Using Ironjs. I have a c# function registered as a JS function (via SetGlobal)
It gets called , but I want to return a value to from that function. The value is an IEnumerable of CLR objects. Using Jint this just works: I return the object and can foreach it etc, how do I do the same thing in IronJS (Why not use Jint, well it has bugs, for example it wont compile underscore.js)
EDIT: Since I am not a fluent F# person I cannot answer this question myself by reading the code. So instead I fixed Jint. However it would still be nice to know the answer
We are still working on our .NET interop. As such, the foreach in IronJS is not set up to enumerate IEnumerables, but instead works on CommonObject type objects.
Related
I need to execute an JavaScript function from my Visual C++ Code with the return value of the JavaScript function. In my Windows Visual C++ CLR project I have an Windows Form with an WebBrowser in it.
I tried:
Object^ result = webBrowser1->Document->InvokeScript("document.getElementById('communication').innerHTML;");
String^ resutlString = result->ToString();
Using this i get the Error 'System.NullReferenceException As far as I know this means smth like result equals null.
Actually not even this
webBrowser1->Document->InvokeScript("document.getElementById('communication').innerHTML = 'test';")
is doing anything.
Edit:
It seems I did't understand the method InvokeScript right you have to pass a JavaScript function name not just any JavaScript Code webBrowser1->Document->InvokeScript("jsFunction") is working but I'm still getting 'System.NullReferenceException when trying to Convert result to a string
Ok everything seems to work I had a typo in my JavaScript so the function never returned anything
So I am doing a simple personal project in winforms with F#. My code used to work, but now throws this exception for seemingly no reason.
An unhandled exception of type 'System.InvalidOperationException' occurred in FSharp.Core.dll
Additional information: The initialization of an object or value resulted in an object or value being accessed recursively before it was fully initialized.
The code is a member method that is being invoked from the constructor of the form itself
do
//lots of other constructor code before this point
// render the form
form.ResumeLayout(false)
form.PerformLayout()
form.ReloadGoals
//several other members before here
member form.ReloadGoals =
let x = 10 //crashes on this line
The website where I grabbed the template for the project I am using is this one.
Unfortunately I have made some substantial additions to this.
I would be glad to post more code, but I need to know what code would be relevant exactly, as I am not exactly sure and don't want to bog down the post in extraneous code.
Also I can't really find a lot of documentation on System.InvalidOperationException.
Every time I find it, it is being used as an example of an exception you can throw on your own, not what causes it.
See The F# 3.0 Language Specification (final version, PDF), ยง8.6.1 Primary Constructors in Classes:
During construction, no member on the type may be called before the last value or function definition in the type
has completed; such a call results in an InvalidOperationException.
Almost certainly, your code in the question doesn't tell the full story. If you hit the above
mentioned restriction, then there's somewhere an attempt to access a field or member not fully initialized.
Some example:
type X() as this =
let x = this.X
member __.X = 42
X()
One workaround might be to encapsulate the offending code in a member of its own and call that in the constructor instead. Another would be the wrapping in a function definition.
This will be an incomplete answer, since I cannot reproduce the problem (using F# interactive, the given example, the ReloadGoals modification, and Form.Show, the code runs fine). However, there are strange things happening:
Taken from the template, there should be a handler method for the Form.Load event, which fires when the type is fully constructed. Why is additional loading code in the constructor instead of this event handler? Load exists precisely to counter this kind of problem with unorderly initialization.
The template you are using isn't exactly sane F#. For example, initControls is a value of type unit that is evaluated where it is defined; its binding to a name is absolutely useless and should be replaced with a simple do. Writing initControls in the do block later has no effect at all. form.ResumeLayout(false); form.PerformLayout() should be equivalent to form.ResumeLayout(true), but I don't understand what these are doing in the constructor in the first place. The event handlers have two possibly unnecessary indirections: one to a delegate constructor, another to a method that has no real reason to exist -- the handlers should be lambdas or simple, private functions. Why are they public members?!
The error appearing in the question is probably caused by the usage of form in its own constructor. Move your new usage to the Load event handler, and it should work.
