TVariantField class

In unit DB

Field class for native variant data.

Declaration

pascal

TVariantField = class(TField)

Inheritance

Description

TVariantField is the class used when a dataset must manage native variant-typed data. ( DataType equals ftVariant). It initializes some of the properties of the TField class and overrides some of its methods to be able to work with variant data.

It should never be necessary to create an instance of TVariantField manually, a field of this class will be instantiated automatically for each variant field when a dataset is opened.

Methods

`CheckTypeSize`	protected
`GetAsBoolean`	protected
`SetAsBoolean`	protected
`GetAsDateTime`	protected
`SetAsDateTime`	protected
`GetAsFloat`	protected
`SetAsFloat`	protected
`GetAsInteger`	protected
`SetAsInteger`	protected
`GetAsString`	protected
`SetAsString`	protected
`GetAsWideString`	protected
`SetAsWideString`	protected
`GetAsVariant`	protected
`SetVarValue`	protected
`GetDefaultWidth`	protected
`Create`	public	Create a new instance of the TVariantField class.

Inherited

From TField (130)

AccessError Alignment AsAnsiString AsBCD AsBoolean AsBytes AsCurrency AsDateTime AsExtended AsFloat AsInteger AsLargeInt AsLongint AsLongWord Assign AssignValue AsSingle AsString AsUnicodeString AsUTF8String AsVariant AsWideString AttributeSet Bind Calculated CanModify Change CheckInactive Clear ConstraintErrorMessage CurValue CustomConstraint DataChanged DataSet DataSize DataType DefaultExpression Destroy DisplayLabel DisplayName DisplayText DisplayWidth EditMask EditMaskPtr FieldDef FieldKind FieldName FieldNo FocusControl FreeBuffers GetAsAnsiString GetAsBCD GetAsBytes GetAsCurrency GetAsExtended GetAsLargeInt GetAsLongint GetAsLongWord GetAsSingle GetAsUnicodeString GetAsUTF8String GetCanModify GetClassDesc GetCurValue GetData GetDataSize GetDisplayName GetIsNull GetNewValue GetOldValue GetParentComponent GetText HasConstraints HasParent ImportedConstraint Index IsBlob IsIndexField IsNull IsValidChar KeyFields Lookup LookupCache LookupDataSet LookupKeyFields LookupList LookupResultField NewValue Notification Offset OldValue OnChange OnGetText OnSetText OnValidate Origin ParentField PropertyChanged ProviderFlags ReadOnly ReadState RefreshLookupList Required SetAsAnsiString SetAsBCD SetAsBytes SetAsCurrency SetAsExtended SetAsLargeInt SetAsLongint SetAsLongWord SetAsSingle SetAsUnicodeString SetAsUTF8String SetAsVariant SetData SetDataset SetDataType SetFieldType SetNewValue SetParentComponent SetParentField SetSize SetText Size Text Validate ValidChars Value Visible

From TComponent (69)

_AddRef _Release BeforeDestruction CanObserve ChangeName ComObject ComponentCount ComponentIndex Components ComponentState ComponentStyle DefineProperties DesignInfo DestroyComponents Destroying ExecuteAction FindComponent FreeNotification FreeOnRelease GetChildOwner GetChildParent GetChildren GetDeltaStreams GetEnumerator GetIDsOfNames GetNamePath GetObservers GetOwner GetTypeInfo GetTypeInfoCount iicrGetComponent InsertComponent Invoke IsImplementorOf Loaded Loading Name ObserverAdded Observers OnGetDeltaStreams Owner PaletteCreated QueryInterface ReadDeltaState ReadDeltaStream ReferenceInterface RemoveComponent RemoveFreeNotification RemoveFreeNotifications SafeCallException SetAncestor SetChildOrder SetDesigning SetDesignInstance SetInline SetName SetSubComponent Tag ToString TToStringNameMode UpdateAction Updated UpdateRegistry Updating ValidateContainer ValidateInsert ValidateRename VCLComObject WriteState

From TPersistent (4)

AssignTo FPOAttachObserver FPODetachObserver FPONotifyObservers

From TObject (37)

AfterConstruction CheckDisposed ClassInfo ClassName ClassNameIs ClassParent ClassType CleanupInstance DefaultHandler DefaultHandlerStr Dispatch DispatchStr Disposed DisposeOf Equals FieldAddress Free FreeInstance GetDisposed GetHashCode GetInterface GetInterfaceByStr GetInterfaceEntry GetInterfaceEntryByStr GetInterfaceTable GetInterfaceWeak GetLastCastErrorInfo InheritsFrom InitInstance InstanceSize MethodAddress MethodName newinstance QualifiedClassName StringMessageTable SystemHasExtendedRTTI UnitName

An experiment, built from development snapshots. Not the official Free Pascal or Lazarus documentation.