SqlException捕获错误 [英] SqlException caught error

问题描述

请问我正在设计用于学习目的的演示航空公司网站上是否有错误.该错误必须声明标量变量"@Dep"
下面是我的代码，用于使用用户选择的值来显示数据库的结果.被抓到

Please i am having an error from my demo airline website i am designing for learning purpose.The error is must declare the scalar variable "@Dep"
Below is my code to use user selected values to display result from a database. was caught

Protected Sub buttFindFlight_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles buttFindFlight.Click
        Try

            Dim conn As New SqlConnection
            Dim cmd As New SqlCommand
            Dim adp As New SqlDataAdapter
            Dim ds As New DataSet
            conn.ConnectionString = ConfigurationManager.ConnectionStrings("AirportReservationSystemConnectionString").ConnectionString
            cmd.Connection = conn
            conn.Open()
            ''cmd.CommandType = CommandType.Text


            adp = New SqlDataAdapter("select LeavPlace as Departing, DestPlace As Destination FROM  DailyFlightInfo where LeavPlace =@Dep And DestPlace =@Dest ", conn)

            cmd.Parameters.Add(New SqlParameter("@Dep", SqlDbType.VarChar, 50))
            cmd.Parameters.Add(New SqlParameter("@Dest", SqlDbType.VarChar, 50))

            cmd.Parameters("@Dep").Value = drpLeaving.SelectedItem.Value
            cmd.Parameters("@Dest").Value = drpGoing.SelectedItem.Value

            adp.Fill(ds)
            gridView.DataSource = ds
            gridView.DataBind()

推荐答案

@Dep 代表什么?
您是否要使用参数化查询.
如果是这样，请使用sqlcommand而不是SqlDataAdapter.这是一个示例 [

What does @Dep stands for?
Are you trying to use parameterized query.
If so, use sqlcommand instead of SqlDataAdapter. Here is an Example[^]

Regards
Sebastian

我找不到您的命令和dataAdapter之间的连接，因此请尝试以下操作:

I can''t find connection between your command and dataAdapter therefore try this:

'...

cmd.CommandText = "select LeavPlace as Departing, DestPlace As Destination FROM  DailyFlightInfo where LeavPlace =@Dep And DestPlace =@Dest "

cmd.Parameters.Add(New SqlParameter("@Dep", SqlDbType.VarChar, 50))
cmd.Parameters.Add(New SqlParameter("@Dest", SqlDbType.VarChar, 50))
cmd.Parameters("@Dep").Value = drpLeaving.SelectedItem.Value
cmd.Parameters("@Dest").Value = drpGoing.SelectedItem.Value

adp = New SqlDataAdapter(cmd);

adp.Fill(ds)
gridView.DataSource = ds
gridView.DataBind()

'...

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