Is wicket:label needed with wicket:for?

Question

In the past I have built labels for my form like this:

<label wicket:for="name"><wicket:label><wicket:message key="name"></wicket:message></wicket:label>:</label><input wicket:id="name" type="text"/>

Do I still need to use the wicket:label tag? I am not using wicket:label in wicket 7 and it seems to work fine. I may not be understanding the purpose of using wicket:label. It seems like wicket:label is just additional markup. Below is what I am doing now. Is this correct?:

<label wicket:for="name"><wicket:message key="name"></wicket:message>:</label><input wicket:id="name" type="text"/>

This example is related to Wicket XHTML tags

Answer 1

Have a look at the JavaDoc of AutoLabelResolver and AutoLabelTextResolver.

The <label wicket:for="name"> is handled by AutoLabelResolver. It links the HTML label tag to the HTML form component (in your case the input tag) by filling in the correct ID in the HTML for attribute of the label. It also adds css classes to the label tag for for example errors, so you can style the text in the label tag in case of an error.

The <wicket:label> has two purposes. If you give it a value either by the key attribute (as you did) or by having some text between the tags, the text is set as the label model of the Java FormComponent, which then is used in validation messages like this '${label}' is required. (see LabeledWebMarkupContainer#setLabel and LabeledWebMarkupContainer#getLabel).

If you don't assign any text to the <wicket:label> tag, then it is used as output. That means the value of the label model of your Java FormComponent is used to replace the tag.

If you have no <wicket:label> in the HTML markup and no label model set in your Java code, then your Java FormComponent will have an empty label model and Wicket falls back to using the Wicket ID as label. So depending on how your Wicket IDs look, you will get validator messages like 'user_name' is required. instead of something nice looking like 'User name' is required.