/// <summary>Saves changes made to the data source.</summary>
/// <returns>Number of records affected by the Save operation; -1 if an
/// error occurred.</returns>
/// <remarks>This method will automatically attempt a graceful closure of the handle to the underlying data source in the case that the return value is -1. If the underlying unit of work has not been initialized, or the database is offline, this method also returns -1.</remarks>
public int Save()
{
if (!EmployeesConnectionTester.IsDatabaseOnline())
{
return(-1);
}
if (UnitOfWork == null)
{
return(-1); // unit of work not initialized
}
var result = -1;
try
{
result = UnitOfWork.Save();
// Notify event subscribers that changes have been saved successfully.
OnChangesSaved(result);
}
catch (Exception ex)
{
OnExceptionRaised(ex);
result = -1;
}
return(result);
}
/// <summary>
/// Sets up the data context and initializes the database connection. Checks
/// whether the underlying database is available.
/// </summary>
/// <param name="connectionString">String containing the connection string
/// to use to access the data source. Must not be blank.</param>
/// <returns>True if succeeded; false otherwise.</returns>
/// <remarks>
/// This method should be called prior to any actual database operations
/// for each unit of work. The reasoning being that this method also ensures
/// the connection to the underlying database is intact prior to actually
/// allowing the context to be utilized.
/// </remarks>
protected virtual bool OnCreateContext(string connectionString)
{
if (string.IsNullOrWhiteSpace(connectionString))
{
return(false);
}
if (!EmployeesConnectionTester
.IsDatabaseOnline())
{
OnDatabaseNotAvailable();
return(false);
}
// Check if already connected
if (Context != null)
{
return(true);
}
var result = true;
try
{
Context = new EmployeesEntities(connectionString);
}
catch (Exception ex)
{
OnExceptionRaised(ex);
result = false;
}
finally
{
if (!result)
{
GracefullyCloseDatabase();
}
}
if (result)
{
OnDatabaseConnected();
}
return(result);
}