Open the file and use Line Input to read it one line at a time, adding each line to the ListBox.
Private Sub cmdLoad_Click()
Dim fnum As Integer
Dim file_line As String
lstLines.Clear
fnum = FreeFile
Open txtFile.Text For Input As fnum
Do While Not EOF(fnum)
Line Input #fnum, file_line
lstLines.AddItem file_line
Loop
End Sub
