Use the below code:
Code:
Private Sub cmdLoad_Click()
Dim F
Dim Temp As String
F = FreeFile
Open "c:\file1.dat" For Input As #F
Do While Not EOF(F)
    Input #F, Temp
    List1.AddItem Temp
Loop
Close #F
MsgBox "Loaded"
End Sub

Private Sub cmdSave_Click()
Dim F
F = FreeFile
Open "c:\file1.dat" For Output As #F
For i = 0 To List1.ListCount
    Print #F, Str(List1.List(i))
Next i
Close #F
MsgBox "Saved"
End Sub