Interacting with GD Script from C# (And The Reverse)

First we will need to create a var we will call it GD Script and we will assign it using find node. From here we can use the Call method followed by the functions name since we dont have a function to call yet lets just leave it blank.

public override void _Ready()
    {
var gdscript = FindNode("GDScript");
var returndata = gdscript.Call("from_cs", "Hello C# worked!");
GD.Print(returndata);
}

	func from_cs(name):
		print(name)
		return "from_cs worked!"

Now that we have our C# function set up lets go over to our GD Script script and lets add a function. This function will take in a value we will call it name and it will print that name. If we run our project it will go ahead and print “hello C# worked!” and it will take that return data from cs worked and print that value!

Lets go back to our GDScriptSample.GD file and add a static function called print data(data) and we will go ahead and print the data.

	static func printData(data):
		print(data)

We will now go to our C# script, go into our ready fucntion and add in some code to load our script with ResourceLoader. When loading our script from resources we need to cast it using the as keyword, from here we can call the function we want using the call function like we did above!

Script gdclass = ResourceLoader.Load("res://GDScriptSample.gd") as Script;
gdclass.Call("printData", "Print Data Has Worked!");

From here you should see it work!

Lets create a C# script and call it CSharpExample.cs we will create a few functions for this the first one will only print the values that are sent to it.

    public bool printCS(string print){
        GD.Print(print);
        return true;
    }

func _ready():
		var cs_node = $CSharp
		var ret = cs_node.printCS("hello from GD script")
		print(ret)

Much like before we need to go ahead and get a reference to our CSharp node. Once we have that we can go ahead and call it by calling the method itself. The nice thing about GD Script is it will automatically wrap our C# function so we don’t have to.

Once we run this function it will go ahead and print hello from GD script meaning it worked! You may notice that the GD Script scripts seem to run before the C# scripts in the execution order! This is interesting and a good thing to know!

public static void PrintCSDemo(string print){
        GD.Print(print);
}

From here lets open up our CSharpExample.cs and add the following to the script.

This will allow us to have the function as a static function and allow it to be called without a node.

Much like before we can go to our GDScriptSample.gd and add the following to our ready function. This will allow us to load the resource script and call our function directly! This is very useful since we wont need to have our script in our scene to call it!

You can see it works!

var cs_class = preload("res://CSharpExample.cs")
cs_class.PrintCSDemo("hell from Static GD Script")

CSharpExample.cs

using Godot;
using System;

public class CSharpExample : Node2D
{
    // Declare member variables here. Examples:
    // private int a = 2;
    // private string b = "text";

    // Called when the node enters the scene tree for the first time.
    public override void _Ready()
    {
        
    }

//  // Called every frame. 'delta' is the elapsed time since the previous frame.
//  public override void _Process(float delta)
//  {
//      
//  }

    public bool printCS(string print){
        GD.Print(print);
        return true;
    }

    public static void PrintCSDemo(string print){
        GD.Print(print);
    }
}

ToGDScript.CS

using Godot;
using System;

public class ToGDScript : Node2D
{
    // Declare member variables here. Examples:
    // private int a = 2;
    // private string b = "text";

    // Called when the node enters the scene tree for the first time.
    public override void _Ready()
    {
        var gdscript = FindNode("GDScript");
        var returndata = gdscript.Call("from_cs", "Hello C# worked!");
        GD.Print(returndata);
        Script gdclass = ResourceLoader.Load("res://GDScriptSample.gd") as Script;
        gdclass.Call("printData", "Print Data Has Worked!");
        
    }

//  // Called every frame. 'delta' is the elapsed time since the previous frame.
//  public override void _Process(float delta)
//  {
//      
//  }
}

GDScriptSample.gd

class GDScriptSample extends Node2D:

	# Declare member variables here. Examples:
	# var a = 2
	# var b = "text"


	# Called when the node enters the scene tree for the first time.
	func _ready():
		var cs_node = $CSharp
		var ret = cs_node.printCS("hello from GD script")
		print(ret)
		var cs_class = preload("res://CSharpExample.cs")
		cs_class.PrintCSDemo("hell from Static GD Script")
		pass # Replace with function body.


	# Called every frame. 'delta' is the elapsed time since the previous frame.
	#func _process(delta):
	#	pass

	func from_cs(name):
		print(name)
		return "from_cs worked!"

	static func printData(data):
		print(data)