Private Sub Form_Load()
    rs1.Open "select * from 操作员", cnn, adOpenKeyset, adLockOptimistic
    For i = 1 To rs1.RecordCount
        txtUserName.AddItem (rs1.Fields("姓名"))
        rs1.MoveNext
    Next i
    rs1.Close

    Dim sBuffer As String
    Dim lSize As Long


    sBuffer = Space$(255)
    lSize = Len(sBuffer)
    Call GetUserName(sBuffer, lSize) '````
    If lSize > 0 Then
        txtUserName.Text = Left$(sBuffer, lSize)
    Else
        txtUserName.Text = vbNullString
    End If
End Sub


谢谢各位高手的指点！！