Question

我想从sql数据库中搜索一个记录的名字，所以我在数据层中使用了一个函数，但它无法正常工作请纠正我的错误，这里是我的功能：

Public Function searchCustomer(ByVal custFname As String) As DataTable
            Dim tabletdata As New DataTable
            Dim conn As New SqlConnection(con_string)
            conn.Open()
            Dim dCmd As New SqlCommand("selectCustomerByFname", conn)
            dCmd.CommandType = CommandType.StoredProcedure
            Try
                dCmd.Parameters.AddWithValue("@Cust_Fnam", custFname)
                'dCmd.ExecuteNonQuery()
                Dim dadaptr As New SqlDataAdapter(dCmd)
                dadaptr.SelectCommand = dCmd
                dadaptr.SelectCommand.ExecuteNonQuery()
                dadaptr.Fill(tabletdata)


                Return tabletdata
            Catch
                Throw
            Finally
                dCmd.Dispose()
                conn.Close()
                conn.Dispose()
            End Try

        End Function

Answer 1

填充方法隐式打开和关闭连接。 Fill Method

摘要：Fill方法检索来自数据源的行使用由一个指定的SELECT语句关联的SelectCommand属性。该与之关联的连接对象 SELECT语句必须有效，但它不需要打开。如果连接在Fill之前关闭调用，它被打开以检索数据，然后关闭如果连接已打开在调用Fill之前，它仍然存在开。

Public Function searchCustomer(ByVal custFname As String) As DataTable
  Dim tabletdata As New DataTable
  Dim conn As New SqlConnection(con_string)
  Dim dCmd As New SqlCommand("selectCustomerByFname", conn)
  dCmd.CommandType = CommandType.StoredProcedure

  dCmd.Parameters.AddWithValue("@Cust_Fnam", custFname)
  Dim dadaptr As New SqlDataAdapter(dCmd)
  dadaptr.SelectCommand = dCmd
  dadaptr.Fill(tabletdata)
  Return tabletdata
End Function

数据库搜索功能

1 个答案: