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departmentList
True
departmentDS
。
courseGridView
。
departmentDS
EntityDataSource 控件,单击其智能标记并选择“配置数据源”命令。
departmentList
DropDownList 控件,单击智能标记,然后单击“选择数据源”。
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schoolContext
属性。
departmentList
DropDownList 控件。
departmentList
控件的 SelectedIndexChanged 事件处理程序。
// Get the department ID.Int32 departmentID = Convert.ToInt32(departmentList.SelectedValue);// Select course information based on department ID.var courseInfo = from c in schoolContext.Courses where c.Department.DepartmentID == departmentID select new { CourseID = c.CourseID, CourseTitle = c.Title, CourseCredits = c.Credits };// Bind the GridView control to the courseInfo collection.courseGridView.DataSource = courseInfo;courseGridView.DataBind();
<body> <form id="form1" runat="server"> <asp:DropDownList ID="departmentList" runat="server" AutoPostBack="True" DataSourceID="departmentDS" DataTextField="Name" DataValueField="DepartmentID" Height="19px" Width="161px"> </asp:DropDownList> <asp:EntityDataSource ID="departmentDS" runat="server" ConnectionString="name=SchoolEntities" DefaultContainerName="SchoolEntities" EnableFlattening="False" EntitySetName="Departments" Select="it.[DepartmentID], it.[Name]"> </asp:EntityDataSource> <asp:GridView ID="courseGridView" runat="server"> </asp:GridView> </form></body>
using System;using System.Collections.Generic;using System.Linq;using System.Web;using System.Web.UI;using System.Web.UI.WebControls;using System.Data.Objects;namespace CourseManagerWeb{ public partial class _Default : System.Web.UI.Page { // Create an ObjectContext based on SchoolEntity. private SchoolEntities schoolContext; protected void Page_PreRenderComplete(object sender, EventArgs e) { // Force initial GridView update. departmentList_SelectedIndexChanged(this.Page, new EventArgs()); } protected void Page_Load(object sender, EventArgs e) { // Initialize the data context. schoolContext = new SchoolEntities(); } protected void departmentList_SelectedIndexChanged(object sender, EventArgs e) { // Get the department ID. Int32 departmentID = Convert.ToInt32(departmentList.SelectedValue); // Select course information based on department ID. var courseInfo = from c in schoolContext.Courses where c.Department.DepartmentID == departmentID select new { CourseID = c.CourseID, CourseTitle = c.Title, CourseCredits = c.Credits }; // Bind the GridView control to the courseInfo collection. courseGridView.DataSource = courseInfo; courseGridView.DataBind(); } }}
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