如何检查oledbcommand是否成功？

Question

我正在访问数据库，我想知道如何修复下面的代码，以便我可以向用户显示正确的信息。问题是，如果oledb命令没有成功，我想显示一条错误消息。

 Try 

     cn = New OleDbConnection(" Provider=Microsoft.Jet.OLEDB.4.0;Data Source=F:\ro.mdb") 
     'provider to be used when working with access database 
     cn.Open() 
     cmd = New OleDbCommand("select * from [Table1]", cn) 

     cmd.CommandText = "insert into [Table1]([LNAME], [FNAME], [MNAME], [POS], [UNAME], [PASS]) values('" + lstname + "','" + frsname + "','" + midname + "','" + post + "','" + usrname + "','" + pword + "')" 


     cmd.ExecuteNonQuery() 

    Catch 
     MsgBox("Either one of the text box is empty or the IDNUMBER entered is already on the database", MsgBoxStyle.Critical) 


    End Try 

Answer 1

这开始作为一个SQLEXCEPTION并改为OLEDB这个问题。对不起，没有测试。

Try  
     ... 
    Catch dbException as OledbException 
     Dim myErrors as OledbErrorCollection = dbException.Errors 
     Dim i as Integer 
      For i = 0 to myErrors.Count - 1 
       MessageBox.Show("Index #" & i & ControlChars.Cr & _ 
        "Error: " & myErrors(i).ToString() & ControlChars.Cr) 
      Next i 
    Finially 
     ... 

Answer 2

弄清楚你想要什么例外陷阱，并抓住他们明确

Try 

Catch se As SpecialException 
    MsgBox("Error1") 

Catch e As Exception ' Catch all other exceptions. 
    MsgBox("General Error") 

End Try