CTrack inherits from C4DAtom which has the write() and read() member functions. So you should be able to write them directly to your hf.

See the docs: BaseDocument.GetMode()

edited my answer accordingly. Messed up the order. ;)

On InitValues(), you're resetting the list. Since InitValues() is usually called once one construction(if done right) and CreateLayout() everytime, the Dialog is opened your list is reset.

I modified your code to dynamically react to IDs. (Btw, it's now a script for simple demonstration).
edit: Actually, this is just shifting the problem. There's no way in python I know of to bind functions directly. (Wouldn't make sense on dynamically added Gadgets anyways, imho.)

import c4d
from c4d import gui
PLUGIN_ID = 1450011099

# Based from Pim Grooff's code 
# https://www.youtube.com/watch?v=jlQ2JBJvX5s

def print_me(id):
    print id

class MyDialog(gui.GeDialog):

    def InitValues(self):
        self.newfieldindex = 0

        return True

    def CreateLayout(self):
        self.SetTitle("Add/Remove Enable/Disable Dialog")

        self.GroupBegin(id=1002, flags=c4d.BFH_MASK, cols=2)
        self.AddButton(1021, c4d.BFV_MASK, initw=145, name="Add")
        self.AddButton(1022, c4d.BFV_MASK, initw=145, name="Remove")
        self.GroupEnd()


        self.GroupBegin(id=1030, flags=c4d.BFH_MASK, cols=1)
        self.GroupEnd()

        return True

    def Command (self, id ,msg):
        if (id==1021):
            self.LayoutFlushGroup(id=1030)
            self.newfieldindex += 1
            if (self.newfieldindex < 0):
                self.newfieldindex = 0

            for newid in range(1,self.newfieldindex+1):
                button_id = newid + 1030
                fieldname = "Add-" + str(newid)

                self.AddButton(button_id, c4d.BFV_MASK, initw=145, name=fieldname)

            self.LayoutChanged(id=1030)
            return True


        elif (id==1022):
            self.LayoutFlushGroup(id=1030)
            self.newfieldindex -= 1
            if (self.newfieldindex < 0):
                self.newfieldindex = 0

            for newid in range(1,self.newfieldindex+1):
                button_id = newid + 1030
                fieldname = "Add-" + str(newid)

                self.AddButton(button_id, c4d.BFV_MASK, initw=145, name=fieldname)

            self.LayoutChanged(id=1030)
            return True

        else:
            print_me(id)
        return True




if __name__ == "__main__":
    dlg = MyDialog()
    dlg.Open(dlgtype=c4d.DLG_TYPE_ASYNC, pluginid=PLUGIN_ID)

Since it is a BaseContainer you simply remove them via RemoveData()

Yes, when Layout is flushed, it is flushed. :)
You have to add your controls again, between LayoutFlushGroup() and LayoutChanged(). This is the most common way to build dynamic layouts.

Create a helper function to create your layout. Then, you can call it when needed (CreateLayout(), MyUpdateRoutine() and so on.)

No, not that I know of.
But you can indeed create adapter functions for queries that convert query strings to their corresponding Int equivalent.
I wouldn't recommend it though, because this adds another level of abstraction.

Have you tried running it without any plugins?

@BigRoy said in Custom menu in C4D top menu bar with custom Python commands:

Bug with C4D and PYTHONPATH
I did hit a C4D bug as I started setting up the pipeline integration, whenever there's an empty value in the list on PYTHONPATH then Python fails to run correctly in Cinema4D. More details here

Nice find. This is a bug or maybe a limitation. :)

I've tried to add an icon to the menu but I failed there. I tried to pass it a .svg icon like so:

Yea, that won't work. SVG is not supported. Use TIFF instead (others are possible).

However, it kept failing with:
Traceback (most recent call last):

File "C:\Users\Roy\AppData\Roaming\Maxon\Maxon Cinema 4D R21_64C2B3BD\library\scripts\untitled.py", line 16, in <module>

doc = c4d.documents.LoadFile(path)

TypeError:unable to convert unicode to @net.maxon.interface.url-C

This is most likely because you didn't decode it as UTF-8 when giving it to a python-function. (Assuming you used LoadDialog or similar c4d-specific function).
Python uses unicode, Cinema 4D's default coding is utf8.