Develop Reference

Parameter '?user_email' not found in the collection

I am using MySql 5.6x with Visual Studio 2015, windows 10, 64-bit. C# as programming language. In my CRUD.cs (Class file) i have created the following method:
public bool dbQuery(string sql,string[] paramList= null)
{
bool flag = false;
try
{
connect();
cmd = new MySqlCommand(sql,con);
cmd.Prepare();
if(paramList != null){
foreach(string i in paramList){
string[] valus = i.Split(',');
string p = valus[0];
string v = valus[1];
cmd.Parameters[p].Value = v;
}
}
if (cmd.ExecuteNonQuery() > 0)
{
flag = true;
}
}
catch (Exception exc)
{
error(exc);
}
}
I am passing the query and Parameters List like this:
protected void loginBtn_Click(object sender, EventArgs e)
{
string sql = "SELECT * FROM dept_login WHERE (user_email = ?user_email OR user_cell = ?user_cell) AND userkey = ?userkey";
string[] param = new string[] {
"?user_email,"+ userid.Text.ToString(),
"?user_cell,"+ userid.Text.ToString(),
"?userkey,"+ userkey.Text.ToString()
};
if (db.dbQuery(sql, param))
{
msg.Text = "Ok";
}
else
{
msg.Text = "<strong class='text-danger'>Authentication Failed</strong>";
}
}
Now the problem is that after the loop iteration complete, it directly jumps to the catch() Block and generate an Exception that:
Parameter '?user_email' not found in the collection.
Am i doing this correct to send params like that? is there any other way to do the same?
Thanks
EDIT: I think the best way might be the two-dimensional array to collect the parameters and their values and loop then within the method to fetch the parameters in cmd.AddWidthValues()? I may be wrong...

In your dbQuery you don't create the parameters collection with the expected names, so you get the error when you try to set a value for a parameter that doesn't exist
public bool dbQuery(string sql,string[] paramList= null)
{
bool flag = false;
try
{
connect();
cmd = new MySqlCommand(sql,con);
cmd.Prepare();
if(paramList != null){
foreach(string i in paramList){
string[] valus = i.Split(',');
string p = valus[0];
string v = valus[1];
cmd.Parameters.AddWithValue(p, v);
}
}
if (cmd.ExecuteNonQuery() > 0)
flag = true;
}
catch (Exception exc)
{
error(exc);
}
}
Of course this will add every parameter with a datatype equals to a string and thus is very prone to errors if your datatable columns are not of string type
A better approach would be this one
List<MySqlParameter> parameters = new List<MySqlParameter>()
{
{new MySqlParameter()
{
ParameterName = "?user_mail",
MySqlDbType= MySqlDbType.VarChar,
Value = userid.Text
},
{new MySqlParameter()
{
ParameterName = "?user_cell",
MySqlDbType= MySqlDbType.VarChar,
Value = userid.Text
},
{new MySqlParameter()
{
ParameterName = "?userkey",
MySqlDbType = MySqlDbType.VarChar,
Value = userkey.Text
},
}
if (db.dbQuery(sql, parameters))
....
and in dbQuery receive the list adding it to the parameters collection
public bool dbQuery(string sql, List<MySqlParameter> paramList= null)
{
bool flag = false;
try
{
connect();
cmd = new MySqlCommand(sql,con);
cmd.Prepare();
if(paramList != null)
cmd.Parameters.AddRange(paramList.ToArray());
if (cmd.ExecuteNonQuery() > 0)
{
flag = true;
}
}
catch (Exception exc)
{
error(exc);
}
}
By the way, unrelated to your actual problem, but your code doesn't seem to close and dispose the connection. This will lead to very nasty problems to diagnose and fix. Try to use the using statement and avoid a global connection variable
EDIT
As you have noticed the ExecuteNonQuery doesn't work with a SELECT statement, you need to use ExecuteReader and check if you get some return value
using(MySqlDataReader reader = cmd.ExecuteReader())
{
flag = reader.HasRows;
}
This, of course, means that you will get troubles when you want to insert, update or delete record where instead you need the ExecuteNonQuery. Creating a general purpose function to handle different kind of query is very difficult and doesn't worth the work and debug required. Better use some kind of well know ORM software like EntityFramework or Dapper.

Your SQL Commands' Parameters collection does not contain those parameters, so you cannot index them in this manner:
cmd.Parameters[p].Value = v;
You need to add them to the Commands' Parameters collection in this manner: cmd.Parameters.AddWithValue(p, v);.

SQL ParameterDirection.InputOutput / SqlCommand.ExecuteNonQuery() error

I have a very strange problem that only occurs when the code in question is in a high load situations. My ASP.NET web client C# code calls a T-SQL stored procedure that has an OUTPUT parameter.
Under high loads, the data being returned sometimes does not make it back to the calling C# code. I have extracted all the relevant code into the example below;
Stored procedure:
CREATE PROCEDURE GetLoginName
#LoginId BIGINT,
#LoginName VARCHAR(50) OUTPUT
AS
SET NOCOUNT ON
SELECT #LoginName = LoginName
FROM Logins
WHERE Id = #LoginId
SET NOCOUNT OFF
GO
Database base class:
public class DatabaseContextBase : IDisposable
{
private SqlConnection _connection;
private string _connectionString;
private SqlInt32 _returnValue;
private int _commandTimeout;
private static int _maxDatabaseExecuteAttempts = 3;
private static int s_commandTimeout = 30;
protected DBContextBase()
{
// try and get the connection string off the identity first...
string connectionString = GetConnectionStringFromIdentity();
if(connectionString != null)
{
ConstructionHelper(connectionString, s_commandTimeout);
}
else
{
// use the initialised static connection string, and call the other overload
// of the constructor
ConstructionHelper(s_connectionString, s_commandTimeout);
}
}
private void ConstructionHelper( string connectionString, int commandTimeout )
{
// store the connection string in a member var.
_connectionString = connectionString;
// store the timeout in a member var.
_commandTimeout = commandTimeout;
}
public static string GetConnectionStringFromIdentity()
{
IIdentity identity = Thread.CurrentPrincipal.Identity as wxyz.Security.wxyzIdentityBase;
string connectionString = null;
if(identity != null)
{
connectionString = ((wxyz.Security.wxyzIdentityBase) identity ).ConnectionString;
}
return connectionString;
}
public void Dispose()
{
if (_connection.State != ConnectionState.Closed)
{
_connection.Close();
}
_connection.Dispose();
_connection = null;
}
protected void ExecuteNonQuery(SqlCommand command)
{
SqlConnection con = this.Connection;
lock (con)
{
if (con.State != ConnectionState.Open)
{
con.Open();
}
// don't need a try catch as this is only ever called from another method in this
// class which will wrap it.
command.Connection = con;
command.Transaction = _transaction;
command.CommandTimeout = _commandTimeout;
for (int currentAttempt = 1; currentAttempt == _maxDatabaseExecuteAttempts; currentAttempt++)
{
try
{
// do it
command.ExecuteNonQuery();
// done, exit loop
break;
}
catch (SqlException sex)
{
HandleDatabaseExceptions(currentAttempt, sex, command.CommandText);
}
}
}
}
protected void HandleDatabaseExceptions(int currentAttempt, SqlException sqlException, string sqlCommandName)
{
if (DataExceptionUtilities.IsDeadlockError(sqlException))
{
if (!this.IsInTransaction)
{
// Not in a transaction and a deadlock detected.
// If we have not exceeded our maximum number of attemps, then try to execute the SQL query again.
string deadlockMessage = string.Format("Deadlock occured in attempt {0} for '{1}':", currentAttempt, sqlCommandName);
Logging.Write(new ErrorLogEntry(deadlockMessage, sqlException));
if (currentAttempt == DBContextBase.MaxDatabaseExecuteAttempts)
{
// This was the last attempt so throw the exception
throw sqlException;
}
// Wait for a short time before trying again
WaitShortAmountOfTime();
}
else
{
// We're in a transaction, then the calling code needs to handle the deadlock
string message = string.Format("Deadlock occured in transaction for '{0}':", sqlCommandName);
throw new DataDeadlockException(message, sqlException);
}
}
else if (this.IsInTransaction && DataExceptionUtilities.IsTimeoutError(sqlException))
{
// We're in a transaction and the calling code needs to handle the timeout
string message = string.Format("Timeout occured in transaction for '{0}':", sqlCommandName);
// Raise a Deadlock exception and the calling code will rollback the transaction
throw new DataDeadlockException(message, sqlException);
}
else
{
// Something else has gone wrong
throw sqlException;
}
}
/// <summary>
/// get the SqlConnection object owned by this database (already connected to db)
/// </summary>
public SqlConnection Connection
{
get {
// check whether we've got a connection string (from either identity or static initialise)
if ( _connectionString == null )
{
throw new ArgumentNullException( "connectionString", "Connection string not set" );
}
if ( _connection != null )
{
return _connection;
}
else
{
_connection = new SqlConnection( _connectionString );
return _connection;
}
}
}
/// <summary>
/// Return value from executed stored procedure
/// </summary>
public SqlInt32 ReturnValue
{
get { return _returnValue; }
set { _returnValue = value; }
}
}
Database access class:
public class AuthenticationDBCommands
{
public static SqlCommand GetLoginName()
{
System.Data.SqlClient.SqlCommand cmd = new System.Data.SqlClient.SqlCommand("GetLoginName");
cmd.CommandType = CommandType.StoredProcedure;
cmd.Parameters.Add(new SqlParameter("#RETURN_VALUE", System.Data.SqlDbType.Int, 0, System.Data.ParameterDirection.ReturnValue, false, 0, 0, "RETURN_VALUE", System.Data.DataRowVersion.Current, SqlInt32.Null));
cmd.Parameters.Add(new SqlParameter("#LoginId", SqlDbType.BigInt, 8, ParameterDirection.Input, false, 0, 0, "LoginId", DataRowVersion.Current, SqlInt64.Null));
cmd.Parameters.Add(new SqlParameter("#LoginName", SqlDbType.VarChar, 50, ParameterDirection.InputOutput,false, 0, 0, "LoginName", DataRowVersion.Current, SqlString.Null));
return cmd;
}
}
public class AuthenticationDBContext : DatabaseContextBase
{
public AuthenticationDBContext() : base()
{
}
public void GetLoginName(SqlInt64 LoginId, ref SqlString LoginName)
{
SqlCommand cmd = AuthenticationDBCommands.GetLoginName();
cmd.Parameters[1].Value = LoginId;
cmd.Parameters[2].Value = LoginName;
base.ExecuteNonQuery(cmd);
base.ReturnValue = (SqlInt32) cmd.Parameters[0].Value;
LoginName = (SqlString)(cmd.Parameters[2].Value);
}
}
So when it's used inside the ASP.NET web client it look like this:
protected string GetLoginName(long loginId)
{
SqlString loginName = SqlString.Null;
using (AuthenticationDBContext dbc = new AuthenticationDBContext())
{
dbc.GetLoginName(loginId, ref loginName);
}
return loginName.Value;
}
As you can see this is fairly standard stuff. But when the AuthenticationDBContext.GetLoginName() method is called by many different users in quick succession the loginName object is sometimes null.
When the SqlCommand.ExecuteNonQuery() fails to return any data it does not throw an exception.
I have tested the SQL and it always finds a value (I've inserted #LoginName into a table and it's never null). So the problem is happening after or in SqlCommand.ExecuteNonQuery();
As I said, this is an example of what it happening. In reality, data is not being returned for lots of different stored procedures.
It's also worth stating that other web clients that share the app pool in IIS are not affected when the web client in question is under a heavy load.
I'm using .NET 4.5 and my database is on SQL Server 2008.
Has anyone seen anything like this before?
Can anyone recommend any changes?
Thanks in advance,
Matt
UPDATE. Thanks for all your comments. I have made the following change to the DatabaseContextBase class.
private void ExecuteNonQueryImpl(SqlCommand command)
{
object _lockObject = new object();
lock (_lockObject)
{
SqlConnection con = this.GetConnection();
if (con.State != ConnectionState.Open)
{
con.Open();
}
// don't need a try catch as this is only ever called from another method in this
// class which will wrap it.
command.Connection = con;
command.Transaction = _transaction;
command.CommandTimeout = _commandTimeout;
for (int currentAttempt = 1; currentAttempt <= _maxDatabaseExecuteAttempts; currentAttempt++)
{
try
{
// do it
command.ExecuteNonQuery();
// done, exit loop
break;
}
catch (SqlException sex)
{
HandleDatabaseExceptions(currentAttempt, sex, command.CommandText);
}
}
if (!this.IsInTransaction)
{
con.Close();
}
}
}
public SqlConnection GetConnection()
{
if (this.IsInTransaction)
{
return this.Connection;
}
else
{
// check whether we've got a connection string (from either identity or static initialise)
if ( _connectionString == null )
{
string exceptionMessage = Language.Translate("DbContextNotInitialized");
throw new ArgumentNullException( "connectionString", exceptionMessage );
}
return new SqlConnection(_connectionString);
}
}
However, in a load test the data still sometimes comes back as null. The web client is not working in a transaction so a new SqlConnection object is created, opened and closed every time a call is made. (there are other areas of code which share the DatabaseContextBase class that do work in a transaction so the original connection property is needed)
I would like to mention that again that I'm confident that the store procedure is working correctly as I have inserted the #LoginName value into a table and it's never null.
Thanks,
Matt

