Building a Web Application->Working with Server Controls
ASP.NET server controls //服务器端控件are identified //识别within a page using declarative tags//声明的标签 that contain a runat="server" attribute. The following example declares//声明,陈述,展示 three <asp:label runat="server"> server controls //服务器端控件and customizes //用户化the text and style properties //样式属性of each one individually. //个别地
The following sample demonstrates how to use the Response.Redirect method //方法to pass parameters //传递参数to another target page//目标页面. It also demonstrates how to easily get access to //获得,可以使用these parameters//参数 from the target page.
C# Controls1.aspx
<%@ Page Language="C#" %>
<html>
<body>
<h3><font face="Verdana">Declaring Server Controls</font></h3>
This sample demonstrates how to declare the <asp:label> server control and
manipulate its properties within a page.
<p>
<hr>
<asp:label id="Message1" font-size="16" font-bold="true" forecolor="red" runat=server>This is Message One</asp:label>
<br>
<asp:label id="Message2" font-size="20" font-italic="true" forecolor="blue" runat=server>This is Message Two</asp:label>
<br>
<asp:label id="Message3" font-size="24" font-underline="true" forecolor="green" runat=server>This is Message Three</asp:label>
</body>
</html>
<%@ Page Language="C#" %><html> <body> <h3><font face="Verdana">Declaring Server Controls</font></h3> This sample demonstrates how to declare the <asp:label> server control and manipulate its properties within a page. <p> <hr> <asp:label id="Message1" font-size="16" font-bold="true" forecolor="red" runat=server>This is Message One</asp:label> <br> <asp:label id="Message2" font-size="20" font-italic="true" forecolor="blue" runat=server>This is Message Two</asp:label> <br> <asp:label id="Message3" font-size="24" font-underline="true" forecolor="green" runat=server>This is Message Three</asp:label> </body></html>Manipulating //处理Server Controls//服务器端控件
You can programmatically //计划性地identify //识别an individual ASP.NET server control //服务器端控件within a page by providing it with an id attribute. You can use this id reference //id参数 to programmatically //计划性地 manipulate the server control's object model //对象模型at run time//运行时. For example, the following sample demonstrates //举例说明how a page developer could programmatically//计划性地 set an <asp:label runat="server"> control's Text property within the Page_Load event//页面载入事件.C# Controls2.aspx
<html>
<script language="C#" runat="server">
void Page_Load(Object Src, EventArgs E) {
Message.Text = "You last accessed this page at: " + DateTime.Now;
}
</script>
<body>
<h3><font face="Verdana">Manipulating Server Controls</font></h3>
This sample demonstrates how to manipulate the <asp:label> server control within
the Page_Load event to output the current time.
<p>
<hr>
<asp:label id="Message" font-size="24" font-bold="true" runat=server/>
</body>
</html>
<html> <script language="C#" runat="server"> void Page_Load(Object Src, EventArgs E) {
Message.Text = "You last accessed this page at: " + DateTime.Now; } </script> <body> <h3><font face="Verdana">Manipulating Server Controls</font></h3> This sample demonstrates how to manipulate the <asp:label> server control within the Page_Load event to output the current time. <p> <hr> <asp:label id="Message" font-size="24" font-bold="true" runat=server/> </body></html>Handling Control Events//处理控件事件
ASP.NET server controls //服务器端控件can optionally//可选择地 expose //揭露,展示,阐述and raise//上升,增高,升起,饲养 server events//服务器事件, which can be handled by page developers. A page developer may accomplish//完成,实现 this by declaratively //宣言地 wiring an event to a control (where the attribute name //属性名称of an event wireup //indicates the event name and the attribute value//属性值 indicates the name of a method//方法名 to call//调用). For example, the following code example demonstrates//举例说明 how to wire an OnClick event //单击事件to a button control.C# Controls3.aspx
<html>
<script language="C#" runat="server">
void EnterBtn_Click(Object Src, EventArgs E) {
Message.Text = "Hi " + Name.Text + ", welcome to ASP.NET!";
}
</script>
<body>
<h3><font face="Verdana">Handling Control Action Events</font></h3>
<p>
This sample demonstrates how to access a <asp:textbox> server control within the "Click"
event of a <asp:button>, and use its content to modify the text of a <asp:label>.
