TField.IsValidChar Method

Indicates whether a particular character is valid for the field.

Pascal

function IsValidChar(InputChar: Char): Boolean; virtual;

C++

virtual __fastcall Boolean IsValidChar(Char InputChar);

Description

Call IsValidChar to determine if the character specified by InputChar can appear in the text representation of the field's value. Many data-aware controls use IsValidChar to check characters entered by the user to determine if they are valid. IsValidChar returns true if InputChar can appear in the field. IsValidChar returns false if InputChar is not a valid character for the field type.

The valid characters for a field object are given by the ValidChars property. By default, field objects accept all characters as valid. For each DataType that restricts the set of valid characters, the default valid characters are listed below:

DataType	Valid characters
ftSmallint	Digits 0 to 9, plus sign (+), and minus sign (-).
ftWord	Digits 0 to 9, plus sign (+), and minus sign (-)
ftAutoInc	Digits 0 to 9, plus sign (+), and minus sign (-)
ftInteger	Digits 0 to 9, plus sign (+), and minus sign (-)
ftLargeInt	Digits 0 to 9, plus sign (+), and minus sign (-)
ftCurrency	Digits 0 to 9, plus sign (+), minus sign (-), the letter E (E or e) and the decimal separator from the regional settings in the Windows control panel.
ftFloat	Digits 0 to 9, plus sign (+), minus sign (-), the letter E (E or e) and the decimal separator from the regional settings in the Windows control panel
ftBCD	Digits 0 to 9, plus sign (+), minus sign (-), and the decimal separator from the regional settings in the Windows control panel.

Note: For some datatypes, such as ftGraphic, IsValidChar returns true for all characters although not every character is valid for the field. IsValidChar provides only a rough validation of input characters. More refined character-by-character validation can be provided by an edit mask. Also, the value for a field is validated as a whole when it is written to the database record.