asp.net/ajax

asp.net/ajax 1.
http://www.asp.net/AJAX/Documentation/Live/tutorials/UsingUpdatePanelControls.aspx

管理掌握触发器/以编程方式刷新一个UpdatePanel

触发一个UpdatePanel控件使UpdatePanel控件开始刷新的控件,要通过ScriptManager在Page页上"注册".这,通常会自动发生,当子控件在UpdatePanel控件的ContentTemplate内的时候。你也可以明确地指定触发器---通过使用UpdatePanel控件的Triggers集合UpdatePanel1.Triggers是UpdatePanel1不是UpdatePanel!另外,你也可以在你的页面的服务器端代码(cs代码内)编程(动词)指定触发器以引起UpdatePanel控件的刷新动作.万一触发器控件在"设计时"不可用,你也可以注册(动词)控件成为(动词)一个触发器---通过使用ScriptManager控件的RegisterAsyncPostBackControl(Control)方法,当然使用时是ScriptManager1而不是ScriptManager!
被以编程方式指定为触发器的控件必须被注册----在任何一次当PostBack发生的时候。我们要求你把调用UpdatePanel控件的RegisterAsyncPostBackControl(Control)方法的代码放在你的页面的Page_Load事件里，象下面这样：

protected void Page_Load()

{

ScriptManager1.RegisterAsyncPostBackControl(SurveyDataList);

}

要以编程方式"刷新"UpdatePanel控件,你可以主动调用UpdatePanel控件的Update()方法.这是很有用的,尤其是在必须在服务器端执行一些处理-----在刷新UpdatePanel控件之前.代码:

protected void ChoicesRadioButtonList_SelectedIndexChanged(object sender, EventArgs e)

{

SortedList answers = this.AnsweredQuestions;

RadioButtonList r = (RadioButtonList)sender;

answers[r.ToolTip] = r.SelectedValue;

this.AnsweredQuestions = answers;

ResultsList.DataSource = this.AnsweredQuestions;

ResultsList.DataBind();

if (this.AnsweredQuestions.Count == SurveyDataList.Items.Count)

SubmitButton.Visible = true;

UpdatePanel1.Update();

}

下面的例子展示了一个页面,该页面注册了一个控件作为触发器----通过使用RegisterAsyncPostBackControl(Control)方法，并且以编程方式刷新一个UpdatePanel控件-----通过使用Update()方法。

<%@ Page Language="C#" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"

"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

protected SortedList AnsweredQuestions

{

get { return (SortedList)(ViewState["AnsweredQuestions"] ?? new SortedList()); }

set { ViewState["AnsweredQuestions"] = value; }

}

protected void Page_Load()

{

ScriptManager1.RegisterAsyncPostBackControl(SurveyDataList);

}

protected void ChoicesRadioButtonList_SelectedIndexChanged(object sender, EventArgs e)

{

SortedList answers = this.AnsweredQuestions;

RadioButtonList r = (RadioButtonList)sender;

answers[r.ToolTip] = r.SelectedValue;

this.AnsweredQuestions = answers;

ResultsList.DataSource = this.AnsweredQuestions;

ResultsList.DataBind();

if (this.AnsweredQuestions.Count == SurveyDataList.Items.Count)

SubmitButton.Visible = true;

UpdatePanel1.Update();

}

protected void SubmitButton_Click(object sender, EventArgs e)

{

// Submit responses.

}

</script>

<title>Registering Controls as Async Postback Controls</title>

.AnswerFloatPanelStyle {

background-color: bisque;

position: absolute;

right: 10px;

height: 130px;

width: 150px;

border-right: silver thin solid; border-top: silver thin solid;

border-left: silver thin solid; border-bottom: silver thin solid;

}

</style>

</head>

<body>

<div>

<asp:ScriptManager ID="ScriptManager1" runat="server" />

<asp:UpdatePanel ID="UpdatePanel1" UpdateMode="Conditional" runat="server">

Completed Questions:

<asp:DataList ID="ResultsList" runat="server">

<asp:Label ID="ResultQuestion" runat="server" Text='<%# Eval("Key") %>' />

<asp:Label ID="ResultAnswer" runat="server" Text='<%# Eval("Value") %>' />

</ItemTemplate>

</asp:DataList>

<asp:Button ID="SubmitButton" Text="Submit" runat="server" Visible="false"

OnClick="SubmitButton_Click" />

</p>

<asp:Label ID="Message" runat="Server" />

</ContentTemplate>

</asp:UpdatePanel>

</div>

<asp:XmlDataSource ID="SurveyDataSource"

runat="server"

XPath="/Questions/Question"

DataFile="~/App_Data/SurveyQuestions.xml"/>

<asp:DataList

ID="SurveyDataList"

DataSourceID="SurveyDataSource"

runat="server">

<tr>

<asp:Label id="QuestionLabel" Text='<%# XPath("@Title")%>' runat="server" />

</td>

</tr>

<asp:RadioButtonList ID="ChoicesRadioButtonList" runat="server"

DataSource='<%#XPathSelect("Choices/Choice") %>'

DataTextField="InnerText" DataValueField="InnerText"

AutoPostBack="True"

ToolTip='<%# "Question" + XPath("@ID") %>'

OnSelectedIndexChanged="ChoicesRadioButtonList_SelectedIndexChanged"/>

</td></tr>

</table>

<hr />

</ItemTemplate>

</asp:DataList>

</div>

</form>

</body>

</html>

2007年9月13日