Class Node

The base class for all user-accessible nodes in a graph.

Inheritance

object

Node

BlockNode

ContextNode

Implements

INode

Inherited Members

object.Equals(object)

object.Equals(object, object)

object.GetHashCode()

object.GetType()

object.MemberwiseClone()

object.ReferenceEquals(object, object)

object.ToString()

Namespace: Unity.GraphToolkit.Editor

Assembly: Unity.GraphToolkit.Editor.dll

Syntax

[Serializable]
public abstract class Node : INode

Remarks

Inherit from this class to define custom node types that appear in the graph. The Node class provides lifecycle hooks, serialization support, and the structure needed to define ports, UI behaviors, and custom logic. This class forms the foundation of all user-defined nodes in a graph-based tool, including variable nodes, context nodes, and subgraph nodes.

To create a custom node, derive from Node, define its input and output ports using a port builder in OnDefinePorts(IPortDefinitionContext), and define its INodeOptions in OnDefineOptions(IOptionDefinitionContext).

This class is used in combination with other types like INode, IPort, and Graph to construct and manage node-based workflows.

See also:

• INode for the interface this class implements
• ContextNode and BlockNode for composition patterns
• IVariableNode for how to work with variable-based nodes
• ISubgraphNode for how to work with subgraph-based nodes

Properties

inputPortCount

The number of input ports on the node.

Declaration

public int inputPortCount { get; }

Property Value

Type	Description
int

nodeOptionCount

The number of node options defined in the node.

Declaration

public int nodeOptionCount { get; }

Property Value

Type	Description
int

nodeOptions

The node options defined on this node.

Declaration

public IEnumerable<INodeOption> nodeOptions { get; }

Property Value

Type	Description
IEnumerable<INodeOption>

outputPortCount

The number of output ports on the node.

Declaration

public int outputPortCount { get; }

Property Value

Type	Description
int

Methods

DefineNode()

Defines the structure of the node by building its ports and options.

Declaration

public void DefineNode()

Remarks

This method calls both OnDefineOptions(IOptionDefinitionContext) and OnDefinePorts(IPortDefinitionContext) to allow custom definition of the node.

GetInputPort(int)

Retrieves an input port using its index.

Declaration

public IPort GetInputPort(int index)

Parameters

Type	Name	Description
int	index	The index of the input port.

Returns

Type	Description
IPort	The input port at the specified index.

Remarks

The index is zero-based. The list of input ports is ordered according to their display order in the node.

GetInputPortByName(string)

Retrieves an input port using its name.

Declaration

public IPort GetInputPortByName(string name)

Parameters

Type	Name	Description
string	name	The unique name of the input port within this node.

Returns

Type	Description
IPort	The input port with the specified name.

Remarks

The input port's name is unique within the node's input ports and node options.

GetInputPorts()

Retrieves all input ports on the node in the order they are displayed.

Declaration

public IEnumerable<IPort> GetInputPorts()

Returns

Type	Description
IEnumerable<IPort>	An IEnumerable of input ports.

GetNodeOption(int)

Retrieves a node option using its zero-based index.

Declaration

public INodeOption GetNodeOption(int index)

Parameters

Type	Name	Description
int	index	Index of the node option, based on display order.

Returns

Type	Description
INodeOption	The node option at the specified index.

Remarks

The index is zero-based.

Exceptions

Type	Condition
IndexOutOfRangeException	Thrown if the index is out of bounds.

GetNodeOptionByName(string)

Retrieves a node option using its name.

Declaration

public INodeOption GetNodeOptionByName(string name)

Parameters

Type	Name	Description
string	name	The unique name of the node option.

Returns

Type	Description
INodeOption	The node option with the specified name, or null if none is found.

Remarks

The node option's name is unique within the node's input ports and node options.

GetOutputPort(int)

Retrieves an output port using its index in the displayed order.

Declaration

public IPort GetOutputPort(int index)

Parameters

Type	Name	Description
int	index	The zero-based index of the output port.

Returns

Type	Description
IPort	The output port at the specified index.

Remarks

The index is zero-based. The list of output ports is ordered according to their display order in the node.

GetOutputPortByName(string)

Retrieves an output port using its name.

Declaration

public IPort GetOutputPortByName(string name)

Parameters

Type	Name	Description
string	name	The unique name of the output port within this node.

Returns

Type	Description
IPort	The output port with the specified name, or null if no match is found.

Remarks

The output port's name is unique within the node's output ports.

GetOutputPorts()

Retrieves all output ports on the node in the order they are displayed.

Declaration

public IEnumerable<IPort> GetOutputPorts()

Returns

Type	Description
IEnumerable<IPort>	An IEnumerable of output ports.

OnDefineOptions(IOptionDefinitionContext)

Called during DefineNode() to define the options available on the node.

Declaration

protected virtual void OnDefineOptions(Node.IOptionDefinitionContext context)

Parameters

Type	Name	Description
Node.IOptionDefinitionContext	context	Provides methods for defining node options.

Remarks

This method is called before OnDefinePorts(IPortDefinitionContext). Override this method to add node options using the provided Node.IOptionDefinitionContext.

Examples

protected override void OnDefineOptions(IOptionDefinitionContext context)
{
    context.AddNodeOption<bool>(
        optionName: "My Bool",
        optionDisplayName: "myBoolId");

    context.AddNodeOption(
        optionName: "Label",
        dataType: typeof(string),
        optionDisplayName: "labelId",
        tooltip: "A label.",
        defaultValue: "Default Value");
}

OnDefinePorts(IPortDefinitionContext)

Called during DefineNode() to define the input and output ports of the node.

Declaration

protected virtual void OnDefinePorts(Node.IPortDefinitionContext context)

Parameters

Type	Name	Description
Node.IPortDefinitionContext	context	Provides methods for defining input and output ports.

Remarks

This method is called after OnDefineOptions(IOptionDefinitionContext) and is used to declare the structure of the node's connectivity. Use the provided Node.IPortDefinitionContext to define input and output ports using a builder pattern. The port builder pattern enables fluent configuration of ports by chaining methods such as WithDisplayName, WithDefaultValue, or WithConnectorUI, followed by Build() to finalize the port. The portName parameter passed to AddInputPort or AddOutputPort serves as the port's unique identifier. The portName parameter must be unique within its direction (input or output) on the node and is also used as the display name unless you explicitly call WithDisplayName. You also use the portName identifier to call GetInputPortByName(string).

Examples

protected override void OnDefinePorts(IPortDefinitionContext context)
{
    var inputPort = context.AddInputPort<string>("stringInput")
        .WithDisplayName("String Input")
        .WithDefaultValue("Default Value")
        .Build();

    var outputPort = context.AddOutputPort("myOutput")
        .WithDisplayName("My Output Port")
        .WithDataType(typeof(float))
        .WithConnectorUI(PortConnectorUI.Arrowhead)
        .Build();
}

OnDisable()

Called when the node is removed or when the graph is disabled.

Declaration

public virtual void OnDisable()

Remarks

Use this method to perform any cleanup logic.

OnEnable()

Called when the node is created or when the graph is enabled.

Declaration

public virtual void OnEnable()

Remarks

Use this method to perform initialization logic.

Implements

INode