下面代码怎么不能实现删除选中的项？
cmd.executenonquery()语句出错，提示如下：
未处理的“System.Data.OleDb.OleDbException”类型的异常出现在 system.data.dll 中。


Dim dad As New OleDb.OleDbDataAdapter
Dim ds As New System.Data.DataSet
Dim cmd As New OleDbCommand
Dim str As String = "delete from title where pernodes='" & ComboBox1.Text & "' and chinodes='" & ComboBox1.Text & "'"
cmd.Connection = OleDbConnection1
cmd.CommandType = CommandType.Text
cmd.CommandText = str
OleDbConnection1.Open()
cmd.ExecuteNonQuery()

OleDbConnection1.Close()

检查一下OleDbConnection1的连接字符串

哪里错我就不知道了
Try
'将可能出错的语句加入这里
Catch ex As Exception
'这样错误会更明确
MsgBox(ex.Message)
End Try
///////////////点解不将语句///////////////////
Dim str As String
str = "delete from title where pernodes='" & ComboBox1.Text & "' and chinodes='" & ComboBox1.Text & "'"
/////////////改成这样,这样会方便点///////////
Dim str As String
str = String.Format("delete from title where pernodes='{0}' and chinodes='{1}'", ComboBox1.Text,ComboBox1.Text)