# Entering NULL and Empty Values

Learn about entering NULL and empty values in C1Input.

## Content



Unless in edit mask mode or in date-time editing with [DateTimeInput](/componentone/api/win/online-input/dotnet-framework-api/C1.Win.C1Input.4.8/C1.Win.C1Input.C1TextBox.DateTimeInput.html) set to **True**, the user can enter a null value in one of the following ways:

*   If the control text equals [NullText](/componentone/api/win/online-input/dotnet-framework-api/C1.Win.C1Input.4.8/C1.Win.C1Input.C1TextBox.NullText.html), the resulting value is null. The effective NullText value here is determined by NullText. Comparison with NullText is case-sensitive or not depending on the **CaseSensitive** property.
*   Clearing the control, entering an empty string results in null value if the C1TextBox.EmptyAsNull property is set to True (it is False by default).
*   In programmatic parsing, DBNull value can be returned by the programmer in the **Parsing** event.

If the user enters a null value (either by entering an empty string or NullText, see above), input string validation and parsing are skipped, see [Input string validation (PreValidation)](/componentone/docs/win/online-input/usingthec1inputcontr/validatingdata/inputstringvalidatio) and [Parsing (Updating) Data](/componentone/docs/win/online-input/usingthec1inputcontr/parsingupdatingdata). However, [PostValidation](/componentone/api/win/online-input/dotnet-framework-api/C1.Win.C1Input.4.8/C1.Win.C1Input.C1TextBox.PostValidation.html) is performed in this case as in all others, see [Typed value validation (PostValidation)](/componentone/docs/win/online-input/usingthec1inputcontr/validatingdata/typedvaluevalidation).

## See Also

[Customizing C1Input's Appearance](/componentone/docs/win/online-input/customizingc1inputsa)