<p>
<hr>
<form action="controls3.aspx" runat=server>
<font face="Verdana">
Please enter your name: <asp:textbox id="Name" runat=server/>
<asp:button text="Enter" Onclick="EnterBtn_Click" runat=server/>
<p>
<asp:label id="Message" runat=server/>
</font>
</form>
</body>
</html>
<html> <script language="C#" runat="server"> void EnterBtn_Click(Object Src, EventArgs E) { Message.Text = "Hi " + Name.Text + ", welcome to ASP.NET!"; } </script> <body> <h3><font face="Verdana">Handling Control Action Events</font></h3> <p> This sample demonstrates how to access a <asp:textbox> server control within the "Click" event of a <asp:button>, and use its content to modify the text of a <asp:label>. <p> <hr> <form action="controls3.aspx" runat=server> <font face="Verdana"> Please enter your name: <asp:textbox id="Name" runat=server/> <asp:button text="Enter" Onclick="EnterBtn_Click" runat=server/> <p> <asp:label id="Message" runat=server/> </font> </form> </body></html>Handling Multiple Control Events//处理多个控件事件
Event handlers//事件处理器 provide a clean way for page developers to structure logic//结构逻辑 within an ASP.NET page. For example, the following sample demonstrates how to wire //电报,接收and handle//处理 four button events on a single page//单独的页面中.C# Controls4.aspx
<html>
<script language="C#" runat="server">
void AddBtn_Click(Object Src, EventArgs E) {
if (AvailableFonts.SelectedIndex != -1) {
InstalledFonts.Items.Add(new ListItem(AvailableFonts.SelectedItem.Value));
AvailableFonts.Items.Remove(AvailableFonts.SelectedItem.Value);
}
}
void AddAllBtn_Click(Object Src, EventArgs E) {
while (AvailableFonts.Items.Count != 0) {
InstalledFonts.Items.Add(new ListItem(AvailableFonts.Items[0].Value));
AvailableFonts.Items.Remove(AvailableFonts.Items[0].Value);
}
}
void RemoveBtn_Click(Object Src, EventArgs E) {
if (InstalledFonts.SelectedIndex != -1) {
AvailableFonts.Items.Add(new ListItem(InstalledFonts.SelectedItem.Value));
InstalledFonts.Items.Remove(InstalledFonts.SelectedItem.Value);
}
}
void RemoveAllBtn_Click(Object Src, EventArgs E) {
while (InstalledFonts.Items.Count != 0) {
AvailableFonts.Items.Add(new ListItem(InstalledFonts.Items[0].Value));
InstalledFonts.Items.Remove(InstalledFonts.Items[0].Value);
}
}
</script>
<body>
<h3><font face="Verdana">Handling Multiple Control Action Events</font></h3>
<p>
This sample demonstrates how to handle multiple control action events raised from
different <asp:button> controls.
