// Use OnBeforeSaveChanges if all the values are known before actually saving the row -> saved at the same time as other entries
private List <DataLogEntry> OnBeforeSaveChanges()
{
ChangeTracker.DetectChanges();
var dataLogEntries = new List <DataLogEntry>();
foreach (var entry in ChangeTracker.Entries())
{
if (entry.Entity is DataLog || entry.State == EntityState.Detached || entry.State == EntityState.Unchanged)
{
continue;
}
var dataLogEntry = new DataLogEntry(entry)
{
TableName = entry.Metadata.Name,
ActionType = entry.State.ToString()
};
dataLogEntries.Add(dataLogEntry);
foreach (var property in entry.Properties)
{
if (property.IsTemporary)
{
// value will be generated by the database, get the value after saving
dataLogEntry.TemporaryProperties.Add(property);
continue;
}
string propertyName = property.Metadata.Name;
if (property.Metadata.IsPrimaryKey())
{
dataLogEntry.KeyValues[propertyName] = property.CurrentValue;
continue;
}
switch (entry.State)
{
case EntityState.Added:
dataLogEntry.NewValues[propertyName] = property.CurrentValue;
break;
case EntityState.Deleted:
dataLogEntry.OldValues[propertyName] = property.OriginalValue;
break;
case EntityState.Modified:
if (property.IsModified)
{
dataLogEntry.OldValues[propertyName] = property.OriginalValue;
dataLogEntry.NewValues[propertyName] = property.CurrentValue;
}
break;
}
}
}
// Save dataLog entities that have all the modifications
foreach (var dataLogEntry in dataLogEntries.Where(_ => !_.HasTemporaryProperties))
{
DataLogs.Add(dataLogEntry.ToDataLog());
}
// keep a list of entries where the value of some properties are unknown at this step
return(dataLogEntries.Where(_ => _.HasTemporaryProperties).ToList());
}
