Dune5 DateTime Picker Web Control V1.2 Documentation Contents

DateTimePicker.IsNull Property

Notes

Gets a System.Boolean value indicating whether the user has selected nothing.

This property returns TRUE only if AllowNullValue is TRUE and the user has not selected any Year/Month/Day/etc values.

Use IsNull to decide whether the user has not entered a datetime, as opposed to entering an erroneous datetime.

Example User Input	State of Control after Postback	Example Application
Reminder Date : ,	IsNull would return TRUE, and HasValue would return FALSE.	The user does not want a reminder. Update the datetime reminder column for this record as NULL in the database.
Reminder Date : ,	IsNull would return FALSE and HasValue would return FALSE.	The user does want a reminder but hasn't specified a valid value ( HasValue = FALSE ). Display a validation message and ask the user to enter a valid date, or none at all.
Reminder Date : ,	IsNull would return FALSE and HasValue would return TRUE.	The user does want a reminder and has specified a valid value. Update the database, set IsEditable to FALSE and display the web form in a confirmation mode.

[Visual Basic]
Overridable Public Readonly Property IsNull As Boolean

[C#]
public virtual bool IsNull {get;}

[C++]
public: __property virtual bool get_IsNull();

[JScript]
public function get IsNull() : bool;