Private Sub Command2_Click()
'连接数据库
If conn.State = 0 Then
   conn.ConnectionString = "Provider=Microsoft.jet.OLEDB.4.0;Data Source=" & _
 App.Path & "\设计计算.mdb;Persist Security Info=False"   '连接数据库的驱动字符串并打开数据库
   conn.Open
End If


'删除
Dim sql As String, r$
Set rs = New ADODB.Recordset     '创建数据集对象的连接

sql = "delete from [设计计算] where  [管段编号]=' " & MSHFlexGrid1.TextMatrix(MSHFlexGrid1.Row, 0) & " ' "     '删除指定行
conn.Execute sql   '执行sql语句
MSHFlexGrid1.RemoveItem MSHFlexGrid1.Row

rs.Open sql, conn, adOpenKeyset, adLockBatchOptimistic

MsgBox "删除成功！"

'删除数据库中该行记录
Dim a As String
a = MSHFlexGrid1.TextMatrix(MSHFlexGrid1.Row, 0)

'锁定到这条记录，然后查询并删除
txtSQL = "select * from [设计计算]  where [管段编号]= '" & a & "'"

Set rs = conn.ExecuteSQL(txtSQL, msgtext)     这行显示参数类型不匹配，或不在可以接受的范围内，或与其他参数冲突

conn.Close  '关闭连接
Set conn = Nothing   '释放变量

End Sub

Private Sub Command2_Click()
'连接数据库
If conn.State = 0 Then
   conn.ConnectionString = "Provider=Microsoft.jet.OLEDB.4.0;Data Source=" & _
 App.Path & "\设计计算.mdb;Persist Security Info=False"   '连接数据库的驱动字符串并打开数据库
   conn.Open
End If

'删除（有问题，按查询则删除的东西又回来了!）
Dim sql As String
Set rs = New ADODB.Recordset     '创建数据集对象的连接

Set rs.ActiveConnection = conn
sql = "delete from [设计计算] where  [管段编号]=' " & MSHFlexGrid1.TextMatrix(MSHFlexGrid1.Row, 0) & " ' "     '删除指定行
conn.Execute sql   '执行sql语句
MSHFlexGrid1.RemoveItem MSHFlexGrid1.Row
rs.Open sql, conn, adOpenKeyset, adLockBatchOptimistic
rs.Update
MSHFlexGrid1.Refresh
MsgBox "删除成功！"
conn.Close  '关闭连接
Set conn = Nothing   '释放变量
End Sub

是这样子么？可是还是在rs.update报错对象关闭时，不允许操作