e)
{
Console.WriteLine("Connection state changed: {0} => {1}", e.OriginalState, e.CurrentState);
}
}
}
Its pretty difficult to retrieve the ssms message to the front end application . However you can write the message into a text file and then read the data from the file .
declare #cmd varchar(1000)
SET #cmd = 'osql -S YourServer -E -d YourDatabase -q "RESTORE VERIFYONLY FROM DISK=''c:\yourBackup.bkp''" -o c:\result.txt'
EXEC master.dbo.xp_cmdshell #cmd
You can execute the above sql statements from your application and then read the result from the result.txt file