如何使用LuaInterface从VB.NET调用Lua函数

Question

I have been attempting to figure out how to call a Lua function from a 'pre-compiled' LuaFunction. The general idea is that I want to call a Lua function from C#. I am able to do it the other way around by using Lua.RegisterFunction() however just fine.

What ends up happening is that the callback returns null, aka the actual function does not seem to be read or exists when using 'Lua.LoadFile()'. I am not exactly sure how to set this up though yet.

So to initialize the Lua script in VB.net, I use a class with the following:

Private state As Lua
Private luafunction As LuaFunction

Public Sub New(ByVal playerInstance As PlayerClass)
        Me.playerInstance = playerInstance
        state = New Lua()
        state.RegisterFunction("PrivateMessage", Me, Me.GetType().GetMethod("PrivateMessage"))
        state("playerID") = Me.playerInstance.Index
        luafunction = state.LoadFile(SkillsFolder & "script.lua")
End Sub

luafunction being the pre-compiled script. I want to use LoadFile because it is being called more then once, and LoadFile over DoFile is more efficient.

I have the calling function here:

Public Function ProcessAttack() As Boolean
        Dim luaFunc As LuaFunction = state.GetFunction("AttackProcess")

        If luaFunc IsNot Nothing Then
            Dim processed As Object = luaFunc.Call()
            Return processed(0)
        End If
    Return False
End Function

Obviously luaFunc is nothing/null. Doesn't actually work here. The LUA script is as follows:

function AttackProcess()
   PrivateMessage(playerID, "Test!")
   return true
end

It's a very basic script. The idea is that when the player 'attacks' it should call the Lua script first to see if the function exists and can be handled in Lua, otherwise C# will handle it in a default method of it's choosing. (So if handled, AttackProcess() will return true, and then the C# coding the handles the basic attacking will not be called.)

I have a feeling that Dim luaFunc As LuaFunction = state.GetFunction("AttackProcess") is pretty much trying to search through nothing, I might need to use the variable that is precompiled, which is 'luafunction' to pull it, but I have been stomped on exactly how to get Lua to be called by C#.

Thank you.

Answer 1

I was able to solve this by calling 'DoFile' instead of LoadFile. Apparently the function itself needs to be loaded before you attempt to pull it into a LuaFunction.

For exmaple

If File.Exists(SkillsFolder & "Main\" & playerInstance.ClassName & ".lua") Then
    state.DoFile(SkillsFolder & "Main\" & playerInstance.ClassName & ".lua")
    Dim luaFunc As LuaFunction = state.GetFunction("attack")
    If luaFunc IsNot Nothing Then
        luaAttack = luaFunc
    End If
End If

Now works, and luaAttack ends up with the proper function. You can also use LoadFile, then Call() once, and grab the functions that way as well. The important thing here is that the coding is at least executed ONCE to be able to grab created functions. Loading it only will not work.