Html32TextWriter クラス

定義

public ref class Html32TextWriter : System::Web::UI::HtmlTextWriter

public class Html32TextWriter : System.Web.UI.HtmlTextWriter

type Html32TextWriter = class
    inherit HtmlTextWriter

Public Class Html32TextWriter
Inherits HtmlTextWriter

継承

Object

MarshalByRefObject

TextWriter

HtmlTextWriter

Html32TextWriter

派生

System.Web.UI.ChtmlTextWriter

例

次のコード例では、Html32TextWriter クラスから派生した CustomHtml32TextWriterという名前のクラスを使用する方法を示します。 CustomHtml32TextWriter は、HtmlTextWriter クラスによって確立されたパターンに従う 2 つのコンストラクターを作成し、RenderBeforeContent、RenderAfterContent、RenderBeforeTag、および RenderAfterTag メソッドをオーバーライドします。

using System.IO;
using System.Web.UI;

namespace Examples.AspNet
{
    public class CustomHtml32TextWriter : Html32TextWriter
    {
        // Create a constructor for the class
        // that takes a TextWriter as a parameter.
        public CustomHtml32TextWriter(TextWriter writer) 
            : this(writer, DefaultTabString) 
        {
        }

        // Create a constructor for the class that takes
        // a TextWriter and a string as parameters.
        public CustomHtml32TextWriter(TextWriter writer, String tabString) 
            : base(writer, tabString)
        {
        }
        
        // Override the RenderBeforeContent method to render
        // styles before rendering the content of a <th> element.
        protected override string RenderBeforeContent()
        {
            // Check the TagKey property. If its value is
            // HtmlTextWriterTag.TH, check the value of the 
            // SupportsBold property. If true, return the
            // opening tag of a <b> element; otherwise, render
            // the opening tag of a <font> element with a color
            // attribute set to the hexadecimal value for red.
            if (TagKey == HtmlTextWriterTag.Th)
            {
                if (SupportsBold)
                    return "<b>";
                else
                    return "<font color=\"FF0000\">";
            }

            // Check whether the element being rendered
            // is an <H4> element. If it is, check the 
            // value of the SupportsItalic property.
            // If true, render the opening tag of the <i> element
            // prior to the <H4> element's content; otherwise, 
            // render the opening tag of a <font> element 
            // with a color attribute set to the hexadecimal
            // value for navy blue.
            if (TagKey == HtmlTextWriterTag.H4)
            {
                if (SupportsItalic)
                    return "<i>";
                else
                    return "<font color=\"000080\">";
            }
            // Call the base method.
            return base.RenderBeforeContent();
        }

        // Override the RenderAfterContent method to close
        // styles opened during the call to the RenderBeforeContent
        // method.
        protected override string RenderAfterContent()
        {
            // Check whether the element being rendered is a <th> element.
            // If so, and the requesting device supports bold formatting,
            // render the closing tag of the <b> element. If not,
            // render the closing tag of the <font> element.
            if (TagKey == HtmlTextWriterTag.Th)
            {
                if (SupportsBold)
                    return "</b>";
                else
                    return "</font>";
            }

            // Check whether the element being rendered is an <H4>.
            // element. If so, and the requesting device supports italic
            // formatting, render the closing tag of the <i> element.
            // If not, render the closing tag of the <font> element.
            if (TagKey == HtmlTextWriterTag.H4)
            {
                if (SupportsItalic)
                    return "</i>";
                else
                    return "</font>";
            }
            // Call the base method
            return base.RenderAfterContent();
        }

        // Override the RenderBeforeTag method to render the
        // opening tag of a <small> element to modify the text size of 
        // any <a> elements that this writer encounters.
        protected override string RenderBeforeTag()
        {
            // Check whether the element being rendered is an 
            // <a> element. If so, render the opening tag
            // of the <small> element; otherwise, call the base method.
            if (TagKey == HtmlTextWriterTag.A)
                return "<small>";
            return base.RenderBeforeTag();
        }

        // Override the RenderAfterTag method to render
        // close any elements opened in the RenderBeforeTag
        // method call.
        protected override string RenderAfterTag()
        {
            // Check whether the element being rendered is an
            // <a> element. If so, render the closing tag of the
            // <small> element; otherwise, call the base method.
            if (TagKey == HtmlTextWriterTag.A)
                return "</small>";
            return base.RenderAfterTag();
        }
    }
}

' Create a custom HtmlTextWriter class that overrides 
' the RenderBeforeContent and RenderAfterContent methods.
Imports System.IO
Imports System.Web.UI

Namespace Examples.AspNet


   Public Class CustomHtml32TextWriter
      Inherits Html32TextWriter

        ' Create a constructor for the class
        ' that takes a TextWriter as a parameter.
        Public Sub New(ByVal writer As TextWriter)
            Me.New(writer, DefaultTabString)
        End Sub

        ' Create a constructor for the class that takes
        ' a TextWriter and a string as parameters. 
        Public Sub New(ByVal writer As TextWriter, ByVal tabString As String)
            MyBase.New(writer, tabString)
        End Sub

        ' Override the RenderBeforeContent method to render
        ' styles before rendering the content of a <th> element.
        Protected Overrides Function RenderBeforeContent() As String
            ' Check the TagKey property. If its value is
            ' HtmlTextWriterTag.TH, check the value of the 
            ' SupportsBold property. If true, return the
            ' opening tag of a <b> element; otherwise, render
            ' the opening tag of a <font> element with a color
            ' attribute set to the hexadecimal value for red.
            If TagKey = HtmlTextWriterTag.Th Then
                If (SupportsBold) Then
                    Return "<b>"
                Else
                    Return "<font color=""FF0000"">"
                End If
            End If

            ' Check whether the element being rendered
            ' is an <H4> element. If it is, check the 
            ' value of the SupportsItalic property.
            ' If true, render the opening tag of the <i> element
            ' prior to the <H4> element's content; otherwise, 
            ' render the opening tag of a <font> element 
            ' with a color attribute set to the hexadecimal
            ' value for navy blue.
            If TagKey = HtmlTextWriterTag.H4 Then
                If (SupportsItalic) Then
                    Return "<i>"
                Else
                    Return "<font color=""000080"">"
                End If
            End If
            ' Call the base method.
            Return MyBase.RenderBeforeContent()
        End Function

        ' Override the RenderAfterContent method to close
        ' styles opened during the call to the RenderBeforeContent
        ' method.
        Protected Overrides Function RenderAfterContent() As String

            ' Check whether the element being rendered is a <th> element.
            ' If so, and the requesting device supports bold formatting,
            ' render the closing tag of the <b> element. If not,
            ' render the closing tag of the <font> element.
            If TagKey = HtmlTextWriterTag.Th Then
                If SupportsBold Then
                    Return "</b>"
                Else
                    Return "</font>"
                End If
            End If

            ' Check whether the element being rendered is an <H4>.
            ' element. If so, and the requesting device supports italic
            ' formatting, render the closing tag of the <i> element.
            ' If not, render the closing tag of the <font> element.
            If TagKey = HtmlTextWriterTag.H4 Then
                If (SupportsItalic) Then
                    Return "</i>"
                Else
                    Return "</font>"
                End If
            End If
            ' Call the base method.
            Return MyBase.RenderAfterContent()
        End Function

        ' Override the RenderBeforeTag method to render the
        ' opening tag of a <small> element to modify the text size of 
        ' any <a> elements that this writer encounters.
        Protected Overrides Function RenderBeforeTag() As String
            ' Check whether the element being rendered is an 
            ' <a> element. If so, render the opening tag
            ' of the <small> element; otherwise, call the base method.
            If TagKey = HtmlTextWriterTag.A Then
                Return "<small>"
            End If
            Return MyBase.RenderBeforeTag()
        End Function

        ' Override the RenderAfterTag method to render
        ' close any elements opened in the RenderBeforeTag
        ' method call.
        Protected Overrides Function RenderAfterTag() As String
            ' Check whether the element being rendered is an
            ' <a> element. If so, render the closing tag of the
            ' <small> element; otherwise, call the base method.
            If TagKey = HtmlTextWriterTag.A Then
                Return "</small>"
            End If
            Return MyBase.RenderAfterTag()
        End Function
    End Class
End Namespace

注釈

Html32TextWriter クラスは、HtmlTextWriter クラスの代わりに使用できます。 HTML 4.0 スタイル属性を同等の HTML 3.2 タグと属性に変換します。 HTML テーブルを使用して、色やフォントなどの属性の伝達を標準化します。 ASP.NET は、HttpBrowserCapabilities クラスの TagWriter プロパティを確認することで、HTML 3.2 以前のブラウザーでこのクラスを自動的に使用します。 HTML 3.2 マークアップを使用するデバイスを対象とするカスタム ページまたはコントロール アダプターを作成しない限り、Html32TextWriter クラスのインスタンスを明示的に作成する必要はありません。

ページおよびコントロールのレンダリングのカスタマイズの詳細については、「チュートリアル: カスタム Web サーバー コントロールの開発と使用」を参照してください。

コンストラクター

フィールド

プロパティ

メソッド

明示的なインターフェイスの実装

適用対象

こちらもご覧ください

• HtmlTextWriter
• チュートリアル: カスタム サーバー コントロール の開発と使用