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POWhy my MysqlDataReader object becoming null?
 

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  1. POWhy my MysqlDataReader object becoming null?
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    <p>I have the following class:</p> <pre><code>using System; using System.Collections; using System.Collections.Generic; using System.Data; using System.Diagnostics; using MySql.Data.MySqlClient; namespace DataBaseModule.General { public class ManagedDataReader : IDisposable { private bool _disposed = false; private MySqlCommand _command; private MySqlDataReader _dataReader; // The class constructor. public ManagedDataReader(string StrSQL) : this(new MySqlCommand(StrSQL)) { } public ManagedDataReader(MySqlCommand SQL_Cmd) { try { _command = SQL_Cmd; _command.Connection = new MySqlConnection(DbAccessProvider._connectionString); DbAccessProvider.SqlCommandsPerformed++; _command.Connection.Open(); _dataReader = _command.ExecuteReader(); } catch (Exception ex) { DataBaseModule.Log.CommonLogger.Log_Database_Error(new Exception("Sql command Was: " + _command.CommandText, ex)); throw ex; } } public int VisibleFieldCount() { return _dataReader.VisibleFieldCount; } public bool Read() { return _dataReader.Read(); } public object this[int i] { get { if (_dataReader[i].Equals(DBNull.Value)) { return null; } else { return _dataReader[i]; } } } public object this[string FieldName] { get { if (_dataReader[FieldName].Equals(DBNull.Value)) { return null; } else { return _dataReader[FieldName]; } } } // Implement IDisposable. // Do not make this method virtual. // A derived class should not be able to override this method. public void Dispose() { Dispose(true); // This object will be cleaned up by the Dispose method. // Therefore, you should call GC.SupressFinalize to // take this object off the finalization queue // and prevent finalization code for this object // from executing a second time. GC.SuppressFinalize(this); } // Dispose(bool disposing) executes in two distinct scenarios. // If disposing equals true, the method has been called directly // or indirectly by a user's code. Managed and unmanaged resources // can be disposed. // If disposing equals false, the method has been called by the // runtime from inside the finalizer and you should not reference // other objects. Only unmanaged resources can be disposed. protected void Dispose(bool disposing) { // Check to see if Dispose has already been called. if (!this._disposed) { // If disposing equals true, dispose all managed // and unmanaged resources. if (disposing) { if (_dataReader != null) { _dataReader.Close(); } if (_command != null) { if (_command.Connection != null) { _command.Connection.Dispose(); _command.Connection = null; //Free the reference. } _command.Dispose(); } } // Call the appropriate methods to clean up // unmanaged resources here. // If disposing is false, // only the following code is executed. // Note disposing has been done. _disposed = true; } } // This finalizer will run only if the Dispose method // does not get called. // It gives your base class the opportunity to finalize. // Do not provide finalize methods in types derived from this class. ~ManagedDataReader() { // Do not re-create Dispose clean-up code here. // Calling Dispose(false) is optimal in terms of // readability and maintainability. Dispose(false); } } } </code></pre> <p>My problem is that for some reason, sometimes i got exception when calling Read(): the exception is that my _dataReader member is null.</p> <p>That's weird, because i have try-catch block on its initialization, and no exception is caught (i use my loging mechanism to check this).</p> <p>This behavior is rare, but occures aprox. once a week (i'm running milions of queries per day)</p> <p>Thanks a lot to anyone who tries to solve this mistery!!</p>
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    1. This table or related slice is empty.
    1. PTQuestion
    1. USsvick
    1. USEitan H.S.
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    1. This table or related slice is empty.
    1. This table or related slice is empty.
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    2. PO
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      1. POWhy my MysqlDataReader object becoming null?
      1. USSergey Brunov
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    2. VO
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      1. POWhy my MysqlDataReader object becoming null?
      1. USDamon Achey
      1. VTFavorite
    1. CODon't use `throw ex;`, it loses useful information from the exception. Use just `throw;` instead.
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    2. COAre you sure it's `_dataReader` that is `null` and not some other object?
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    3. COsvick - i'm sure.
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      1. USEitan H.S.
 

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