MSG_UPDATE is sent after pressing button in Material Data

[peterakos]

Hello.

When I press a button in MaterialData, the message MSG_DESCRIPTION_COMMAND is sent.
After that I always receive a MSG_UPDATE as well.
Is there anything I should do to avoid that ?

After handling the button callback, I return TRUE.

Thank you.

[m_adam]

Hi @peterakos, MSG_DESCRIPTION_COMMAND is used to trigger the action of pressing the button.
But in most of the case, if there is a button, it's to do something, so actually modify something which will then probably trigger a MSG_UPDATE.

Moreover you can test it with a Python Generator and UserData button attached. If you click on the button only MSG_DESCRIPTION_COMMAND is triggered.

import c4d

def message(id, data):
    if id == c4d.MSG_DESCRIPTION_COMMAND:
        print "Button Clicked"
    elif id == c4d.MSG_UPDATE:
        print "MSG_UPDATE"
        
    return True

def main():
    return c4d.BaseObject(c4d.Ocube)

May I ask you what are you trying to achieve?
Cheers,
Maxime.

[peterakos]

Hello.

Thank you very much for your clarification on this.
I have a button in MaterialData that saves the material in a specific format in the disk.
I doesn't change anything in the material but the MSG_UPDATE is sent anyway.
So, since I don't want to run the MSG_UPDATE handler, I have to set a flag to true in order to skip it.

Thank you.