excel - VBA check if file exists -

i have code. supposed check if file exists , open if does. work if file exists, , if doesn't, however, whenever leave textbox blank , click submit button, fails. want, if textbox blank display error message if file didn't exist.

runtime-error "1004"

dim file string file = textbox1.value dim dirfile string  dirfile = "c:\documents , settings\administrator\desktop\" & file if dir(dirfile) = ""   msgbox "file not exist" else     workbooks.open filename:=dirfile end if 

something this

best use workbook variable provide further control (if needed) of opened workbook

updated test file name actual workbook - makes initial check redundant, other message user textbox blank

dim strfile string dim wb workbook strfile = trim(textbox1.value) dim dirfile string if len(strfile) = 0 exit sub  dirfile = "c:\documents , settings\administrator\desktop\" & strfile if len(dir(dirfile)) = 0   msgbox "file not exist" else  on error resume next  set wb = workbooks.open(dirfile)  on error goto 0  if wb nothing msgbox dirfile & " invalid", vbcritical end if