<p>
<hr>
<form action="controls4.aspx" runat=server>
<table>
<tr>
<td>
Available Fonts
</td>
<td>
<!-- Filler -->
</td>
<td>
Installed Fonts
</td>
</tr>
<tr>
<td>
<asp:listbox id="AvailableFonts" width="100px" runat=server>
<asp:listitem>Roman</asp:listitem>
<asp:listitem>Arial Black</asp:listitem>
<asp:listitem>Garamond</asp:listitem>
<asp:listitem>Somona</asp:listitem>
<asp:listitem>Symbol</asp:listitem>
</asp:listbox>
</td>
<td>
<!-- Filler -->
</td>
<td>
<asp:listbox id="InstalledFonts" width="100px" runat=server>
<asp:listitem>Times</asp:listitem>
<asp:listitem>Helvetica</asp:listitem>
<asp:listitem>Arial</asp:listitem>
</asp:listbox>
</td>
</tr>
<tr>
<td>
<!-- Filler -->
</td>
<td>
<asp:button text="<<" OnClick="RemoveAllBtn_Click" runat=server/>
<asp:button text="<" OnClick="RemoveBtn_Click" runat=server/>
<asp:button text=">" OnClick="AddBtn_Click" runat=server/>
<asp:button text=">>" OnClick="AddAllBtn_Click" runat=server/>
</td>
<td>
<!-- Filler -->
</td>
</tr>
</table>
</form>
</body>
</html>
<html> <script language="C#" runat="server"> void AddBtn_Click(Object Src, EventArgs E) { if (AvailableFonts.SelectedIndex != -1) {
InstalledFonts.Items.Add(new ListItem(AvailableFonts.SelectedItem.Value)); AvailableFonts.Items.Remove(AvailableFonts.SelectedItem.Value); } } void AddAllBtn_Click(Object Src, EventArgs E) { while (AvailableFonts.Items.Count != 0) { InstalledFonts.Items.Add(new ListItem(AvailableFonts.Items[0].Value)); AvailableFonts.Items.Remove(AvailableFonts.Items[0].Value); } } void RemoveBtn_Click(Object Src, EventArgs E) { if (InstalledFonts.SelectedIndex != -1) { AvailableFonts.Items.Add(new ListItem(InstalledFonts.SelectedItem.Value)); InstalledFonts.Items.Remove(InstalledFonts.SelectedItem.Value); } } void RemoveAllBtn_Click(Object Src, EventArgs E) { while (InstalledFonts.Items.Count != 0) { AvailableFonts.Items.Add(new ListItem(InstalledFonts.Items[0].Value)); InstalledFonts.Items.Remove(InstalledFonts.Items[0].Value); } } </script> <body> <h3><font face="Verdana">Handling Multiple Control Action Events</font></h3> <p> This sample demonstrates how to handle multiple control action events raised from different <asp:button> controls. <p> <hr> <form action="controls4.aspx" runat=server> <table> <tr> <td> Available Fonts </td> <td> <!-- Filler --> </td> <td> Installed Fonts </td> </tr> <tr> <td> <asp:listbox id="AvailableFonts" width="100px" runat=server> <asp:listitem>Roman</asp:listitem> <asp:listitem>Arial Black</asp:listitem> <asp:listitem>Garamond</asp:listitem> <asp:listitem>Somona</asp:listitem> <asp:listitem>Symbol</asp:listitem> </asp:listbox> </td> <td> <!-- Filler --> </td> <td> <asp:listbox id="InstalledFonts" width="100px" runat=server> <asp:listitem>Times</asp:listitem> <asp:listitem>Helvetica</asp:listitem> <asp:listitem>Arial</asp:listitem> </asp:listbox> </td> </tr> <tr> <td> <!-- Filler --> </td> <td> <asp:button text="<<" OnClick="RemoveAllBtn_Click" runat=server/> <asp:button text="<" OnClick="RemoveBtn_Click" runat=server/> <asp:button text=">" OnClick="AddBtn_Click" runat=server/> <asp:button text=">>" OnClick="AddAllBtn_Click" runat=server/> </td> <td> <!-- Filler --> </td> </tr> </table> </form> </body></html>Performing Page Navigation//实现页面导航 (Scenario//情节,剧情 1)
Page navigation among multiple pages is a common scenario in virtually//几乎,差不多 all Web applications. The following sample demonstrates how to use the <asp:hyperlink runat=server> control to navigate to//导航到 another page (passing custom query string parameters //查询字符串参数along //向着,沿the way). The sample then demonstrates how to easily get access to //获得these query string parameters //查询字符串参数from the target page//目标页面.C# Controls5.aspx
<html>
<script language="C#" runat="server">
void Page_Load(Object Src, EventArgs E) {
Random randomGenerator = new Random(DateTime.Now.Millisecond);
int randomNum = randomGenerator.Next(0, 3);
switch(randomNum) {
case 0:
Name.Text = "Scott";
break;
case 1:
Name.Text = "Fred";
break;
case 2:
Name.Text = "Adam";
break;
}
AnchorLink.NavigateUrl = "controls_navigationtarget_cs.aspx?name=" + System.Web.HttpUtility.UrlEncode(Name.Text);
}
</script>
<body>
<h3><font face="Verdana">Performing Page Navigation (Scenario 1)</font></h3>
<p>
This sample demonstrates how to generate a HTML Anchor tag that will cause the client to
navigate to a new page when he/she clicks it within the browser.
