I often hear in English conversation or movies the contraction "ain't" (for "isn't"), but I am more surprised to see it in writing (and I am not referring to a novel, where I can understand its usage: convey common oral expressions in a text)
See this question (on a technical forum) for instance:
"There ain’t ListBox.SelectionMode=“None”, is there another way to disable selection in a listbox?"
Is it appropriate in that context (formal written technical question)?