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C# Variant

For a detailed explanation of Variant in general, see the Variant documentation page.

Godot.Variant is used to represent Godot's native Variant type. Any Variant-compatible type can be converted from/to it. We recommend avoiding Godot.Variant unless it is necessary to interact with untyped engine APIs. Take advantage of C#'s type safety when possible.

Any of Variant.As{TYPE} methods or the generic Variant.As<T> method can be used to convert a Godot.Variant to a C# type. Since the Godot.Variant type contains implicit conversions defined for all the supported types, calling these methods directly is usually not necessary.

Use CreateFrom method overloads or the generic Variant.From<T> method to convert a C# type to a Godot.Variant.

备注

Since the Variant type in C# is a struct, it can't be null. To create a "null" Variant use the default keyword or the parameterless constructor.

Variant-compatible types

• All the built-in value types, except decimal, nint and nuint.

• string.

• Classes derived from GodotObject.

• Collections types defined in the Godot.Collections namespace.

Full list of Variant types and their equivalent C# type:

Variant.Type	C# Type
Nil	null (Not a type)
Bool	bool
Int	long (Godot stores 64-bit integers in Variant)
Float	double (Godot stores 64-bit floats in Variant)
String	string
Vector2	Godot.Vector2
Vector2I	Godot.Vector2I
Rect2	Godot.Rect2
Rect2I	Godot.Rect2I
Vector3	Godot.Vector3
Vector3I	Godot.Vector3I
Transform2D	Godot.Transform2D
Vector4	Godot.Vector4
Vector4I	Godot.Vector4I
Plane	Godot.Plane
Quaternion	Godot.Quaternion
Aabb	Godot.Aabb
Basis	Godot.Basis
Transform3D	Godot.Transform3D
Projection	Godot.Projection
Color	Godot.Color
StringName	Godot.StringName
NodePath	Godot.NodePath
Rid	Godot.Rid
Object	Godot.GodotObject or any derived type.
Callable	Godot.Callable
Signal	Godot.Signal
Dictionary	Godot.Collections.Dictionary
Array	Godot.Collections.Array
PackedByteArray	byte[]
PackedInt32Array	int[]
PackedInt64Array	long[]
PackedFloat32Array	float[]
PackedFloat64Array	double[]
PackedStringArray	string[]
PackedVector2Array	Godot.Vector2[]
PackedVector3Array	Godot.Vector3[]
PackedColorArray	Godot.Color[]

警告

Godot uses 64-bit integers and floats in Variant. Smaller integer and float types such as int, short and float are supported since they can fit in the bigger type. Be aware that an implicit conversion is performed so using the wrong type will result in potential precision loss.

警告

Enums are supported by Godot.Variant since their underlying type is an integer type which are all compatible. However, implicit conversions don't exist, enums must be manually converted to their underlying integer type before they can converted to/from Godot.Variant or use the generic Variant.As<T> and Variant.From<T> methods to convert them.

enum MyEnum { A, B, C }

Variant variant1 = (int)MyEnum.A;
MyEnum enum1 = (MyEnum)(int)variant1;

Variant variant2 = Variant.From(MyEnum.A);
MyEnum enum2 = variant2.As<MyEnum>();

Using Variant in a generic context

When using generics, you may be interested in restricting the generic T type to be only one of the Variant-compatible types. This can be achieved using the [MustBeVariant] attribute.

public void MethodThatOnlySupportsVariants<[MustBeVariant] T>(T onlyVariant)
{
    // Do something with the Variant-compatible value.
}

Combined with the generic Variant.From<T> allows you to obtain an instance of Godot.Variant from an instance of a generic T type. Then it can be used in any API that only supports the Godot.Variant struct.

public void Method1<[MustBeVariant] T>(T variantCompatible)
{
    Variant variant = Variant.From(variantCompatible);
    Method2(variant);
}

public void Method2(Variant variant)
{
    // Do something with variant.
}

In order to invoke a method with a generic parameter annotated with the [MustBeVariant] attribute, the value must be a Variant-compatible type or a generic T type annotated with the [MustBeVariant] attribute as well.

public class ObjectDerivedClass : GodotObject { }

public class NonObjectDerivedClass { }

public void Main<[MustBeVariant] T1, T2>(T1 someGeneric1, T2 someGeneric2)
{
    MyMethod(42); // Works because `int` is a Variant-compatible type.
    MyMethod(new ObjectDerivedClass()); // Works because any type that derives from `GodotObject` is a Variant-compatible type.
    MyMethod(new NonObjectDerivedClass()); // Does NOT work because the type is not Variant-compatible.
    MyMethod(someGeneric1); // Works because `T1` is annotated with the `[MustBeVariant]` attribute.
    MyMethod(someGeneric2); // Does NOT work because `T2` is NOT annotated with the `[MustBeVariant]` attribute.
}

public void MyMethod<[MustBeVariant] T>(T variant)
{
    // Do something with variant.
}