<p>
<hr>
<p>
<asp:hyperlink id="AnchorLink" font-size=24 runat=server>
Hi <asp:label id="Name" runat=server/> please click this link!
</asp:hyperlink>
</body>
</html>
<html> <script language="C#" runat="server"> void Page_Load(Object Src, EventArgs E) { Random randomGenerator = new Random(DateTime.Now.Millisecond); int randomNum = randomGenerator.Next(0, 3); switch(randomNum) { case 0: Name.Text = "Scott"; break; case 1: Name.Text = "Fred"; break; case 2: Name.Text = "Adam"; break; } AnchorLink.NavigateUrl = "controls_navigationtarget_cs.aspx?name=" + System.Web.HttpUtility.UrlEncode(Name.Text); } </script> <body> <h3><font face="Verdana">Performing Page Navigation (Scenario 1)</font></h3> <p> This sample demonstrates how to generate a HTML Anchor tag that will cause the client to navigate to a new page when he/she clicks it within the browser. <p> <hr> <p> <asp:hyperlink id="AnchorLink" font-size=24 runat=server> Hi <asp:label id="Name" runat=server/> please click this link! </asp:hyperlink> </body></html>Performing Page Navigation //实现页面导航(Scenario //情景,剧情2)
Not all page navigation scenarios are initiated //初始化,开始through hyperlinks on the client//客户端. Client-side page//客户端页面 redirects or navigations can also be initiated //初始化,开始from the server//服务器端 by an ASP.NET page developer by calling the Response.Redirect(url) method. This is typically //典型地done when server-side//服务器端 validation //确认is required on some client input//客户端输入 before the navigation actually //实际上takes place//发生.The following sample demonstrates how to use the Response.Redirect method //方法to pass parameters //传递参数to another target page//目标页面. It also demonstrates how to easily get access to //获得,可以使用these parameters//参数 from the target page.
C# Controls6.aspx
<html>
<script language="C#" runat="server">
void EnterBtn_Click(Object Src, EventArgs E) {
// Navigate to a new page (passing name as a querystring argument) if
// user has entered a valid name value in the <asp:textbox>
if (Name.Text != "") {
Response.Redirect("Controls_NavigationTarget_cs.aspx?name=" + System.Web.HttpUtility.UrlEncode(Name.Text));
}
else {
Message.Text = "Hey! Please enter your name in the textbox!";
}
}
</script>
<body>
<h3><font face="Verdana">Performing Page Navigation (Scenario 2)</font></h3>
<p>
This sample demonstrates how to navigate to a new page from within a <asp:button> click event,
passing a <asp:textbox> value as a querystring argument (validating first that the a legal
textbox value has been specified).
<p>
<hr>
<form action="controls6.aspx" runat=server>
<font face="Verdana">
Please enter your name: <asp:textbox id="Name" runat=server/>
<asp:button text="Enter" Onclick="EnterBtn_Click" runat=server/>
<p>
<asp:label id="Message" forecolor="red" font-bold="true" runat=server/>
</font>
</form>
</body>
</html>
<html> <script language="C#" runat="server"> void EnterBtn_Click(Object Src, EventArgs E) { // Navigate to a new page (passing name as a querystring argument) if // user has entered a valid name value in the <asp:textbox> if (Name.Text != "") { Response.Redirect("Controls_NavigationTarget_cs.aspx?name=" + System.Web.HttpUtility.UrlEncode(Name.Text)); } else { Message.Text = "Hey! Please enter your name in the textbox!"; } } </script> <body> <h3><font face="Verdana">Performing Page Navigation (Scenario 2)</font></h3> <p> This sample demonstrates how to navigate to a new page from within a <asp:button> click event, passing a <asp:textbox> value as a querystring argument (validating first that the a legal textbox value has been specified). <p> <hr> <form action="controls6.aspx" runat=server> <font face="Verdana"> Please enter your name: <asp:textbox id="Name" runat=server/> <asp:button text="Enter" Onclick="EnterBtn_Click" runat=server/> <p> <asp:label id="Message" forecolor="red" font-bold="true" runat=server/> </font> </form> </body></html>
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