FPDoc Onlineexperiment

TBlobField class

In unit DB

Base class for BLOB field data.

Declaration

pascal

TBlobField = class(TField)

Inheritance

Descends from it: TGraphicField TMemoField TWideMemoField

Description

TBLobField is the class used when a dataset must manage BLOB data. ( DataType equals ftBLOB). It initializes some of the properties of the TField class, and overrides some of its methods to be able to work with BLOB fields. It also serves as parent class for some specialized blob-like field types such as TMemoField, TWideMemoField or TGraphicField

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

See also

Properties

`BlobSize`	public	Size of the current blob.
`Modified`	public	Has the field's contents been modified.
`Value`	public	Return the field's contents as a string.
`Transliterate`	public	Should the contents of the field be transliterated.
`BlobType`	published	Type of blob.
`Size`	published	Size of the blob field.

Methods

`FreeBuffers`	protected
`GetAsBytes`	protected
`GetAsString`	protected
`GetAsAnsiString`	protected
`GetAsUnicodeString`	protected
`GetAsVariant`	protected
`GetBlobSize`	protected
`GetIsNull`	protected
`GetText`	protected
`SetAsBytes`	protected
`SetAsString`	protected
`SetAsAnsiString`	protected
`SetAsUnicodeString`	protected
`SetVarValue`	protected
`Create`	public	Create a new instance of a TBlobField class.
`Clear`	public	Clear the BLOB field's contents.
`IsBlob`	public	Is the field a blob field.
`LoadFromFile`	public	Load the contents of the field from a file.
`LoadFromStream`	public	Load the field's contents from stream.
`SaveToFile`	public	Save field contents to a file.
`SaveToStream`	public	Save the field's contents to stream.
`SetFieldType`	public	Set field type.

Inherited

From TField (128)

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 CheckTypeSize ConstraintErrorMessage CurValue CustomConstraint DataChanged DataSet DataSize DataType DefaultExpression Destroy DisplayLabel DisplayName DisplayText DisplayWidth EditMask EditMaskPtr FieldDef FieldKind FieldName FieldNo FocusControl GetAsBCD GetAsBoolean GetAsCurrency GetAsDateTime GetAsExtended GetAsFloat GetAsInteger GetAsLargeInt GetAsLongint GetAsLongWord GetAsSingle GetAsUTF8String GetAsWideString GetCanModify GetClassDesc GetCurValue GetData GetDataSize GetDefaultWidth GetDisplayName GetNewValue GetOldValue GetParentComponent HasConstraints HasParent ImportedConstraint Index 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 SetAsBCD SetAsBoolean SetAsCurrency SetAsDateTime SetAsExtended SetAsFloat SetAsInteger SetAsLargeInt SetAsLongint SetAsLongWord SetAsSingle SetAsUTF8String SetAsVariant SetAsWideString SetData SetDataset SetDataType SetNewValue SetParentComponent SetParentField SetSize SetText Text Validate ValidChars 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.