HtmlSelectBuilder 类
定义
重要
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与分析器进行交互以生成 HtmlSelect 控件。
public ref class HtmlSelectBuilder : System::Web::UI::ControlBuilderpublic class HtmlSelectBuilder : System.Web.UI.ControlBuildertype HtmlSelectBuilder = class
inherit ControlBuilderPublic Class HtmlSelectBuilder
Inherits ControlBuilder- 继承
示例
下面的代码示例演示如何创建自定义控件，该控件定义自定义HtmlSelectBuilderHtmlSelect控件的<option>两种类型的子元素，然后以不同的方式处理每种类型。
<%@ Page Language="C#"%>
<%@ Register TagPrefix="aspSample" Namespace="Samples.AspNet.CS.Controls" Assembly="Samples.AspNet.CS" %>
<!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>HtmlSelectBuilder Example</title>
</head>
<body>
<form id="Form1" runat="server">
<h3>HtmlSelectBuilder Example</h3>
<aspSample:CustomHtmlSelect
id="customhtmlselect1"
runat="server">
<aspSample:MyOption1 optionid="option1" value="1" text="item 1"/>
<aspSample:MyOption1 optionid="option2" value="2" text="item 2"/>
<aspSample:MyOption2 optionid="option3" value="3" text="item 3"/>
<aspSample:MyOption2 optionid="option4" value="4" text="item 4"/>
</aspSample:CustomHtmlSelect>
</form>
</body>
</html>
<%@ Page Language="VB"%>
<%@ Register TagPrefix="aspSample" Namespace="Samples.AspNet.VB.Controls" Assembly="Samples.AspNet.VB" %>
<!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>HtmlSelectBuilder Example</title>
</head>
<body>
<form id="Form1" runat="server">
<h3>HtmlSelectBuilder Example</h3>
<aspSample:CustomHtmlSelect
id="customhtmlselect1"
runat="server">
<aspSample:MyOption1 optionid="option1" value="1" text="item 1"/>
<aspSample:MyOption1 optionid="option2" value="2" text="item 2"/>
<aspSample:MyOption2 optionid="option3" value="3" text="item 3"/>
<aspSample:MyOption2 optionid="option4" value="4" text="item 4"/>
</aspSample:CustomHtmlSelect>
</form>
</body>
</html>
using System;
using System.Security.Permissions;
using System.Collections;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.HtmlControls;
namespace Samples.AspNet.CS.Controls
{
// Define a type of child control for the custom HtmlSelect control.
public class MyOption1
{
string _id;
string _value;
string _text;
public string optionid
{
get
{ return _id; }
set
{ _id = value; }
}
public string value
{
get
{ return _value; }
set
{ _value = value; }
}
public string text
{
get
{ return _text; }
set
{ _text = value; }
}
}
// Define a type of child control for the custom HtmlSelect control.
public class MyOption2
{
string _id;
string _value;
string _text;
public string optionid
{
get
{ return _id; }
set
{ _id = value; }
}
public string value
{
get
{ return _value; }
set
{ _value = value; }
}
public string text
{
get
{ return _text; }
set
{ _text = value; }
}
}
// Define a custom HtmlSelectBuilder control.
public class MyHtmlSelectBuilder : HtmlSelectBuilder
{
[AspNetHostingPermission(SecurityAction.Demand, Level = AspNetHostingPermissionLevel.Minimal)]
public override Type GetChildControlType(string tagName, IDictionary attribs)
{
// Distinguish between two possible types of child controls.
if (tagName.ToLower().EndsWith("myoption1"))
{
return typeof(MyOption1);
}
else if (tagName.ToLower().EndsWith("myoption2"))
{
return typeof(MyOption2);
}
return null;
}
}
[ControlBuilderAttribute(typeof(MyHtmlSelectBuilder))]
public class CustomHtmlSelect : HtmlSelect
{
// Override AddParsedSubObject to treat the two types
// of child controls differently.
protected override void AddParsedSubObject(object obj)
{
string _outputtext;
if (obj is MyOption1)
{
_outputtext = "option group 1: " + ((MyOption1)obj).text;
ListItem li = new ListItem(_outputtext, ((MyOption1)obj).value);
base.Items.Add(li);
}
if (obj is MyOption2)
{
_outputtext = "option group 2: " + ((MyOption2)obj).text;
ListItem li = new ListItem(_outputtext, ((MyOption2)obj).value);
base.Items.Add(li);
}
}
}
}
Imports System.Security.Permissions
Imports System.Collections
Imports System.Web
Imports System.Web.UI
Imports System.Web.UI.WebControls
Imports System.Web.UI.HtmlControls
Namespace Samples.AspNet.VB.Controls
' Define a type of child control for the custom HtmlSelect control.
Public Class MyOption1
Private _id As String
Private _value As String
Private _text As String
Public Property optionid() As String
Get
Return _id
End Get
Set(ByVal value As String)
_id = value
End Set
End Property
Public Property value() As String
Get
Return _value
End Get
Set(ByVal value As String)
_value = value
End Set
End Property
Public Property [text]() As String
Get
Return _text
End Get
Set(ByVal value As String)
_text = value
End Set
End Property
End Class
' Define a type of child control for the custom HtmlSelect control.
Public Class MyOption2
Private _id As String
Private _value As String
Private _text As String
Public Property optionid() As String
Get
Return _id
End Get
Set(ByVal value As String)
_id = value
End Set
End Property
Public Property value() As String
Get
Return _value
End Get
Set(ByVal value As String)
_value = value
End Set
End Property
Public Property [text]() As String
Get
Return _text
End Get
Set(ByVal value As String)
_text = value
End Set
End Property
End Class
' Define a custom HtmlSelectBuilder control.
Public Class MyHtmlSelectBuilder
Inherits HtmlSelectBuilder
<AspNetHostingPermission(SecurityAction.Demand, Level:=AspNetHostingPermissionLevel.Minimal)> _
Public Overrides Function GetChildControlType(ByVal tagName As String, ByVal attribs As IDictionary) As Type
' Distinguish between two possible types of child controls.
If tagName.ToLower().EndsWith("myoption1") Then
Return GetType(MyOption1)
ElseIf tagName.ToLower().EndsWith("myoption2") Then
Return GetType(MyOption2)
End If
Return Nothing
End Function
End Class
<ControlBuilderAttribute(GetType(MyHtmlSelectBuilder))> _
Public Class CustomHtmlSelect
Inherits HtmlSelect
' Override AddParsedSubObject to treat the two types
' of child controls differently.
Protected Overrides Sub AddParsedSubObject(ByVal obj As Object)
Dim _outputtext As String
If TypeOf obj Is MyOption1 Then
_outputtext = "option group 1: " + CType(obj, MyOption1).text
Dim li As New ListItem(_outputtext, CType(obj, MyOption1).value)
MyBase.Items.Add(li)
End If
If TypeOf obj Is MyOption2 Then
_outputtext = "option group 2: " + CType(obj, MyOption2).text
Dim li As New ListItem(_outputtext, CType(obj, MyOption2).value)
MyBase.Items.Add(li)
End If
End Sub
End Class
End Namespace
注解
该 HtmlSelectBuilder 控件与页面分析程序交互以生成控件 HtmlSelect 。 使用 HtmlSelectBuilder 控件自定义控件分析 HtmlSelect 。
属性 AllowWhitespaceLiterals 设置为 false 允许始终忽略空格。 使用该方法 GetChildControlType 确定控件的 HtmlSelect 子控件的类型。
继承者说明
若要为 HtmlSelect 控件创建自定义控件生成器，需要从此类继承。
构造函数
| HtmlSelectBuilder() |
初始化 HtmlSelectBuilder 类的新实例。 |