In a requirement we were asked to show one specific field change history in a custom portal written in PHP, our imeediate action was to call RetrieveAttributeChangeHistory via WebApi but if was just returning the list of value history without any other fields but geting ChangedOn and ChangedBy field was our requirement. (see details in github issue here).
We finally headed to our good old CRM SDK libraries and written code in C# then access this via Dyanmics 365 WebApi using Dynamics 365 Custom Action.
I’m sharing here core logic, it can be used according to your own requirement, either in Action or any other place where CRM SDK C# libraries can be consumed.
Model class to get history as a list
public class FieldHistory
{
public string ChangedBy { get; set; }
public DateTime ChangedOn { get; set; }
public string Oldvalue { get; set; }
public string NewValue { get; set; }
}
Function to get and parse field history
Below code is using FormattedValues which retrieve user readable component out of OptionSet and EntityReference fields, this can be modifield according to your requirements.
public static List<FieldHistory> GetFieldHistory(string entityLogicalName, Guid recordId, string fieldName, IOrganizationService service)
{
var attributeChangeHistoryRequest = new RetrieveAttributeChangeHistoryRequest
{
Target = new EntityReference(entityLogicalName, recordId),
AttributeLogicalName = fieldName
};
var attributeChangeHistoryResponse = (RetrieveAttributeChangeHistoryResponse)service.Execute(attributeChangeHistoryRequest);
var details = attributeChangeHistoryResponse.AuditDetailCollection;
var fieldHistory = new List<FieldHistory>();
foreach (var detail in details.AuditDetails)
{
var detailType = detail.GetType();
if (detailType == typeof(AttributeAuditDetail))
{
// retrieve old & new value of each action of each audit change from AttributeAuditDetail
var attributeDetail = (AttributeAuditDetail)detail;
var userName = attributeDetail.AuditRecord.GetAttributeValue<EntityReference>("userid").Name;
var changedOn = attributeDetail.AuditRecord.GetAttributeValue<DateTime>("createdon");
var newValue = attributeDetail.NewValue.FormattedValues[fieldName];
var oldValue = attributeDetail.OldValue?.FormattedValues[fieldName];
fieldHistory.Add(new FieldHistory
{
ChangedBy = userName,
ChangedOn = changedOn,
Oldvalue = oldValue,
NewValue = newValue
});
return fieldHistory;
}
}
}
If you observe I have use safe navigation operator for var oldValue = attributeDetail.OldValue?.FormattedValues[fieldName]; this is because for the first occurrence OldValue will always remain null.
This code is good if we are using in C# specific requiremnt, while it’s a workaround if we need field history via WebAPI. Let’s keep an eye in official documentation and in this issue if Microsoft returns more meaningful response in future.
Hope this helps.
