program selection

[user125]

Is there a function that host calls when user changes program in the drop down list of plugin window?

[Keith99]

there is

virtual void setProgram (VstInt32 program) { curProgram = program; }

which you can override

[user125]

Actually, I checked setProgram() at first, and it wasn't called by the host when the event happened. Code within the function wasn't executed, and I also hit a breakpoint inside the function, but debugger didn't get to the breakpoint, when the event occured.

[Keith99]

Hmm that is odd. you could try just trapping the message

[Big Tick]

It only works if you select a program from the host. If you select a program from the plugin window, the host will not call anything (however, the plugin should call updateDisplay() to notify the host that the current program has changed)

[user125]

Where is the item selection event actually handled? We don't create the control that contains the list of programs; it's created automatically by the host. Shouldn’t setPorgram() be called somewhere, when the program is selected from the list?

[Big Tick]

if the list is part of the host UI, then yes, selecting an item in the list should call setProgram()
Just double-check your method signature. It should be:

Code: Select all

virtual void setProgram (VstInt32 program);

[user125]

if the list is part of the host UI, then yes, selecting an item in the list should call setProgram()
Just double-check your method signature. It should be:

Code: Select all

virtual void setProgram (VstInt32 program);

Programs list, on the top of plugin window.

[user125]

Ok, the problem is solved. My function was declared like this:

Code: Select all

virtual void setProgram (long program);

and after changing the parameter to VstInt32, setProgram() is called by the host after selection.

[Big Tick]

A classic c++ bug....

In order to avoid it, make sure you use the c++11 override keyword. If you had declared your function like this:

Code: Select all

virtual void setProgram (long program) override;

the compiler would have complained immediately, saving you hours of debugging time.

[Miles1981]

+1 for override. And turn these warnings to errors even!