hig*_*gsy 9 c# asp.net repeater session-state
我的页面上有两个中继器.第一个转发器中有一个LinkButton,带有命令名和命令规范.单击linkbutton时,commandarguement的值应该存储在包含List的Session中.然后我使用Session List的值绑定第二个转发器.
我有两个问题:
1)我在OnInit事件中绑定了第二个转发器.在init事件之后执行第一个转发器中的LinkButton时执行的事件处理程序 - 因此,当数据绑定发生时,新值尚未添加到会话中.我不能在init事件之后绑定数据,因为第二个转发器中的控件需要使用viewstate(或其他)来维护.
2)在第二个中继器中有两个下拉列表.两者都是在转发器itemdatabound事件中的数据绑定.当第一个DDL更改时,我需要过滤第二个DDL中的值.但这并没有发生.
为了更清楚的例子,我已经从我的应用程序中删除了代码并创建了一个非常简单的aspx页面 - 所有代码都在下面.感谢已经帮助过这个的Bobby.
真的希望有人可以帮忙,因为我难倒!
标记:
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Repeater-Viewstate.aspx.cs" Inherits="test_Repeater_Viewstate" ViewStateMode="Enabled" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title></title>
</head>
<body>
<form id="form1" runat="server">
<div>
<h1>Repeater Test</h1>
<h2>Repeater 1</h2>
<asp:Repeater runat="server" Visible="true" ID="rptListItems">
<ItemTemplate>
Image ID: <asp:Literal ID="ImageID" runat="server" />
<asp:LinkButton runat="server" CommandName="SelectImage" Text="Add to list" ID="AddToListCommand" />
<hr />
</ItemTemplate>
</asp:Repeater>
<h2>Repeater 2</h2>
<asp:Repeater runat="server" Visible="true" ID="rptSelectedItems" ViewStateMode="Enabled">
<ItemTemplate>
The value of the item you selected is: <asp:TextBox runat="server" ID="ImageIDInput"/>
<asp:DropDownList runat="server" ID="OptionsInput" AppendDataBoundItems="true" AutoPostBack="true" >
<asp:ListItem Text="Please choose..." Value="0" />
</asp:DropDownList>
<asp:DropDownList runat="server" ID="AttributesInput" runat="server" AppendDataBoundItems="true">
<asp:ListItem Text="Please choose..." Value="0" />
</asp:DropDownList>
<hr style="clear: both;" />
</ItemTemplate>
</asp:Repeater>
<asp:Button runat="server" Text="Postback" />
</div>
</form>
</body>
</html>
代码背后:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
public partial class test_Repeater_Viewstate : System.Web.UI.Page
{
//DUMMY Data for 1st Repeater
public class MyRepeaterDataSource {
public int ID { get; set; }
public string Title { get; set; }
}
private List<MyRepeaterDataSource> _items;
public List<MyRepeaterDataSource> Items {
get {
if (_items == null)
_items = new List<MyRepeaterDataSource>();
return _items;
}
set {
_items = value;
}
}
//END dummy data
//DUMMY data for 1st dropdownlist in second repeater
public class FirstDDLClass {
public int ID { get; set; }
public string Title { get; set; }
}
private List<FirstDDLClass> _firstDDLItems;
public List<FirstDDLClass> FirstDDLItems {
get {
if (_firstDDLItems == null)
_firstDDLItems = new List<FirstDDLClass>();
return _firstDDLItems;
}
set {
_firstDDLItems = value;
}
}
//DUMMY data for 2nd dropdownlist in second repeater
public class SecondDDLClass {
public int ID { get; set; }
public int ForeignKey { get; set; }
public string Title { get; set; }
}
private List<SecondDDLClass> _secondDDLItems;
public List<SecondDDLClass> SecondDDLItems {
get {
if (_secondDDLItems == null)
_secondDDLItems = new List<SecondDDLClass>();
return _secondDDLItems;
}
set {
_secondDDLItems = value;
}
}
public List<string> SelectedItems {
get {
if (Session["SelectedItems"] == null)
Session["SelectedItems"] = new List<string>();
return (List<string>)(Session["SelectedItems"]);
}
set {
Session["SelectedItems"] = value;
}
}
protected override void OnInit(EventArgs e) {
//register events
this.rptListItems.ItemDataBound += new RepeaterItemEventHandler(rptListItems_ItemDataBound);
this.rptListItems.ItemCommand += new RepeaterCommandEventHandler(rptListItems_ItemCommand);
this.rptSelectedItems.ItemDataBound += new RepeaterItemEventHandler(rptSelectedItems_ItemDataBound);
//create a dummy list to populate first repeater
MyRepeaterDataSource dataSource1 = new MyRepeaterDataSource();
dataSource1.ID = 1;
dataSource1.Title = "Item 1";
Items.Add(dataSource1);
