VB用mschart画折线图，怎样做到变换坐标？

我想变换坐标，比如说新增加一个缩短按钮，点击按钮，横坐标就会变短。

这是我的代码：
请大家帮忙
Option Explicit


Private Sub cmd_close_Click()
    Unload Me
End Sub

Private Sub cmd_pic_Click()
    Dim s As String, i As Long, ss() As String
    Dim cn As New adodb.Connection
    Dim rs As New adodb.Recordset
    cn.CursorLocation = adUseClient
 
    cn.Open "Provider=SQLOLEDB.1;Integrated Security=SSPI;Persist Security Info=False;Initial Catalog=sample;Data Source=."
    rs.Open "select number,sdatetime,data from udata", cn, adOpenStatic, adLockOptimistic
 
    If rs.RecordCount = 0 Then Exit Sub
    ReDim ss(rs.RecordCount)
    With MSChart1
      .RowCount = rs.RecordCount
      .ColumnCount = 1
 
      .chartType = VtChChartType2dLine
      For i = 1 To rs.RecordCount
        .Row = i
        .Data = rs.Fields("data")         
        .RowLabel = rs.Fields("sdatetime")
        rs.MoveNext
      Next i
  &nb