Class TCastleComponent

Unit

Declaration

type TCastleComponent = class(TComponent)

Description

Component with various CGE extensions: can be a parent of other non-visual components (to display them in CGE editor and serialize them to files), can be translated, can have custom logic when serializing/deserializing (CustomSerialization).

Note that everywhere in CGE (in particular in editor and when serializing) we handle a standard Pascal TComponent as well. So there's no need to derive all your components from TCastleComponent, so you derive from standard TComponent too. You can use TCastleComponent only if necessary, i.e. only if you need one of the extra features in this class.

Hierarchy

  • TObject
  • TPersistent
  • TComponent
  • TCastleComponent

Overview

Methods

Protected function GetInternalText: String; virtual;
Protected procedure SetInternalText(const Value: String); virtual;
Protected procedure SetName(const Value: TComponentName); override;
Protected procedure TranslateProperties(const TranslatePropertyEvent: TTranslatePropertyEvent); virtual;
Public destructor Destroy; override;
Public procedure CustomSerialization(const SerializationProcess: TSerializationProcess); virtual;
Public function PropertySections(const PropertyName: String): TPropertySections; virtual;
Public procedure SetTransient;
Public procedure AddNonVisualComponent(const NonVisualComponent: TComponent);
Public procedure InsertNonVisualComponent(const Index: Integer; const NonVisualComponent: TComponent);
Public procedure RemoveNonVisualComponent(const NonVisualComponent: TComponent);
Public function NonVisualComponentsIndexOf(const NonVisualComponent: TComponent): Integer;
Public function NonVisualComponentsCount: Integer;
Public function NonVisualComponentsEnumerate: TNonVisualComponentsEnumerator;
Public function ValueIsStreamed: Boolean; virtual;
Public procedure DesignerInfo(const SList: TStrings); virtual;
Public procedure DesignerWarnings(const SList: TStrings); virtual;

Properties

Public property NonVisualComponents [const Index: Integer]: TComponent read GetNonVisualComponents;
Public property IsLoading: Boolean read FIsLoading;

Description

Methods

Protected function GetInternalText: String; virtual;

This item has no description.

Protected procedure SetInternalText(const Value: String); virtual;

This item has no description.

Protected procedure SetName(const Value: TComponentName); override;

This item has no description.

Protected procedure TranslateProperties(const TranslatePropertyEvent: TTranslatePropertyEvent); virtual;

Enumerate all properties that are possible to translate in this component. E.g. in TCastleLabel it will return TCastleLabel.Caption, in TCastleEdit it will return TCastleEdit.Text and TCastleEdit.Placeholder.

Returns only non-empty properties, thus assuming that if current (by convention, English) text is empty, then there is no point in translating it. Moreover descendants may define boolean properties to exclude particular text from translating, e.g. TCastleLabel.CaptionTranslate, TCastleEdit.TextTranslate, TCastleEdit.PlaceholderTranslate.

It is not recursive (it doesn't enumerate children properties). Use global TranslateProperties procedure to call this on a hierarchy of TComponent.

You usually don't want to call this method (it is called by other engine routines). But you may find it useful to override this, if you define new component.

Public destructor Destroy; override;

This item has no description.

Public procedure CustomSerialization(const SerializationProcess: TSerializationProcess); virtual;

Override this method to call various methods of SerializationProcess, which in turn allows to serialize/deserialize things that are not published. This allows to serialize/deserialize with more freedom, e.g. to serialize/deserialize some private field.

Public function PropertySections(const PropertyName: String): TPropertySections; virtual;

Section where to show property in the editor.

Public procedure SetTransient;

Ignore this component when serializing parent's TCastleUserInterface.Controls list or TCastleTransform.List, and do not show this component in CGE editor. This simply sets csTransient flag in ComponentStyle.

This is useful for children that are automatically managed by the parent, and should not be modified by user code. For example, TCastleCheckbox is internally composed from TCastleImageControl and TCastleLabel children, but we don't want to serialize or even show these children to user.

Note that if you want to prevent this component from serializing as part of TCastleUserInterface.Controls list or TCastleTransform.List, but you still want it to be visible in CGE editor, then make it a "subcomponent" instead, by SetSubComponent(true).