MyRepeaterDataSource dataSource2 = new MyRepeaterDataSource();
dataSource2.ID = 2;
dataSource2.Title = "Item 2";
Items.Add(dataSource2);
MyRepeaterDataSource dataSource3 = new MyRepeaterDataSource();
dataSource3.ID = 3;
dataSource3.Title = "Item 3";
Items.Add(dataSource3);
MyRepeaterDataSource dataSource4 = new MyRepeaterDataSource();
dataSource4.ID = 4;
dataSource4.Title = "Item 4";
Items.Add(dataSource4);
//create a dummy list to populate the first dropdownlist in the second repeater
FirstDDLClass class1 = new FirstDDLClass();
class1.ID = 1;
class1.Title = "Option 1";
FirstDDLItems.Add(class1);
FirstDDLClass class2 = new FirstDDLClass();
class2.ID = 2;
class2.Title = "Option 2";
FirstDDLItems.Add(class2);
//create a dummy list to populate the second dropdownlist in the second repeater
SecondDDLClass class3 = new SecondDDLClass();
class3.ID = 1;
class3.ForeignKey = 1;
class3.Title = "Attribute 1";
SecondDDLItems.Add(class3);
SecondDDLClass class4 = new SecondDDLClass();
class4.ID = 1;
class4.ForeignKey = 1;
class4.Title = "Attribute 2";
SecondDDLItems.Add(class4);
SecondDDLClass class5 = new SecondDDLClass();
class5.ID = 1;
class5.ForeignKey = 2;
class5.Title = "Attribute 3";
SecondDDLItems.Add(class5);
if (!this.Page.IsPostBack) {
//bind 1st repeater
this.rptListItems.DataSource = Items;
this.rptListItems.DataBind();
}
//bind second repeater
this.rptSelectedItems.DataSource = SelectedItems;
this.rptSelectedItems.DataBind();
base.OnInit(e);
}
protected void Page_Load(object sender, EventArgs e)
{
}
void rptListItems_ItemDataBound(object sender, RepeaterItemEventArgs e) {
Literal imageIDLiteral = e.Item.FindControl("ImageID") as Literal;
if (imageIDLiteral is Literal) {
imageIDLiteral.Text = DataBinder.Eval(e.Item.DataItem, "ID").ToString();
}
LinkButton linkButton = e.Item.FindControl("AddToListCommand") as LinkButton;
if (linkButton is LinkButton) {
linkButton.CommandArgument = DataBinder.Eval(e.Item.DataItem, "ID").ToString();
}
}
void rptListItems_ItemCommand(object source, RepeaterCommandEventArgs e) {
switch (e.CommandName) {
case "SelectImage":
this.SelectedItems.Add(e.CommandArgument.ToString());
break;
}
}
void rptSelectedItems_ItemDataBound(object sender, RepeaterItemEventArgs e) {
switch (e.Item.ItemType) {
case ListItemType.AlternatingItem:
case ListItemType.Item:
TextBox textBox = e.Item.FindControl("ImageIDInput") as TextBox;
if (textBox is TextBox) {
textBox.Text = e.Item.DataItem.ToString();
}
DropDownList ddl1 = e.Item.FindControl("OptionsInput") as DropDownList;
if (ddl1 is DropDownList) {
ddl1.DataValueField = "ID";
ddl1.DataTextField = "Title";
ddl1.DataSource = this.FirstDDLItems;
ddl1.DataBind();
}
DropDownList ddl2 = e.Item.FindControl("AttributesInput") as DropDownList;
if (ddl2 is DropDownList) {
ddl2.DataValueField = "ID";
ddl2.DataTextField = "Title";
if (ddl1.SelectedIndex != 0) {
ddl2.DataSource = this.SecondDDLItems.Where(f => f.ForeignKey == Convert.ToInt32(ddl1.SelectedValue));
ddl2.DataBind();
}
}
break;
}
}
}
先谢谢你们
人
如果添加以下代码：
protected void OptionsInput_SelectedIndexChanged(object sender, EventArgs e)
{
DropDownList optionsInput = sender as DropDownList;
DropDownList ddl2 = optionsInput.Parent.FindControl("AttributesInput") as DropDownList;
if (ddl2 is DropDownList)
{
ddl2.DataValueField = "ID";
ddl2.DataTextField = "Title";
if (optionsInput.SelectedIndex != 0)
{
ddl2.DataSource = this.SecondDDLItems.Where(f => f.ForeignKey == Convert.ToInt32(optionsInput.SelectedValue));
ddl2.DataBind();
}
}
}
以及以下标记：
<asp:DropDownList runat="server" ID="OptionsInput" AppendDataBoundItems="true" AutoPostBack="true" OnSelectedIndexChanged="OptionsInput_SelectedIndexChanged" >
（具体来说，添加 OnSelectedIndexChanged="OptionsInput_SelectedIndexChanged"）
这对我有用。
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