关于datagrid显示的一个小问题

Set rst3 = New ADODB.Recordset
If cnn1.State = adStateOpen Then cnn1.Close
If rst3.State = 1 Then rst3.Close
cnn1.Open cnnstr
cnn1.CursorLocation = adUseClient
sqlstr = "select * from ct"
rst3.Open sqlstr, cnn1, adOpenKeyset, adLockOptimistic, adCmdText
Set DataGrid1.DataSource = rst3
DataGrid1.Refresh有几条记录，就显示几行空白行，没有内容，不知道为什么