Your "for loop" definition is not correct.
for (int currentAttempt = 1; currentAttempt == _maxDatabaseExecuteAttempts; currentAttempt++)
This will initialize currentAttempt to 1, run the loop, increment currentAttempt, and then check to see if currentAttempt is equal to 3, which it isn't, and exit the loop. I think what you want is
for (int currentAttempt = 1; currentAttempt <= _maxDatabaseExecuteAttempts; currentAttempt++)

How to fix a boolean method that returns true everytime asp.net

I designed my webpage to read a data string then display the results on labels in an html table. I am attempting to highlight the row that my database reads as a current order. My only problem is only one record is set to be active but they all highlight as if they were active. I use an array to set my data and I also use the label to get the ID I need (all is in code below). I have posted my method and where I use it in the asp page load. How can I fix my method to return correctly?
The implementing of the method in page load
if (lineData.IsCurrentOrderFind(L68.Text))
{
myTable.Rows[1].Cells[0].BgColor = "#FE2E2E";
myTable.Rows[1].Cells[1].BgColor = "#FE2E2E";
myTable.Rows[1].Cells[2].BgColor = "#FE2E2E";
myTable.Rows[1].Cells[3].BgColor = "#FE2E2E";
myTable.Rows[1].Cells[4].BgColor = "#FE2E2E";
}
Here is method that label above gets passed to
public bool IsCurrentOrderFind(string itemNumber)
{
StringBuilder sqlString = new StringBuilder();
sqlString.Append("SELECT * ");
sqlString.Append("FROM WorkOrder ");
sqlString.Append("WHERE LineNumber = " + ConfigurationManager.AppSettings["Line"] + " AND LineCompleted = 0 AND (ScaleGroup LIKE '%1' OR ScaleGroup LIKE '%3') ");
sqlString.Append(" AND CaseGenNum6 = #CaseGenNum6");
SqlDataReader reader = null;
SqlConnection dbConn = App_Code.DBHelper.getConnection();
SqlParameter[] parameters = new SqlParameter[] { new SqlParameter("#CaseGenNum6", itemNumber) };
try
{
reader = App_Code.DBHelper.executeQuery(dbConn, sqlString.ToString(), parameters);
while (reader.Read())
{
IsCurrentOrder = (reader["IsCurrentOrder"] != DBNull.Value && !string.IsNullOrEmpty(reader["IsCurrentOrder"].ToString())) ? true : false;
}
reader.Close();
reader.Dispose();
dbConn.Close();
dbConn.Dispose();
}
catch (Exception ex)
{
throw ex;
}
finally
{
if (dbConn != null)
{
try { dbConn.Close(); dbConn.Dispose(); }
catch { }
}
if (reader != null)
{
try { reader.Close(); reader.Dispose(); }
catch { }
}
}
if (IsCurrentOrder == true) I realize this is not necessary
{
return true;
}
else
{
return false;
}
}

