/// <summary>
/// Save audit entities where the value of some properties were unknown at previous step.
/// <br/><br/>
/// https://www.meziantou.net/entity-framework-core-history-audit-table.htm
/// </summary>
/// <method>OnAfterSaveChangesAsync(List<AuditEntry> auditEntries)</method>
private Task OnAfterSaveChangesAsync(List <AuditEntry> auditEntries)
{
if (auditEntries == null || auditEntries.Count == 0)
{
return(Task.CompletedTask);
}
foreach (var auditEntry in auditEntries)
{
// Get the final value of the temporary properties
foreach (var prop in auditEntry.TemporaryProperties)
{
if (prop.Metadata.IsPrimaryKey())
{
auditEntry.KeyValues[prop.Metadata.Name] = prop.CurrentValue;
}
else
{
auditEntry.CurrentValues[prop.Metadata.Name] = prop.CurrentValue;
}
}
// Save the Audit entry
AuditHistory.Add(auditEntry.ToAuditHistory());
}
return(SaveChangesAsync());
}
/// <summary>
/// Audit History record to write
/// </summary>
/// <method>ToAuditHistory()</method>
public AuditHistory ToAuditHistory()
{
string file = this.GetType().Assembly.Location;
string app = System.IO.Path.GetFileNameWithoutExtension(file);
var auditHistory = new AuditHistory();
auditHistory.Entity = TableName;
auditHistory.State = State;
auditHistory.Application = app;
auditHistory.ModifiedBy = ModifiedBy;
auditHistory.ModifiedOn = ModifiedOn;
auditHistory.KeyValues = JsonConvert.SerializeObject(KeyValues);
auditHistory.OriginalValues = OriginalValues.Count == 0 ? null : JsonConvert.SerializeObject(OriginalValues);
auditHistory.CurrentValues = CurrentValues.Count == 0 ? null : JsonConvert.SerializeObject(CurrentValues);
return(auditHistory);
}
/// <summary>
/// Save audit entities that have all the modifications and return list of entries
/// where the value of some properties are unknown at this step.
/// <br/><br/>
/// https://www.meziantou.net/entity-framework-core-history-audit-table.htm
/// </summary>
/// <returns>List<AuditEntry></returns>
/// <method>OnBeforeSaveChanges(string userId)</method>
private List <AuditEntry> OnBeforeSaveChanges(string userId)
{
ChangeTracker.DetectChanges();
var auditEntries = new List <AuditEntry>();
foreach (var entry in ChangeTracker.Entries())
{
if (entry.Entity is AuditHistory || entry.State == EntityState.Detached || entry.State == EntityState.Unchanged)
{
continue;
}
var auditEntry = new AuditEntry(entry);
auditEntry.TableName = entry.Metadata.GetTableName();
auditEntry.ModifiedBy = userId;
auditEntry.ModifiedOn = DateTime.UtcNow;
auditEntry.State = entry.State.ToString();
auditEntries.Add(auditEntry);
foreach (var property in entry.Properties)
{
if (property.IsTemporary)
{
// value will be generated by the database, get the value after saving
auditEntry.TemporaryProperties.Add(property);
continue;
}
string propertyName = property.Metadata.Name;
if (property.Metadata.IsPrimaryKey())
{
auditEntry.KeyValues[propertyName] = property.CurrentValue;
continue;
}
switch (entry.State)
{
case EntityState.Added:
auditEntry.CurrentValues[propertyName] = property.CurrentValue;
break;
case EntityState.Deleted:
auditEntry.OriginalValues[propertyName] = property.OriginalValue;
break;
case EntityState.Modified:
if (property.IsModified)
{
auditEntry.OriginalValues[propertyName] = property.OriginalValue;
auditEntry.CurrentValues[propertyName] = property.CurrentValue;
}
break;
}
}
}
// Save audit entities that have all the modifications
foreach (var auditEntry in auditEntries.Where(_ => !_.HasTemporaryProperties))
{
AuditHistory.Add(auditEntry.ToAuditHistory());
}
// keep a list of entries where the value of some properties are unknown at this step
return(auditEntries.Where(_ => _.HasTemporaryProperties).ToList());
}