You could use substring, this will split the string or aka your textbox.
This takes two params, The starting index of the string and the 2nd param is the length. I have put str.indexof in the 2nd param to get the index of where the space is.
dim str as string
Label1.Text = str.Substring(0, str.IndexOf(" "))
This code is not tested, I only used visual basic for a little bit when i was 12.