In general, you can use variants to store any data type and perform numerous operations and type conversions. The Variant type, in fact, has a pervasive effect on the whole language, and the Delphi components library also uses them in ways not related to OLE programming. Here I want to discuss this data type from a general perspective. To provide full OLE support, the 32-bit version of Delphi includes the Variant data type. The cover of the 4th edition of Essential Pascal, Not the answer youre looking for Browse other questions tagged delphi or ask your own question.Essential Pascal on Marco Web Center Provide details and share your research But avoid Asking for help, clarification, or responding to other answers. Note, however, that a user can paste non-numeric characters in the textfield even when this property is set.Īn EditMask property using following characters can produce a valid numeric input, including negative values. To accommodate this, I add a KeyPress event that checks that the field is valid (not just for numbers), change the background colour to yellow if it isnt and disable any buttons that require this field to be valid.Īdditionally sometimes I add a message (e.g. Instead they want some feedback that the input in a field is invalid. If youre using an earlier version, read about Edit masks in the OLH. If the decimal separator is left blank then the current regional setup value is used. The format string is an argument for the Delphi Format function, which FastReport uses to implement number formatting. Well select the Number category and 1,234.50 format. To apply formatting to the SUM result, lets use the value formatting tools in FastReport. You can customize the fields as necessary, to implement a rating image for instance (a control that shows a different image based on a numeric value). This package defines the classes that implement a custom appearance for list view items.
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