Why the string parameter in Excute method is an out parameter

[KM_Yotsuha]

Revit API document on Excute method of IExternalCommand interface:

parameter string is an out parameter,why is that? it should be a ref parameter.

[caroline.gitonga · Accepted solution]

Hi @KM_Yotsuha,

This might probably be a slight documentation mistake. The 'message' string parameter on the 'execute' method should be 'ref'. Refer to SDK samples. While the implementations of the two keywords but be slightly close, thank you for noting this and I will reach out to the tech team about it.

[mhannonQ65N2]

It is an out parameter because it is returned from the Execute method. Making it a ref parameter would imply that it is providing information to the Execute method. Why do you think it should be a ref parameter?

[KM_Yotsuha]

because code in visual studio is ref: