如何捕获oledbdatareader错误

Question

我有这个代码，我写的是为了找出数据库中是否存在记录。当找到记录时，它工作得很好。如果不是，就会出现一个错误。我希望在消息框中捕获错误，该消息框声明“未找到记录”。

         Dim findprinc As String = TextBox1.Text.Substring(0, 16)
        MsgBox(findprinc)
        sql = "Select RealID from Dets where ID like '%" & findprinc &                "%'"
        MsgBox(sql)
        Dim conn As New OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0; Persist Security Info=false; Data Source=..\new.mdb")
        conn.Open()
        Dim cmd As New OleDbCommand(sql, conn)
        Dim numeri As OleDbDataReader = cmd.ExecuteReader
        numeri.Read()

Answer 1

 Dim findprinc As String = TextBox1.Text.Substring(0, 16)
    MsgBox(findprinc)
    Sql = "Select RealID from Dets where ID like '%" & findprinc & "%'"
    MsgBox(Sql)
    Dim conn As New OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0; Persist Security Info=false; Data Source=..\new.mdb")
    conn.Open()
    Dim cmd As New OleDbCommand(Sql, conn)
    Dim numeri As OleDbDataReader = cmd.ExecuteReader
    Dim recordFound As Boolean = False
    While numeri.Read
        recordFound = True
    End While
    If recordFound = False Then
        MsgBox("Record Not Found")
    End If