How to stop opening multiple instances of addin

[Anonymous]

Is there a way to stop opening multiple instances of add-in. In my revit add-in, the user can open multiple instances of the application by clicking the addin button again and again. I would like to know, how do I stop the user to click addon button for multiple times?

Appreciate any help.

Thank you.

[jeremytammik · Accepted solution]

That is not normal.

You are probably displaying a modeless form each time you run your external command.

Display a modal form instead, and life will be easier and safer.

I.e., use ShowDialog instead of Show.

Cheers,

Jeremy

[Anonymous]

I changed Show method to ShowDialog and it worked. Thanks again @jeremytammik your constant support for revit-api community is admirable. Stay blessed.

- Ali

[Anonymous]

Hi dear @jeremytammik ,

what if I need to work with modeless forms or want to create dockable panels

how can we prevent new windows from showing up while the first window is running

many thanks in advance

[RPTHOMAS108]

Store a static variable, upon form loaded set it to true, upon form close set it to false.

In-between: Before opening form check static variable. 

[Anonymous]

i did that but could not return it back to false to be able to run the form again

I found nice solution.

using registry to save the value and read write it from anywhere in the app

[jeremy_tammik]

Congratulations on solving your task! However, I would call saving to the registry a 'not-so-nice' solution, since it sounds like total overkill for what you really need.

[Kennan.Chen]

Making the window object a singleton solves your problem. Further more you can use the .NET Mutex class to achieve a system-level singleton