如何使用依赖于ASP.NET中的互相多个数据源？ [英] How to use multiple datasources that rely on each other in ASP.NET?

问题描述

我正在用2下拉列表一个网站，一个是连接到显示所有产品的名称的数据源，第二个显示所有客户（罗斯文）的公司名称。

I'm making a website with 2 dropdown lists, one is connected to a datasource that displays the names of all products, the second displays the company name of all customers (northwind).

之后，一个按钮被击中如果从客户（dropdownlist2）的订单，其显示的GridView，显示订单id，订购日期，SHIPDATE和数量，他们订购该产品（dropdownlist1），否则我将有一个验证器设置，如果这种情况并没有发生。

After both options are selected, a button is hit which displays a gridview that shows the orderid, orderdate, shipdate, and quantity if there is an order from that customer (dropdownlist2) where they ordered that product (dropdownlist1), otherwise I'll have a validator set up if that scenario hasn't happened.

我不明白的是如何取得第三个数据源的SQL是动态的，因为它需要使用什么在2下拉列表的条件。到目前为止，这是我有：

Protected Sub Button1_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles Button1.Click
    GridView1.Visible = True

    Dim v1, v2 As String
    v1 = DropDownList1.SelectedItem.Value.ToString
    v2 = DropDownList2.SelectedItem.Value.ToString

    SqlDataSource3.SelectCommand = "select O.OrderID, OrderDate, ShippedDate, Quantity" _
                                 & "from Orders O, [Order Details] D, Customers C, Products P" _
                                 & "where O.OrderID = D.OrderID" _
                                 & "and C.CustomerID = O.CustomerID" _
                                 & "and P.ProductID = D.ProductID" _
                                 & "and companyname = '" & v1 & "'" _
                                 & "and productname = '" & v2 & "'"

End Sub

---

很抱歉，如果我要这一切错了，这是一个使用计算器我第一次

---

Sorry if I'm going about all this wrong, this is my first time using StackOverflow

推荐答案

按照这个例子中，假设 ddlTwo 取决于 ddlOne 和GridView GV 取决于选择两个DropDownLists的：

Follow this example, assuming that ddlTwo is dependant on ddlOne and GridView gv is dependant on selection of both DropDownLists:

Protected Sub Page_Init(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Init
    If Not IsPostBack Then
        ddlOne.DataBind()
        ddlTwo.DataBind()
    End If
End Sub

Protected Sub ddlOne_DataBinding(sender As Object, e As EventArgs) Handles ddlOne.DataBinding
    sender.DataSource = someListOne
    sender.DataTextField = "TXT"
    sender.DataValueField = "ID"
End Sub

Protected Sub ddlTwo_DataBinding(sender As Object, e As EventArgs) Handles ddlTwo.DataBinding
    sender.DataSource = someListTwo
    sender.DataTextField = "TXT"
    sender.DataValueField = "ID"
End Sub

Protected Sub ddlOne_SelectedIndexChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles ddlOne.SelectedIndexChanged
    ddlTwo.DataBind()
    gv.DataBind()
End Sub

Protected Sub ddlTwo_SelectedIndexChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles ddlTwo.SelectedIndexChanged
    gv.DataBind()
End Sub

Protected Sub gv_DataBinding(sender As Object, e As EventArgs) Handles gv.DataBinding
    sender.DataKeyNames = {"ID"}
    sender.DataSource = GetDataSource(ddlOne.SelectedValue, ddlTwo.SelectedValue)
End Sub

此外，作为user2615302提到的，设置的AutoPostBack选项设置为True

Also, as user2615302 mentioned, set the AutoPostBack option to True

这篇关于如何使用依赖于ASP.NET中的互相多个数据源？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！