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UPROPERTY - Epic Wiki

# UPROPERTY

# Contents

# Description

UProperty variables are declared using standard C++ syntax with additional descriptors, such as variable specifiers and metadata placed above the declaration.

UPROPERTY([specifier, specifier, ...], [meta=(key=value, key=value, ...)]) Type VariableName;

# Valid Specifiers

Pro Tip: You can use `using namespace UP;` to have these keywords as enums thus potentially have them auto-complete.

Pro Tip 2: All valid UPROPERTY specifiers are listed as enum values in "ObjectBase.h", Line 728

# Const

This property is const and should be exported as const.

# Config

Property should be loaded/saved to ini file as permanent profile.

# GlobalConfig

Same as above but load config from base class, not subclass.

# Localized

Property should be loaded as localizable text. Implies ReadOnly.

# Transient

Property is transient: shouldn't be saved, zero-filled at load time.

# DuplicateTransient

Property should always be reset to the default value during any type of duplication (copy/paste, binary duplication, etc.)

# NonPIETransient

Property should always be reset to the default value during any type of duplication (copy/paste, binary duplication, etc.)

# Ref

Value is copied out after function call. Only valid on function param declaration.

# Export

Object property can be exported with it's owner.

# EditInline

Edit this object reference inline in the editor.

# NoClear

Hide clear (and browse) button in the editor.

# EditFixedSize

Indicates that elements of an array can be modified, but its size cannot be changed.

# Replicated

Property is relevant to network replication.

# ReplicatedUsing

Property is relevant to network replication. Notify actors when a property is replicated (usage: ReplicatedUsing=FunctionName).

# RepRetry

Retry replication of this property if it fails to be fully sent (e.g. object references not yet available to serialize over the network)

# NotReplicated

Skip replication (only for struct members and parameters in service request functions).

# Interp

Interpolatable property for use with matinee. Always user-settable in the editor.

# NonTransactional

Property isn't transacted.

# Instanced

Property is a component reference. Implies EditInline and Export.

# BlueprintAssignable

MC Delegates only. Property should be exposed for assigning in blueprints.

# Category

Specifies the category of the property. Usage: Category=CategoryName.

# SimpleDisplay

Properties appear visible by default in a details panel

# AdvancedDisplay

Properties are in the advanced dropdown in a details panel

# EditAnywhere

Indicates that this property can be edited by property windows in the editor

# EditInstanceOnly

Indicates that this property can be edited by property windows, but only on instances, not on archetypes

# EditDefaultsOnly

Indicates that this property can be edited by property windows, but only on archetypes

# VisibleAnywhere

Indicates that this property is visible in property windows, but cannot be edited at all

# VisibleInstanceOnly

Indicates that this property is only visible in property windows for instances, not for archetypes, and cannot be edited

# VisibleDefaultsOnly

Indicates that this property is only visible in property windows for archetypes, and cannot be edited

# BlueprintReadOnly

This property can be read by blueprints, but not modified.

# BlueprintReadWrite

This property can be read or written from a blueprint.

# AssetRegistrySearchable

The AssetRegistrySearchable keyword indicates that this property and it's value will be automatically added to the asset registry for any asset class instances containing this as a member variable. It is not legal to use on struct properties or parameters.

# SaveGame

Property should be serialized for save game.

# BlueprintCallable

MC Delegates only. Property should be exposed for calling in blueprint code

# BlueprintAuthorityOnly

MC Delegates only. This delegate accepts (only in blueprint) only events with BlueprintAuthorityOnly.

# TextExportTransient

Property shouldn't be exported to text format (e.g. copy/paste)

# Valid Meta Properties

# DisplayName

Sets the display name for the property in the editor. The default value is the variable name with a space before each capital. For example 'MyVariableName' would show up as 'My Variable Name'

Usage DisplayName = "My Display Name"

# AllowAbstract

Used for FStringClassReference properties. Indicates whether abstract class types should be shown in the class picker.

# AllowedClasses

Used for FStringAssetReference properties. Comma delimited list that indicates the class type(s) of assets to be displayed in the asset picker.

# AllowPreserveRatio

Used for FVector properties. It causes a ratio lock to be added when displaying this property in details panels.

# ArrayClamp

Used for integer properties. Clamps the valid values that can be entered in the UI to be between 0 and the length of the array specified.

# ClampMin

Used for float and integer properties. Specifies the minimum value that may be entered for the property.

# ClampMax

Used for float and integer properties. Specifies the maximum value that may be entered for the property.

# DisplayThumbnail

Indicates that the property is an asset type and it should display the thumbnail of the selected asset.

# EditCondition

Species a boolean property that is used to indicate whether editing of this property is disabled.

# ExactClass

Used for FStringAssetReference properties in conjunction with AllowedClasses. Indicates whether only the exact classes specified in AllowedClasses can be used or whether subclasses are valid.

# ExposeFunctionCategories

[Undocumented]

# ExposeOnSpawn

Specifies whether the property should be exposed on a Spawn Actor for the class type.

# FixedIncrement

[Undocumented]

# HideAlphaChannel

Used for FColor and FLinearColor properties. Indicates that the Alpha property should be hidden when displaying the property widget in the details.

# IsBlueprintBaseOnly

Used for FStringClassReference properties. Indicates whether only blueprint classes should be shown in the class picker.

# OnlyPlaceable

Used for Subclass properties. Indicates whether only placeable classes should be shown in the class picker.

# MakeEditWidget

When used with certain objects such as an FVector, you get to use an "edit widget" within the editor to transform the object in space.

# MakeStructureDefaultValue

For properties in a structure indicates the default value of the property in a blueprint make structure node.

# MetaClass

Used FStringClassReference properties. Indicates the parent class that the class picker will use when filtering which classes to display.

# Multiple

[Undocumented]

# MultiLine

Used for FString and FText properties. Indicates that the edit field should be multi-line, allowing entry of newlines.

# NoElementDuplicate

Used for array properties. Indicates that the duplicate icon should not be shown for entries of this array in the property panel.

# NoSpinbox

Used for integer and float properties. Indicates that the spin box element of the number editing widget should not be displayed.

# FilePathFilter

Used by FFilePath properties. Indicates the path filter to display in the file picker.

# RelativePath

Used by FDirectoryPath properties.

# RelativeToGameContentDir

Used by FDirectoryPath properties.

# ShowOnlyInnerProperties

[Undocumented]

# SliderExponent

[Undocumented]

# UIMin

Used for float and integer properties. Specifies the lowest that the value slider should represent.

# UIMax

Used for float and integer properties. Specifies the highest that the value slider should represent.

# Related

UCLASS, UFUNCTION, USTRUCT, UMETA, UPARAM, UENUM, UDELEGATE

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