clojure-clr how to wire up a delegate

[adam11235]

Hi,

I've made progress in creating a simple app to show a windows form,
however I am having trouble wiring up a delegate (to handle button
clicks).

The Java version uses Proxy to implement ActionListener, instead I am
just trying to create an EventHandler passing as the 2nd constructor
argument the code I would like executed. (see the .add_Click line)

The delegate code gets invoked immediately instead of when the button
click occurs, and then complains it expected a function pointer rather
than the DialogResult it received (due to execution of the code)

I tried quoting that code but no success.

How do you wire up delegates?

(import '(System.Windows.Forms MessageBox Form Button))

(defn windowsPlay []
(let
[ win (Form.)
temp-button (Button.)
]
(.. win (get_Controls) (Add temp-button))
(doto temp-button
(.set_Top 50)
(.set_Text "Clicky")
(.add_Click (EventHandler. temp-button (MessageBox/Show "I got
clicked"))))
(doto win
(.set_Text "hello")
(.ShowDialog))))

(windowsPlay)

Thanks, Adam.

[Joop Kiefte]

Tried to encapsulate what you want to put in the eventhandler in an
anonymous function?

And I don't know how that works in Clojure-CLR, but you might need proxy...

2010/2/24 adam11235 <adam.k...@gmail.com>:

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[Joop Kiefte]

Forget about the proxy part, re-read your message... =x

2010/2/24 Joop Kiefte <iko...@gmail.com>:

[soyrochus]

Hi Adam,

You need to use the gen-delegate macro to create delegates,

See http://wiki.github.com/richhickey/clojure-clr/clr-interop

The signature of the macro is (gen-delegate Type [args] body) whereby
in case of event-handlers you would typically use the EventHandler
class.
The code becomes then:

(System.Reflection.Assembly/LoadWithPartialName
"System.Windows.Forms")

(import '(System.Windows.Forms MessageBox Form Button))

(defn windowsPlay []
(let [win (Form.)
temp-button (Button.)]
(.. win (get_Controls) (Add temp-button))
(doto temp-button
(.set_Top 50)
(.set_Text "Clicky")

(.add_Click (gen-delegate EventHandler [sender args] (MessageBox/

Show "I got clicked"))))
(doto win
(.set_Text "hello")
(.ShowDialog))))

(windowsPlay)

Regards,

Iwan

[adam11235]

Excellent that worked.

For other clojure-clr newbies, the Clojure.Source project has some
samples that are helpful.

Thanks, Adam.

On Feb 25, 7:39 am, soyrochus <iwanvanderkle...@gmail.com> wrote:
> Hi Adam,
>
> You need to use the gen-delegate macro to create delegates,
>

> Seehttp://wiki.github.com/richhickey/clojure-clr/clr-interop

[dmiller]

Parallel to proxy, clojure-clr adds a gen-delegate. Example code is
in

http://github.com/richhickey/clojure-clr/blob/master/Clojure/Clojure.Source/clojure/samples/celsius.clj

Specifically, for adding an EventHandler:

(.add_Click button
(gen-delegate EventHandler [sender args]
(let [c (Double/Parse (.Text tb)) ]
(.set_Text f-label (str (+ 32 (* 1.8 c)) " Fahrenheit")))))

-David