Personally, I would go further and ditch implementation inheritance by instantiating a plain Form and subscribing to its events. For example, in FSI, something similar to the template could be done like this:
open System.Drawing
open System.Windows.Forms
let form = new Form()
form.ClientSize <- new Size(600, 600)
form.Text <- "F# Form"
let formLabel = new Label()
formLabel.Text <- "Doubleclick test!"
formLabel.DoubleClick.Add <| fun _ -> form.Close()
form.Controls.Add(formLabel)
form.Show()
which uses no inheritance at all. (In an application, you'd use Application.Run etc instead of form.Show().) This does not run into initialization problems as easily and, additionally, is very useful if you want to encapsulate the form inside a simpler type or even just a function.
I have an array in my main
public var graphArray:Array = [1,2,3,4,5,6];
And I'm trying to access it from within a MovieClip that I've put on my timeline using:
var graph1scale:Number = MovieClip(root).graphArray[0]
It looks like it would make sense to me but when I try to run it I get this error:
TypeError: Error #1009: Cannot access a property or method of a null object reference.
Am I wrong to be using MovieClip(root) to try and access it? I've only just started using external classes (this is my first project doing so) and usually I just do everything on the timeline. So MovieClip(root) is familiar to me but I guess it's not the right thing to do here.
Is there a way I can access vars from Main.as?
-----SOLVED-----
I realised MovieClip(root) did work all along but I was just calling on the array before the array was being defined in Main.as. I put a delay on calling graphArray and it worked.
Not sure how that makes sense though because the graphArray is the first thing I've defined in the whole main.as class
Try using this instead
MovieClip(this.root)
This works for me on a test that you can see here:
http://marksost.com/test/as3arrayaccess/
And the source files here:
http://marksost.com/test/as3arrayaccess/test.zip
Is it possible to get a reference to a Silverlight method purely by name from Javascript, and then invoke it? With pure Javascript objects you would be something like this:
var f = theObj["theMethodName"];
f.call(theObj, "an arg");
But treating a Silverlight object as an associative array doesn't seem work.
I'm guessing I could probably use Eval as a last resort, but I'd rather avoid it.
The question is on how to call a Silverlight function from Javascript by name. You can easily call methods on an object directly by enabling a method for scripting using the ScriptableMember attribute, but you can't invoke it as a string directly.
I think you're stuck with eval.
HtmlPage.Window.Invoke("theMethodName", "An arg");
OR
var obj = HtmlPage.Document.GetElementByID("theObj");
obj.Invoke("theMethodName", "an Arg");
...
Ah, re-reading it...no, no access to the reflection API. You'd have to expose it formally. Its still a managed object...just exposed as an 'object' in JScript. So not the same as a prototype object.
This works:
theObj["theMethodName"]("an arg");
But this does not:
theObj["theMethodName"].apply(null, "an arg");
at least I didn't manage to use apply (and call) :(
I only wanted to allow one instance of my C extension class to be made, so I wanted to include the singleton module.
void Init_mousetest() {
VALUE mouseclass = rb_define_class("MyMouse",rb_cObject);
rb_require("singleton");
VALUE singletonmodule = rb_const_get(rb_cObject,rb_intern("Singleton"));
rb_include_module(mouseclass,singletonmodule);
rb_funcall(singletonmodule,rb_intern("included"),1,mouseclass);
### ^ Why do I need this line here?
rb_define_method(mouseclass,"run",method_run,0);
rb_define_method(mouseclass,"spawn",method_spawn,0);
rb_define_method(mouseclass,"stop",method_stop,0);
}
As I understand it, what that line does is the same as Singleton.included(MyMouse), but if I try to invoke that, I get
irb(main):006:0> Singleton.included(MyMouse)
NoMethodError: private method `included' called for Singleton:Module
from (irb):6
from C:/Ruby19/bin/irb:12:in `<main>'
Why does rb_include_module behave differently than I would expect it to? Also any tangential discussions/explanations or related articles are appreciated. Ruby beginner here.
Also it seems like I could have just kept my extension as simple as possible and just hack some kind of interface later on to ensure I only allow one instance. Or just put my mouse related methods into a module... Any of that make sense?
according to http://www.groupsrv.com/computers/about105620.html the rb_include_module() is actually just Module#append_features.
Apparently Module#include calls Module#append_features and Module#included. So in our C code we must also call included. Since clearly something important happens there.