The problem could be with this expression:
!string.IsNullOrEmpty(reader["IsCurrentOrder"].ToString())
Instead of calling ToString(), try simply casting it to a string:
!string.IsNullOrEmpty((string)reader["IsCurrentOrder"])
Possibly even better (the previous line might throw an exception if it's not really a string):
!string.IsNullOrEmpty(reader["IsCurrentOrder"] as string)
The reason being is that if the string is really null, calling ToString() will return a non-null string "null".

IsCurrentOrder is not declared locally. It seems to be declared at a higher scope. When you enter this function, nothing is initializing the variable (back to false). So, it is remaining at its last setting. Try this code instead:
public bool IsCurrentOrderFind(string itemNumber)
{
bool IsCurrentOrder = false;
//and the rest of your source code

the line
IsCurrentOrder = (reader["IsCurrentOrder"] != DBNull.Value && !string.IsNullOrEmpty(reader["IsCurrentOrder"].ToString())) ? true : false;
}
It's not actually checking the value of the field, only that it's not null or empty.
Try
if(
(reader["IsCurrentOrder"] != DBNull.Value
&&
!string.IsNullOrEmpty(reader["IsCurrentOrder"].ToString()))
)
{
IsCurrentOrder = reader["IsCurrentOrder"];
}
else
IsCurrentOrder = false;
I think there is a lot of refactoring you could do to this method though that will simplify the logic.

How to do pagination in couchdb using loveseat in c#

I need to do page load on scroll down in my application. I am using couchdb as my back end and I found a pagination option in couchdb which I think would satisfy my issue.
The thing is I can't find any working examples for pagination anywhere. I need someone's help in making my application work with this one.
Take a look at this for reference: https://github.com/soitgoes/LoveSeat/blob/master/LoveSeat/PagingHelper.cs
This is my code. I am getting an error in the options = model.GetOptions(); line, saying "object reference not set to an instance of an object".
public List<newVO> Getdocs(IPageableModel model)
{
List<newVO> resultList = new List<newVO>();
var etag = "";
ViewOptions options = new ViewOptions();
options = model.GetOptions();
options.StartKeyDocId = lastId;
options.Limit = 13;
options.Skip = 1;
var result = oCouchDB.View<newVO>("GetAlldocs", options);
//model.UpdatePaging(options, result);
if (result.StatusCode == HttpStatusCode.NotModified)
{
response.StatusCode = "0";
return null;
}
if (result != null)
{
foreach (newVO newvo in result.Items)
{
resultList.Add(newvo );
}
}
return resultList;
}
Thanks in advance. All ideas are welcome.
public List<newVO> Getdocs(IPageableModel model)
{
List<newVO> resultList = new List<newVO>();
var etag = "";
ViewOptions options = new ViewOptions();
options = model.GetOptions();
options.StartKeyDocId = lastId;
options.Limit = 13;
options.Skip = 1;
var result = oCouchDB.View<newVO>("GetAlldocs", options);
//model.UpdatePaging(options, result);
if (result.StatusCode == HttpStatusCode.NotModified)
{
response.StatusCode = "0";
return null;
}
if (result != null)
{
foreach (newVO newvo in result.Items)
{
resultList.Add(newvo );
}
}
return resultList;
}
This is my code and i am getting error in "options = model.GetOptions();" line that object reference not set to an instance of an object...

