Button animations and interactivity

[tomasherceg]

We have heard some complaints about the following scenario: "I need to run an animation on a button while a postback is running".

There are a several ways how to do this in DotVVM:

• create a custom postback handler and applying it to the control (universal and preferred way)
• attaching to beforePostback and afterPostback events using javascript (it can disable all buttons globally, or only the button which fired the postback, when used e.g. from a custom knockout binding)

To simplify the syntax, there are also several options:

• ihnerit from the default Button control and create e.g. the AnimatedButton control
• create a Decorator
• create an active property (which can add a custom behavior to an existing control)
• using server-side styles (which are not documented yet)

However, I agree that neither of the methods is simple.

I can imagine several solutions:

• create a control in the DotVVM Contrib
• prepare a generic postback handler that can run a script before or after the postback
• prepare an active property which can apply a CSS class while a postback is running on the specific control (e.g. PostBack.IsBusyCssClass="processing")

[djanosik]

We should prefer simple solution that will not require users to write their own JavaScript. I think it's good enough to prepare some decorator or active property.

[exyi]

I think that we should have

• <dot:PostbackIsRunning CssClass='' - A postback handler that will attach a css to the control when the postback is running.
• The PostBack.IsBusyCssClass="processing" - an active property that will attach the postback handler
• _page.PostbackRunning a property that can be used in binding anywhere. We could also have _queue.PostbackRunningQueue [ == "MyPostbackGroup"] that would return a queue of the running postback.

@tomasherceg What do you think?

[tomasherceg]

We should have a discussion about the right solution - I like PostBack.IsBusyCssClass for simple scenarios and full postback handler for all other scenarios.