Generate random Code consist of number and letter using VBA code

Dear All
i would like to use VBA code in excel to generate random Alphanumric in range of cell for example A1:A19
or for another case
A1 : C12

i search on internet and found code but it work with access and find its very useful to use it
as the following

HTML Code: 

i will be thankful if we can create something like this in userform in excel that enable select width of random needed like in attached photo but instead to result will put range of cell needed