Setting Display and Edit Properties at Design Time

To edit the display properties of a selected field component, switch to the Properties page on the Object Inspector window. The following table summarizes display properties that can be edited.

Field component properties

Property	Purpose
Alignment	Left justifies, right justifies, or centers a field contents within a data-aware component.
ConstraintErrorMessage	Specifies the text to display when edits clash with a constraint condition.
CustomConstraint	Specifies a local constraint to apply to data during editing.
Currency	Numeric fields only. True: displays monetary values.False (default): does not display monetary values.
DisplayFormat	Specifies the format of data displayed in a data-aware component.
DisplayLabel	Specifies the column name for a field in a data-aware grid component.
DisplayWidth	Specifies the width, in characters, of a grid column that display this field.
EditFormat	Specifies the edit format of data in a data-aware component.
EditMask	Limits data-entry in an editable field to specified types and ranges of characters, and specifies any special, non-editable characters that appear within the field (hyphens, parentheses, and so on).
FieldKind	Specifies the type of field to create.
FieldName	Specifies the actual name of a column in the table from which the field derives its value and data type.
HasConstraints	Indicates whether there are constraint conditions imposed on a field.
ImportedConstraint	Specifies an SQL constraint imported from the Data Dictionary or an SQL server.
Index	Specifies the order of the field in a dataset.
LookupDataSet	Specifies the table used to look up field values when Lookup is True.
LookupKeyFields	Specifies the field(s) in the lookup dataset to match when doing a lookup.
LookupResultField	Specifies the field in the lookup dataset from which to copy values into this field.
MaxValue	Numeric fields only. Specifies the maximum value a user can enter for the field.
MinValue	Numeric fields only. Specifies the minimum value a user can enter for the field.
Name	Specifies the component name of the field component within Delphi.
Origin	Specifies the name of the field as it appears in the underlying database.
Precision	Numeric fields only. Specifies the number of significant digits.
ReadOnly	True: Displays field values in data-aware controls, but prevents editing. False (the default): Permits display and editing of field values.
Size	Specifies the maximum number of characters that can be displayed or entered in a string-based field, or the size, in bytes, of TBytesField and TVarBytesField fields.
Tag	Long integer bucket available for programmer use in every component as needed.
Transliterate	True (default): specifies that translation to and from the respective locales will occur as data is transferred between a dataset and a database. False: Locale translation does not occur.
Visible	True (the default): Permits display of field in a data-aware grid.False: Prevents display of field in a data-aware grid component.User-defined components can make display decisions based on this property.

Not all properties are available for all field components. For example, a field component of type TStringField does not have Currency, MaxValue, or DisplayFormat properties, and a component of type TFloatField does not have a Size property.

While the purpose of most properties is straightforward, some properties, such as Calculated, require additional programming steps to be useful. Others, such as DisplayFormat, EditFormat, and EditMask, are interrelated; their settings must be coordinated. For more information about using DisplayFormat, EditFormat, and EditMask, see Controlling and masking user input.

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