为什么我的datagrid不能显示数据呢？

[tonyathome]

'自定义函数
Private Function ShowDetails(systemno) As Boolean
Dim con As New ADODB.Connection
Dim rst As New ADODB.Recordset
Dim sqlstr As String
Dim constr As String

'建立数据库文件的相对路径
constr = App.Path
If Right(constr, 1) <> "\" Then
constr = constr + "\"
End If
constr = "Provider=Microsoft.Jet.OLEDB.4.0;Persist Security Info=False;Data Source=" & constr & "InvoicePrint.mdb"
'打开数据库连接
con.Open constr
'建立查询字符串
sqlstr = "select * from Details where system_no='" & systemno & "'"
'打开数据记录集
rst.Open sqlstr, con, adOpenStatic
If rst.EOF Then
MsgBox "No Details info!"
Else
Set dgrDetails.DataSource = rst
dgrDetails.Visible = True

End If
'关闭数据记录集
rst.Close
'关闭数据库连接
con.Close
End Function