I've not used the LoveSeat paging implementation, but you can use the Limit and Skip properties on the ViewOptions to achieve paging:
public static IEnumerable<T> GetPage(this ICouchDatabase couchDatabase,
string viewName,
string designDoc,
int page,
int pageSize)
{
return couchDatabase.View(viewName, new ViewOptions
{
Skip = page * pageSize,
Limit = pageSize
}, designDoc);
}
This simple extension method will get a page of data from a CouchDB view

Get Identity Value from Typed DataSet

I got a typed dataset in my form. Using BindingSource to walk in rows, inserting and updating records.
Everything is fine but I need inserted records identity value for generating a string for my GeneratedCode field in my table.
After getting this value I'll send value to my CodeGen() method and generate string, and update same row's CodeGen field with this value.
I'm using Access database. I know there is that ##Identity thing for Access, but how can I use it? I don't want to use OleDbCommand or something like this.
How can I do that?
string GenCode(int pCariId)
{
string myvalue;
int totalDigit = 7;
myvalue = "CR" + pCariId.ToString();
for (int digit = myvalue.Length; digit <= totalDigit - 1; digit++)
{
myvalue = myvalue.Insert(2, "0");
}
return myvalue;
}
private void dataNavigator_ButtonClick(object sender, NavigatorButtonClickEventArgs e)
{
switch (e.Button.ButtonType)
{
case NavigatorButtonType.EndEdit:
try
{
this.Validate();
if (KaydetFlags == 1)
{
this.bndCariKayit.EndEdit();
datagate_muhasebeDataSet.TB_CARI.Rows[datagate_muhasebeDataSet.Tables["TB_CARI"].Rows.Count - 1]["INS_USR"] = 0;
datagate_muhasebeDataSet.TB_CARI.Rows[datagate_muhasebeDataSet.Tables["TB_CARI"].Rows.Count - 1]["INS_TRH"] = DateTime.Now;
XtraMessageBox.Show("Yeni Cari Kaydı Tamamlandı.");
KaydetFlags = 0;
}
else
{
DataRowView currentRow = (DataRowView)bndCariKayit.Current;
currentRow.Row["UPD_USR"] = "0";
currentRow.Row["UPD_TRH"] = DateTime.Now;
XtraMessageBox.Show("Cari Kaydı Güncellendi.");
this.bndCariKayit.EndEdit();
}
this.tB_CARITableAdapter.Update(datagate_muhasebeDataSet.TB_CARI);
}
catch (System.Exception ex)
{
XtraMessageBox.Show("Kayıt İşlemi Başarısız. Lütfen Tekrar Deneyiniz.");
}
break;

According to documentation you have to use RowUpdated method of your TableAdapter
private static void OnRowUpdated(
object sender, OleDbRowUpdatedEventArgs e)
{
// Conditionally execute this code block on inserts only.
if (e.StatementType == StatementType.Insert)
{
OleDbCommand cmdNewID = new OleDbCommand("SELECT ##IDENTITY",
connection);
// Retrieve the Autonumber and store it in the CategoryID column.
e.Row["CategoryID"] = (int)cmdNewID.ExecuteScalar();
e.Status = UpdateStatus.SkipCurrentRow;
}
}
Another option, which I actually use is to create Select query which simply gets maximum value from you id column:
SelectLastAddedId:
SELECT MAX(id) FROM obmiar
Just set query execute mode to scalar and you can refer to it in your code as
int lastId = TableAdapter.SelectLastAddedId()