SqlDataReader 收集一行值而不是所有行？SqlDataReader 的困惑和新手

Question

两个表：

购物车(CARTID，用户ID，DateCreated，ProductID，productName，sige，价格，价格，数量，数量，小计，工作时间(

(

products (productid，name，sdescription，价格，大小，图像，缩略图，重量，ldescription，ldescription，cott，cattoryId，hourswork(

>

我要做的事情：根据SELECT语句选择的类别的所有显示两个按钮之一。

类别ID范围为1-7。如果选定的任何类别匹配" 1" 2"或" 7"，则应显示'创建预订'按钮，否则应显示'交货选项'按钮。

Protected Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs)
       'Display the correct button:
    Dim conn As SqlConnection = New SqlConnection(ConnectionString)
    Dim cmd As SqlCommand = New SqlCommand
    cmd.CommandText = "SELECT products.CategoryID FROM Products INNER JOIN Cart on products.ProductID = cart.ProductID WHERE ([UserID] = @UserID) AND ([DateCreated] = CONVERT(date, GETDATE()))"
    Dim UserID As SqlParameter = New SqlParameter("@UserID", SqlDbType.NVarChar, 128)
    UserID.Value = "249f38b8-e745-44f4-8d78-806b0e5e7e0e"
    cmd.Parameters.Add(UserID)
    cmd.Connection = conn
    conn.Open()
    cmd.ExecuteNonQuery()
    Dim reader As SqlDataReader = cmd.ExecuteReader
    Dim CategoryID As Integer
    While reader.Read()
         'CategoryID = reader.GetValue(0)
    CategoryID = CType(reader("CategoryID"), Integer)
    End While
    conn.Close()
    lblTest.Text = CategoryID
    If CategoryID = "1" Or "2" Or "7" Then
            btnCreateBooking.Visible = True
        Else
            btnDeliveryOptions.Visible = True
        End If
End Sub

但是，sqldatareader在标签/变量中生产的 last 产品的类别ID是唯一的，。

Answer 1

在此处找到答案：https：//forums.asp.net/t/1401666.aspx?c datareader returning multiple mmultiple mmultiple ass ass ass ass ass label quequestion quequestion quequest/p>

If reader.HasRows Then
        While reader.Read()
            lblTest.Text = (lblTest.Text _
                + (reader("CategoryID").ToString + "<br>"))
        End While
        conn.Close()
    End If 

并将我的if语句更正为：

If lblTest.Text.Contains("1") Or lblTest.Text.Contains("2") Or lblTest.Text.Contains("7") Then
        btnCreateBooking.Visible = True
    Else
        btnDeliveryOptions.Visible = True
        End If