类型：转载 责任编辑：asp.net 日期：2007/05/23
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帮我写了一个函数 用来检查表中是否存在某条记录
存在返回真,不存在假.
我写的老是提示什么类型 DBNull 无法转换 到 integer
哪里错了，
Public Function Exist(ByVal strSql As String) As Boolean
//注: strsql="select * from customers where id=00001"
Dim myCmd As New OleDbCommand
Try
myCmd.CommandText = strSql
myCmd.Connection = cn
myCmd.CommandType = CommandType.Text
If myCmd.ExecuteNonQuery Then
Return True
Else
Return False
End If
Catch ex As Exception
MsgBox(ex.ToString)
Finally
myCmd.dispose()
End Try
End Function
网友回答：
Public Function Exist(ByVal strSql As String) As Boolean
strsql="select count(id) from customers where id=00001"
Dim myCmd As New OleDbCommand
Try
myCmd.CommandText = strSql
myCmd.Connection = cn
myCmd.CommandType = CommandType.Text
dim intC as integer=Convert.ToInt32(objCmd.ExecuteScalar())
If intC=0 Then
Return false
Else
Return true
End If
Catch ex As Exception
MsgBox(ex.ToString)
Finally
myCmd.dispose()
End Try
End Function