As per the JavaDoc: AbstractSingleSelectChoice<T> org.apache.wicket.markup.html.form.AbstractSingleSelectChoice.setNullValid(b oolean nullValid)
Determines whether or not the null value should be included in the list of choices when the field's model value is nonnull, and whether or not the null_valid string property (e.g. "Choose One") should be displayed until a nonnull value is selected. If set to false, then "Choose One" will be displayed when the value is null. After a value is selected, and that change is propagated to the underlying model, the user will no longer see the "Choose One" option, and there will be no way to reselect null as the value. If set to true, the null string property (the empty string, by default) will always be displayed as an option, whether or not a nonnull value has ever been selected. Note that this setting has no effect on validation; in order to guarantee that a value will be specified on form validation, setRequired(boolean). This is because even if setNullValid() is called with false, the user can fail to provide a value simply by never activating (i.e. clicking on) the component. If I'm not mistaken your code should looks something like this: // Instruct Wicket to always display the null value in your select dropDownChoice.setNullValid(true); // We want the user to select null so this is no longer a required field dropDownChoice.setRequired(false); If you want to change the label this null is mapped to from "Choose One" to something else: dropDownChoice = new DropDownChoice<M>(LabeledFormField.FIELD_ID, model, choices) { @Override protected String getNullValidKey() { return "Your.Own.Language.Pack.Key"; } }; ~ Thank you, Paul Bors -----Original Message----- From: eugenebalt [mailto:eugeneb...@yahoo.com] Sent: Friday, June 21, 2013 11:09 AM To: users@wicket.apache.org Subject: Set the Null option manually in a NullValid Dropdown We have a dropdown which supports the NullValid property. If we need to set its selection to Null manually, setModel(null) does not seem to work. Should we set it to the first element of the backing model (which is an KeyValueBean list)? -- View this message in context: http://apache-wicket.1842946.n4.nabble.com/Set-the-Null-option-manually-in-a -NullValid-Dropdown-tp4659670.html Sent from the Users forum mailing list archive at Nabble.com. --------------------------------------------------------------------- To unsubscribe, e-mail: users-unsubscr...@wicket.apache.org For additional commands, e-mail: users-h...@wicket.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: users-unsubscr...@wicket.apache.org For additional commands, e-mail: users-h...@wicket.apache.org