Note that both csSubComponent and csTransient only disable the component serialization as part of parent's lists enumerated by CustomSerialization (see internal TCastleUserInterface.SerializeChildrenEnumerate , TCastleTransform.SerializeChildrenEnumerate, TCastleTransform.SerializeBehaviorsEnumerate).

If you will make the component published in its own property (which is normal for "subcomponents") then it will be serialized anyway, just as part of it's own property (like TCastleScrollView.ScrollArea). So to really avoid serializing a children component make it csSubComponent and/or csTransient, and do not publish it.

Public procedure AddNonVisualComponent(const NonVisualComponent: TComponent);

Add non-visual component to this component. This is used to organize non-visual components in a tree hierarchy, in CGE designs and editor.

See also
NonVisualComponentsCount
Count of components added by AddNonVisualComponent.
NonVisualComponents
Components added by AddNonVisualComponent.
NonVisualComponentsEnumerate
You can enumerate current non-visual components using loop like for C in MyComponent.NonVisualComponentsEnumerate do ....
Public procedure InsertNonVisualComponent(const Index: Integer; const NonVisualComponent: TComponent);

Insert non-visual component to this component. This is used to organize non-visual components in a tree hierarchy, in CGE designs and editor.

See also
NonVisualComponentsCount
Count of components added by AddNonVisualComponent.
NonVisualComponents
Components added by AddNonVisualComponent.
NonVisualComponentsEnumerate
You can enumerate current non-visual components using loop like for C in MyComponent.NonVisualComponentsEnumerate do ....
Public procedure RemoveNonVisualComponent(const NonVisualComponent: TComponent);

Remove component previously added by AddNonVisualComponent.

Public function NonVisualComponentsIndexOf(const NonVisualComponent: TComponent): Integer;

Index of component previously added non-visual component. Returns -1 if component was not found.

Public function NonVisualComponentsCount: Integer;

Count of components added by AddNonVisualComponent.

See also
AddNonVisualComponent
Add non-visual component to this component.
NonVisualComponents
Components added by AddNonVisualComponent.
NonVisualComponentsEnumerate
You can enumerate current non-visual components using loop like for C in MyComponent.NonVisualComponentsEnumerate do ....
Public function NonVisualComponentsEnumerate: TNonVisualComponentsEnumerator;

You can enumerate current non-visual components using loop like for C in MyComponent.NonVisualComponentsEnumerate do .... Do not call this method in other contexts, it is only useful for "for..in" construction.

See also
AddNonVisualComponent
Add non-visual component to this component.
Public function ValueIsStreamed: Boolean; virtual;

Whether the current value of this object should be written to the stream. This should be True if anything inside this object should be serialized (which means it has non-default value or "stored" specifier indicates that it should be serialized).

This is used by CastleComponentSerialize, which is used in Castle Game Engine for all serialization.

In simple cases, this just says whether the current value of this object equals to some default value.

The default implementation of this class returns True (so always write).

Descendants that override this to sometimes return False (so no need to write) must be very careful: any addition of a new field requires extending this method, otherwise new field may not be saved sometimes (when all other fields are default). Descentants of such classes must also be aware of it. This check must include everything that is inside this object in JSON, including subcomponents and children objects (as done e.g. by TSerializationProcess.ReadWriteList). In practice, overriding this method is only reasonable for simple classes that will not change much in the future, like TCastleVector3Persistent.

The name of this method is consistent with TPropertyEditor.ValueIsStreamed in LCL.

Public procedure DesignerInfo(const SList: TStrings); virtual;

Override to add information that should be visible at design-time. Call SList.Add for each new line of information.

Public procedure DesignerWarnings(const SList: TStrings); virtual;

Override to add warnings that should be visible at design-time. Call SList.Add for each new warning.

Properties

Public property NonVisualComponents [const Index: Integer]: TComponent read GetNonVisualComponents;

Components added by AddNonVisualComponent.

Public property IsLoading: Boolean read FIsLoading;

Is the component during deserialization now.

Note: We can't use csLoading in ComponentState because in Delphi it is not possible to control it from CastleComponentSerialize.


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