Hi partner,
If you want to set multi select option to other record, you could use the following code.
Get multi select option value
Entity entity = _service.Retrieve("account", new Guid(old RecordId), new ColumnSet("new_multioption"));
Entity accountEntity = new Entity ("account", new Guid(New RecordId));
accountEntity["new_multioption"] = entity.GetAttributeValue("new_multioption");
Set multi select option value (single value)
OptionSetValueCollection collectionOptionSetValues = new OptionSetValueCollection();
OptionSetValue optionSet = new OptionSetValue(optionsetValue);
collectionOptionSetValues.Add(optionSet);
entityAccount["new_multioption"] = collectionOptionSetValues;
_service.Update(entityAccount);
Set multi select option value (multi value)
string[] arr = { collection of option set value };
foreach(var item in arr)
{
collectionOptionSetValues.Add(new OptionSetValue(Convert.ToInt32(item)));
}
entityAccount["new_multioption"] = collectionOptionSetValues;
_service.Update(entityAccount);
You could also refer to the following links.
https://www.inogic.com/blog/2018/09/multi-select-option-set-field-in-dynamics-365-v9-0/
https://itsfascinating.com/d365/tag/multiselect-option-set/
https://www.encorebusiness.com/blog/multi-select-option-sets-in-dynamics-365-customer-engagement/
Best Regards,
Leo
