C# API differences to GDScript

This is a (incomplete) list of API differences between C# and GDScript.

General differences

As explained in the C# basics, C# generally uses PascalCase instead of the snake_case used in GDScript and C++.

Global scope

Global functions and some constants had to be moved to classes, since C# does not allow declaring them in namespaces. Most global constants were moved to their own enums.

Constants

Global constants were moved to their own enums. For example, ERR_* constants were moved to the Error enum.

Special cases:

GDScript	C#
`SPKEY`	`GD.SpKey`
`TYPE_*`	`Variant.Type` enum
`OP_*`	`Variant.Operator` enum

Math functions

Math global functions, like abs, acos, asin, atan and atan2, are located under Mathf as Abs, Acos, Asin, Atan and Atan2. The PI constant can be found as Mathf.Pi.

Random functions

Random global functions, like rand_range and rand_seed, are located under GD. Example: GD.RandRange and GD.RandSeed.

Other functions

Many other global functions like print and var2str are located under GD. Example: GD.Print and GD.Var2Str.

Exceptions:

GDScript	C#
`weakref(obj)`	`Object.WeakRef(obj)`
`is_instance_valid(obj)`	`Object.IsInstanceValid(obj)`

Tips

Sometimes it can be useful to use the using static directive. This directive allows to access the members and nested types of a class without specifying the class name.

Example:

using static Godot.GD;

public class Test
{
    static Test()
    {
        Print("Hello"); // Instead of GD.Print("Hello");
    }
}

Export keyword

Use the [Export] attribute instead of the GDScript export keyword. This attribute can also be provided with optional PropertyHint and hintString parameters. Default values can be set by assigning a value.

Example:

using Godot;

public class MyNode : Node
{
    [Export]
    private NodePath _nodePath;

    [Export]
    private string _name = "default";

    [Export(PropertyHint.Range, "0,100000,1000,or_greater")]
    private int _income;

    [Export(PropertyHint.File, "*.png,*.jpg")]
    private string _icon;
}

Signal keyword

Use the [Signal] attribute to declare a signal instead of the GDScript signal keyword. This attribute should be used on a delegate, whose name signature will be used to define the signal.

[Signal]
delegate void MySignal(string willSendsAString);

onready keyword

GDScript has the ability to defer the initialization of a member variable until the ready function is called with onready (cf. onready keyword). For example:

onready var my_label = get_node("MyLabel")

However C# does not have this ability. To achieve the same effect you need to do this.

private Label _myLabel;

public override void _Ready()
{
    _myLabel = GetNode<Label>("MyLabel");
}

Singletons

Singletons are available as static classes rather than using the singleton pattern. This is to make code less verbose than it would be with an Instance property.

Example:

Input.IsActionPressed("ui_down")

However, in some very rare cases this is not enough. For example, you may want to access a member from the base class Godot.Object, like Connect. For such use cases we provide a static property named Singleton that returns the singleton instance. The type of this instance is Godot.Object.

Example:

Input.Singleton.Connect("joy_connection_changed", this, nameof(Input_JoyConnectionChanged));

String

Use System.String (string). Most of Rebel Engine's String methods are provided by the StringExtensions class as extension methods.

Example:

string upper = "I LIKE SALAD FORKS";
string lower = upper.ToLower();

There are a few differences, though:

erase: Strings are immutable in C#, so we cannot modify the string passed to the extension method. For this reason, Erase was added as an extension method of StringBuilder instead of string. Alternatively, you can use string.Remove.
IsSubsequenceOf/IsSubsequenceOfi: An additional method is provided, which is an overload of IsSubsequenceOf, allowing you to explicitly specify case sensitivity:

str.IsSubsequenceOf("ok"); // Case sensitive
str.IsSubsequenceOf("ok", true); // Case sensitive
str.IsSubsequenceOfi("ok"); // Case insensitive
str.IsSubsequenceOf("ok", false); // Case insensitive

Match/Matchn/ExprMatch: An additional method is provided besides Match and Matchn, which allows you to explicitly specify case sensitivity:

str.Match("*.txt"); // Case sensitive
str.ExprMatch("*.txt", true); // Case sensitive
str.Matchn("*.txt"); // Case insensitive
str.ExprMatch("*.txt", false); // Case insensitive

Basis

Structs cannot have parameterless constructors in C#. Therefore, new Basis() initializes all primitive members to their default value. Use Basis.Identity for the equivalent of Basis() in GDScript and C++.

The following method was converted to a property with a different name:

GDScript	C#
`get_scale()`	`Scale`

Transform2D

Structs cannot have parameterless constructors in C#. Therefore, new Transform2D() initializes all primitive members to their default value. Please use Transform2D.Identity for the equivalent of Transform2D() in GDScript and C++.

The following methods were converted to properties with their respective names changed:

GDScript	C#
`get_rotation()`	`Rotation`
`get_scale()`	`Scale`

Plane

The following method was converted to a property with a slightly different name:

GDScript	C#
`center()`	`Center`

Rect2

The following field was converted to a property with a slightly different name:

GDScript	C#
`end`	`End`

The following method was converted to a property with a different name:

GDScript	C#
`get_area()`	`Area`

Quat

Structs cannot have parameterless constructors in C#. Therefore, new Quat() initializes all primitive members to their default value. Please use Quat.Identity for the equivalent of Quat() in GDScript and C++.

The following methods were converted to a property with a different name:

GDScript	C#
`length()`	`Length`
`length_squared()`	`LengthSquared`

Array

This is temporary. PoolArrays will need their own types to be used the way they are meant to.

GDScript	C#
`Array`	`Godot.Collections.Array`
`PoolIntArray`	`int[]`
`PoolByteArray`	`byte[]`
`PoolFloatArray`	`float[]`
`PoolStringArray`	`String[]`
`PoolColorArray`	`Color[]`
`PoolVector2Array`	`Vector2[]`
`PoolVector3Array`	`Vector3[]`

Godot.Collections.Array<T> is a type-safe wrapper around Godot.Collections.Array. Use the Godot.Collections.Array<T>(Godot.Collections.Array) constructor to create one.

Dictionary

Use Godot.Collections.Dictionary.

Godot.Collections.Dictionary<T> is a type-safe wrapper around Godot.Collections.Dictionary. Use the Godot.Collections.Dictionary<T>(Godot.Collections.Dictionary) constructor to create one.

Variant

System.Object (object) is used instead of Variant.

Communicating with other scripting languages

This is explained extensively in Cross-language scripting.

Yield

Something similar to GDScript's yield with a single parameter can be achieved with C#'s yield keyword.

The equivalent of yield on signal can be achieved with async/await and Godot.Object.ToSignal.

Example:

await ToSignal(timer, "timeout");
GD.Print("After timeout");

Other differences

preload, as it works in GDScript, is not available in C#. Use GD.Load or ResourceLoader.Load instead.

Other differences:

GDScript	C#
`Color8`	`Color.Color8`
`is_inf`	`float.IsInfinity`
`is_nan`	`float.IsNaN`
`dict2inst`	TODO
`inst2dict`	TODO