A quick and simple Velocimacro to generate HTML Select boxes and its Options; automatically selects the correct option based on the value given.

You can place this #macro anywhere in your Velocity templates but I used my global VM_global_library.vm file.

Code

Example Usage

The resulting HTML:

Addendum

11th November 2005 : Thanks to MATT for pointing out the FreeMarker template engine as a promising replacement for Velocity.

Problem

I discovered that comparisons in Velocity if statements are type-sensitive the hard way.

For example, I am trying to display the 'selected' option in a html <SELECT> object. The list of possible values is $list, each is a simple 'NameValuePair' value object { String name, String value }.

The object I am editing in this form is $obj, and the field I am testing against is $obj.typeId defined as a long.

However, the if statement on line 3 is actually comparing a String to a long which are of course never going to be equal.

Solution

The easiest work around in this case was to convert the $obj.typeId into a String before the comparison.

Any comments / feedback welcomed

If you're reading this article you've probably encounted the same problem as I have. I was trying to put a newline '\n' character in the value of a variable in a Velocity template.

Attempt 1:

I assumed \n would work...

This produced There was no foo set in the Context.\nPlease do something about it. as the value of $foo.

Attempt 2:

I just thought this was worth a shot

And the template failed to compile

Solution:

Basically, the easiest way I found is to place the newline, carriage return or other special character in the context.

And in your template:

Maybe not the best solution but it works for me. If you expect to use it across your entire application I suggest you override VelocityServlet.createContext in your Servlet to add these characters to every context in your application.

Example: