TField

type TField = class(TComponent)

protected

  function AccessError();

  procedure CheckInactive;

protected

  class procedure CheckTypeSize(); virtual;

protected

  procedure Change; virtual;

  procedure DataChanged;

  procedure FreeBuffers; virtual;

  function GetAsBCD; virtual;

  function GetAsBoolean; virtual;

  function GetAsCurrency; virtual;

  function GetAsLargeInt; virtual;

  function GetAsDateTime; virtual;

  function GetAsFloat; virtual;

  function GetAsLongint; virtual;

  function GetAsInteger; virtual;

  function GetAsVariant; virtual;

  function GetOldValue; virtual;

  function GetAsString; virtual;

  function GetAsWideString; virtual;

  function GetCanModify; virtual;

  function GetClassDesc; virtual;

  function GetDataSize; virtual;

  function GetDefaultWidth; virtual;

  function GetDisplayName;

  function GetCurValue; virtual;

  function GetNewValue; virtual;

  function GetIsNull; virtual;

  function GetParentComponent; override;

  procedure GetText(); virtual;

  function HasParent; override;

  procedure Notification(); override;

  procedure PropertyChanged();

  procedure ReadState(); override;

  procedure SetAsBCD(); virtual;

  procedure SetAsBoolean(); virtual;

  procedure SetAsCurrency(); virtual;

  procedure SetAsDateTime(); virtual;

  procedure SetAsFloat(); virtual;

  procedure SetAsLongint(); virtual;

  procedure SetAsInteger(); virtual;

  procedure SetAsLargeint(); virtual;

  procedure SetAsVariant(); virtual;

  procedure SetAsString(); virtual;

  procedure SetAsWideString(); virtual;

  procedure SetDataset(); virtual;

  procedure SetDataType();

  procedure SetNewValue();

  procedure SetSize(); virtual;

  procedure SetParentComponent(); override;

  procedure SetText(); virtual;

  procedure SetVarValue(); virtual;

public

  constructor Create(); override;

Create a new TField instance

  destructor Destroy; override;

Destroy the TField instance

  procedure Assign(); override;

Copy properties from one TField instance to another

  procedure AssignValue();

Assign value of a variant record to the field.

  procedure Clear; virtual;

Clear the field contents.

  procedure FocusControl;

Set focus to the first control connected to this field.

  function GetData();

Get the data from this field

public

  class function IsBlob; virtual;

Is the field a BLOB field (untyped data of indeterminate size).

public

  function IsValidChar(); virtual;

Check whether a character is valid input for the field

  procedure RefreshLookupList;

Refresh the lookup list

  procedure SetData();

Save the field data

  procedure SetFieldType(); virtual;

Set the field data type

  procedure Validate();

Validate the data buffer

  property AsBCD: TBCD; [rw]

Access the field's contents as a BCD (Binary coded Decimal)

  property AsBoolean: Boolean; [rw]

Access the field's contents as a Boolean value.

  property AsCurrency: Currency; [rw]

Access the field's contents as a Currency value.

  property AsDateTime: TDateTime; [rw]

Access the field's contents as a TDateTime value.

  property AsFloat: Double; [rw]

Access the field's contents as a floating-point (Double) value.

  property AsLongint: LongInt; [rw]

Access the field's contents as a 32-bit signed integer (longint) value.

  property AsLargeInt: LargeInt; [rw]

Access the field's contents as a 64-bit signed integer (longint) value.

  property AsInteger: Integer; [rw]

Access the field's contents as a 32-bit signed integer (longint) value.

  property AsString: String; [rw]

Access the field's contents as an AnsiString value.

  property AsWideString: WideString; [rw]

Access the field's contents as a WideString value.

  property AsVariant: variant; [rw]

Access the field's contents as a Variant value.

  property AttributeSet: String; [rw]

  property Calculated: Boolean; [rw]

Is the field a calculated field ?

  property CanModify: Boolean; [r]

Can the field's contents be modified.

  property CurValue: Variant; [r]

Current value of the field

  property DataSet: TDataSet; [rw]

Dataset this field belongs to

  property DataSize: Integer; [r]

Size of the field's data

  property DataType: TFieldType; [r]

The data type of the field.

  property DisplayName: String; [r]

User-readable fieldname

  property DisplayText: String; [r]

Formatted field value

  property FieldNo: LongInt; [r]

Number of the field in the record

  property IsIndexField: Boolean; [r]

Is the field an indexed field ?

  property IsNull: Boolean; [r]

Is the field empty

  property Lookup: Boolean; [rw]

Is the field a lookup field

  property NewValue: Variant; [rw]

The new value of the field

  property Offset: Word; [r]

Offset of the field's value in the dataset buffer

  property Size: Integer; [rw]

Logical size of the field

  property Text: String; [rw]

Text representation of the field

  property ValidChars: TFieldChars; [r]

Characters that are valid input for the field's content

  property Value: variant; [rw]

Value of the field as a variant value

  property OldValue: variant; [r]

Old value of the field

  property LookupList: TLookupList; [r]

List of lookup values

published

  property Alignment: TAlignment; [rw]

Alignment for this field

  property CustomConstraint: String; [rw]

Custom constraint for the field's value

  property ConstraintErrorMessage: String; [rw]

Message to display if the CustomConstraint constraint is violated.

  property DefaultExpression: String; [rw]

Default value for the field

  property DisplayLabel: String; [rws]

Name of the field for display purposes

  property DisplayWidth: LongInt; [rw]

Width of the field in characters

  property FieldKind: TFieldKind; [rw]

The kind of field.

  property FieldName: String; [rw]

Name of the field

  property HasConstraints: Boolean; [r]

Does the field have any constraints defined

  property Index: LongInt; [rw]

Index of the field in the list of fields

  property ImportedConstraint: String; [rw]

Constraint for the field value on the level of the underlying database

  property KeyFields: String; [rw]

Key fields to use when looking up a field value.

  property LookupCache: Boolean; [rw]

Should lookup values be cached

  property LookupDataSet: TDataSet; [rw]

Dataset with lookup values

  property LookupKeyFields: String; [rw]

Names of fields on which to perform a locate

  property LookupResultField: String; [rw]

Name of field to use as lookup value

  property Origin: String; [rw]

Original fieldname of the field.

  property ProviderFlags: TProviderFlags; [rw]

Flags for provider or update support

  property ReadOnly: Boolean; [rw]

Is the field read-only

  property Required: Boolean; [rw]

Does the field require a value

  property Visible: Boolean; [rw]

Should the field be shown in grids

  property OnChange: TFieldNotifyEvent; [rw]

Event triggerd when the field's value has changed

  property OnGetText: TFieldGetTextEvent; [rw]

Event to format the field's content

  property OnSetText: TFieldSetTextEvent; [rw]

Event to set the field's content based on a user-formatted string

  property OnValidate: TFieldNotifyEvent; [rw]

Event to validate the value of a field before it is written to the data buffer

end;

TField

Provide access to the contents of a single field in a record

TComponent,IUnknown,IInterfaceComponentReference

TPersistent

TObject

TDataset

Base class for records-based data-access

TFieldDef

Class to describe one field in a record in a dataset

TFields

Collection of #fcl.db.TField instances