NullReferenceException occurs in the ModuleUpdater.CreateCommand method in ASP.NET applications

Hello Martin,

UPDATED:
Starting with version 17.2.5, we improved our code to make ModelUpdater methods work correctly when data store pooling is specified in the connection string. Refer to the T587235 ticket for details.
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Thank you for your feedback. Currently, updating the database through the ExecuteScalarCommand method is not supported for applications that use the connections pool. We will consider improving this in the future. However, since currently, the Updater class is XPO-independent, this will require significant changes, while your ticket is the first one where this functionality was requested. You can use the following code to get the correct IDbConnection instance in the current version:

C#
using DevExpress.Xpo.DB;  
using DevExpress.Xpo.Helpers;  

namespace MainDemo.Module.DatabaseUpdate {  
    public class Updater : ModuleUpdater {  
        public Updater(IObjectSpace objectSpace, Version currentDBVersion) : base(objectSpace, currentDBVersion) { }  

        private ConnectionProviderSql updatingProvider;  
        public override void UpdateDatabaseBeforeUpdateSchema() {  
            base.UpdateDatabaseBeforeUpdateSchema();  
            DataStorePool pool = ((BaseDataLayer)(((XPObjectSpace)ObjectSpace).Session).DataLayer).ConnectionProvider as DataStorePool;  
            if (pool != null) {  
                updatingProvider = (ConnectionProviderSql)pool.AcquireUpdateSchemaProvider();  
            }  
            try {  
                // place your updating code here  
                RenameColumn("Payment", "Hours", "Hours1");  
            } finally {  
                if (pool != null && updatingProvider != null) {  
                    pool.ReleaseUpdateSchemaProvider(updatingProvider);  
                    updatingProvider = null;  
                }  
            }  
        }  
        protected override System.Data.IDbCommand CreateCommand(string commandText) {  
            if (updatingProvider != null) {  
                IDbCommand command = updatingProvider.Connection.CreateCommand();  
                command.CommandText = commandText;  
                return command;  
            } else {  
                return base.CreateCommand(commandText);  
            }  
        }  
        ...  
    }  
}  

Please let me know if you find any issue with it.