How to validate input dialog?

caUserInput = inputdlg(Prompts, titleBar, 1);
if length(caUserInput) > 10
 f = warndlg('Exceed numbers','Warning');
   return
end

I insert some values from the input dialog,Then i need to check the length of the value is exced the 10,

How can i do it?

I try it in this way,But it dosent work.