Attributes.Add("class", "className") but preserve existing class

Question

Simple thing, well, I think it is.

I need to Add a class to an element within an asp:repeater under certain conditions, using VB.

So, I can do

ITEMID.Attributes.Add("class", "classToAdd")

But this removes the existing classes and therefore screws up my CSS.

ITEMID.Attributes("class") = "classToAdd"

Seems to do the same thing.

How do I add a class to an element, whilst preserving it's existing class values?

Answer 1

Use += to add additional class, and make sure you leave a space before or else it will appear as currentClassclassToAdd, where current class is currentClass:

ITEMID.Attributes("class") += " classToAdd"

---

This is the same as doing:

ITEMID.Attributes("class") = ITEMID.Attributes("class") + " classToAdd"

Therefore:

ITEMID.Attributes("class") = "currentClass" + " classToAdd"

Answer 2

You need to stack them up:

Dim existingClasses as string = ITEMID.Attributes("class")

ITEMID.Attributes.Add("class", existingClasses & " classToAdd")