共用方式為

HtmlTextWriter.FilterAttributes 方法

  • 參考

定義

命名空間:
System.Web.UI
組件:
System.Web.dll

移除網頁或 Web 伺服器控制項的所有屬性上的所有標記和樣式屬性。

protected:
 virtual void FilterAttributes();
protected virtual void FilterAttributes ();
abstract member FilterAttributes : unit -> unit
override this.FilterAttributes : unit -> unit
Protected Overridable Sub FilterAttributes ()

範例

下列程式碼範例示範如何使用衍生自 類別的 HtmlTextWriter 自訂類別來覆寫 FilterAttributes 方法。 呼叫時，覆寫會 FilterAttributes 檢查文字寫入器是否轉譯任何 <label> 或 <a> 專案：

  • <label>如果正在轉譯專案，此方法會 FilterAttributes 檢查屬性是否 style 在專案上呈現，如果不是，則會建立 style 屬性，並將它設定為 color: blue 。

  • <a>如果正在轉譯專案， FilterAttributes 方法會判斷是否包含屬性，如果不包含 href ，則會將 加入 href 至 URL http://www.cohowinery.com 。

// Override the FilterAttributes method to check whether 
// <label> and <anchor> elements contain specific attributes. 
virtual void FilterAttributes() override
{
   // If the <label> element is rendered and a style
   // attribute is not defined, add a style attribute 
   // and set its value to blue.
   if ( TagKey == HtmlTextWriterTag::Label )
   {
      if (  !IsAttributeDefined( HtmlTextWriterAttribute::Style ) )
      {
         AddAttribute( "style", EncodeAttributeValue( "color:blue", true ) );
         Write( NewLine );
         Indent = 3;
         OutputTabs();
      }
   }

   // If an <anchor> element is rendered and an href
   // attribute has not been defined, call the AddAttribute
   // method to add an href attribute
   // and set it to http://www.cohowinery.com.
   // Use the EncodeUrl method to convert any spaces to %20.
   if ( TagKey == HtmlTextWriterTag::A )
   {
      if (  !IsAttributeDefined( HtmlTextWriterAttribute::Href ) )
      {
         AddAttribute( "href", EncodeUrl( "http://www.cohowinery.com" ) );
      }
   }

   // Call the FilterAttributes method of the base class.
   __super::FilterAttributes();
}

// Override the FilterAttributes method to check whether 
// <label> and <anchor> elements contain specific attributes.      
protected override void FilterAttributes()
{
    // If the <label> element is rendered and a style
    // attribute is not defined, add a style attribute 
    // and set its value to blue.
    if (TagKey == HtmlTextWriterTag.Label)
    {
        if (!IsAttributeDefined(HtmlTextWriterAttribute.Style))
        {
            AddAttribute("style", EncodeAttributeValue("color:blue", true));
            Write(NewLine);
            Indent = 3;
            OutputTabs();
        }
    }

    // If an <anchor> element is rendered and an href
    // attribute has not been defined, call the AddAttribute
    // method to add an href attribute
    // and set it to http://www.cohowinery.com.
    // Use the EncodeUrl method to convert any spaces to %20.
    if (TagKey == HtmlTextWriterTag.A)
    {
        if (!IsAttributeDefined(HtmlTextWriterAttribute.Href))
        {
            AddAttribute("href", EncodeUrl("http://www.cohowinery.com"));
        }
    }
    // Call the FilterAttributes method of the base class.
    base.FilterAttributes();
}

' Override the FilterAttributes method to check whether 
' <label> and <anchor> elements contain specific attributes.   
Protected Overrides Sub FilterAttributes()

    ' If the <label> element is rendered and a style
    ' attribute is not defined, add a style attribute 
    ' and set its value to blue.
    If TagKey = HtmlTextWriterTag.Label Then
        If Not IsAttributeDefined(HtmlTextWriterAttribute.Style) Then
            AddAttribute("style", EncodeAttributeValue("color:blue", True))
            Write(NewLine)
            Indent = 3
            OutputTabs()
        End If
    End If
    ' If an <anchor> element is rendered and an href
    ' attribute has not been defined, call the AddAttribute
    ' method to add an href attribute
    ' and set it to http://www.cohowinery.com.
    ' Use the EncodeUrl method to convert any spaces to %20.
    If TagKey = HtmlTextWriterTag.A Then
        If Not IsAttributeDefined(HtmlTextWriterAttribute.Href) Then
            AddAttribute("href", EncodeUrl("http://www.cohowinery.com"))
        End If
    End If

    ' Call the FilterAttributes method of the base class.
    MyBase.FilterAttributes()
End Sub

備註

在標記專案上轉譯屬性之前，會 FilterAttributes 呼叫 方法。 接著，方法 FilterAttributes 會針對每個屬性和樣式呼叫 OnAttributeRender 和 OnStyleAttributeRender 方法，以轉譯。

適用於

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