C# Events in Lua

ddboarm · 2009-09-15T09:56:23

I am working on a rough prototype Object Creation Engine that is setup up dynamically by Lua script. Initially, I thought this would be easy. But I soon found out different. While enjoyable overall, it has been a challenge trying to convert C snippets to equivalent C#(based on fairly limited "accurate" sources). Besides, many examples only include what the author considers advanced. Here's why this is so drawn out - I want others to understand and possibly implement my procedures. If I'm on the right track, lemme know...and if I'm wrong, I'll expect explanations :). This is a kind of pseudo code I do: Given: // language = C# // lua = new LuaInterface // event Object_OnCreate // event Button_OnClick // txtArray = Control.TextBox {multiline = true} Object_OnCreate(sender, e) { lua.RegisterObject("event.sender", sender); lua.RegisterObject("event.evkey", e.Key); lua.RegisterObject("event.evobj", e.Object); } Button_OnClick(sender, e) { LuaInterface.LuaTable _LTable = (LuaInterface.LuaTable)lua[path]; string[] arrTable = new string[_LTable.Keys.Count]; int ndx = 0; foreach (DictionaryEntry element in _LTable) { string sVal; sVal = element.Key.ToString() + " = " + element.Value.ToString() + '\n'; arrTable.SetValue(sVal, ndx++); } txtArray.Clear(); foreach (object element in arrArray) { txtArray.AppendText(element.ToString()); } } // LuaSnippet event = {} event.sender = "" event.evkey = "" event.evobj = "" So, the Object is created and fires off a delegate event I wrote. As you can see, I register the object with a Lua table named "event". This was to ensure that my Lua function would receive all the correct information when I call it from C#: Given: // language C# lua.DoString("event:Engine_OnObjectCreated()"); // LuaSnippet omni = {} function event:Engine_OnObjectCreated() sKey = { event.evkey} omni[sKey] = {} omni[sKey].Obj = event.evobj end With "omni" being a global table, I am assuming that I can add a new Key [sKey] to the "omni" table, and even a new Key ["Obj"] with the value referencing the newly created object. This process has evolved from fruitless searches on finding an example of getting a Lua function to trigger as a direct result of an event. I know there has got to be an easier way to call this On_Event_Function in Lua. Here is the pseudo code equivalent to I'm looking for: Given: // language C# Button.Click += new OnButtonClickEventHandler( Lua.DoScript("event:Engine_OnObjectCreated()")); // LuaSnippet function event:Engine_OnObjectCreated(sender, e) //c# { txtArray.AppendText(e.Key + "= " e.Value + '\n'); } end Obviously, the C# inside the LuaSnippet is just my way of capturing a message through Lua calling a C# function. Amazing to me, I was able to trace four things in the text results, therefore tracing the object creation, verifying proper reference, and even the type of object through my C# debugger. In my quest to achieve 1 thing, I believe I have succeeded in achieving two things. First, I succeeded in my mission of firing an event in Lua with all the necessary parts -- albeit, not the most efficient method, I am sure. Second, I have a quality testing widget to understand how Lua works and that the table has the correct references. And this, my friends, is what I wanted to share with you all (err, um, y'all for those of us in Texas). After all that, my question really comes down to "Is there a better way for an event to hook up with a Lua function?" Later (and anxiously awaiting replies)... [Edited by - ddboarm on September 11, 2009 4:59:45 PM]

Engines and Middleware Programming

Started by ddboarm September 08, 2009 03:36 PM

11 comments, last by ddboarm 14 years, 7 months ago

iliak

278

September 15, 2009 01:24 AM

Quote:
- Implementation: I know that implementing the C# Script could be very easy and non-problematic in most cases. I am, however, using the VS Express app. I have tried downloading and installing the C# Script. Immediately, I ran into problems with my IDE randomly crashing at the most inopportune moment - at one time causing me to think I might have lost over 350 lines of code. Since I removed/uninstalled the .DLLs, I have no more problems...and I reverted to my first reason for choosing Lua.

Thank you for your response to this thread :)

I was not trying to convince you, just give another opportunity / solution. Just to finish with this, you don't have to download or install any external dll. If you want an example how i do, look at here.

Good luck with you Lua experiences :)

- Iliak -
[ ArcEngine: An open source .Net gaming framework ]
[ Dungeon Eye: An open source remake of Eye of the Beholder II ]

ddboarm

100

Author

September 15, 2009 09:54 AM

So far the 'Lua experience' has been challenging, but rewarding. I have learned a lot and really feel that it is the best way to go. Especially since I intend to allow others to implement new content.

I didn't really take your question as trying to convince me to use C# Script. But I did want to answer your question since I felt me reasoning has merit. :)

ddboarm

100

Author

September 15, 2009 09:56 AM

Quote:Original post by AverageJoeSSU
My Events are from an event system entirely implemented in Lua, If you go to the lua programming gems site you can find it. The guy who wrote the chapter says it is similar to how C# does events.

I basically pass the lua_state* from my engine dll up to LuaInterface, using the other constructor that takes an IntPtr which is a lua state.

that lua_state* contains the API from my engine for lua to create and manipulate game objects / fire and subscribe to events.

I'll have to look into it more then as I really do want to extend some events to the script. Thanks!!!

C# Events in Lua

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