HtmlTextWriter.RenderBeforeTag Método

Definição

Grava qualquer texto ou espaçamento que ocorre antes da marca de abertura de um elemento de marcação.Writes any text or spacing that occurs before the opening tag of a markup element.

protected:
 virtual System::String ^ RenderBeforeTag();
protected virtual string RenderBeforeTag ();
abstract member RenderBeforeTag : unit -> string
override this.RenderBeforeTag : unit -> string
Protected Overridable Function RenderBeforeTag () As String

Retornos

String

O texto ou espaçamento para gravar antes da marca de abertura do elemento de marcação.The text or spacing to write before the markup element opening tag. Se não for substituído, será null.If not overridden, null.

Exemplos

O exemplo de código a seguir mostra como substituir o RenderBeforeTag método para determinar se uma classe derivada da HtmlTextWriter classe está prestes a renderizar um <label> elemento.The following code example shows how to override the RenderBeforeTag method to determine whether a class that is derived from the HtmlTextWriter class is about to render a <label> element. Nesse caso, a RenderBeforeTag substituição insere a marca de abertura de um <font> elemento imediatamente antes do <label> elemento.If so, the RenderBeforeTag override inserts the opening tag of a <font> element immediately before the <label> element. Se não estiver renderizando um <label> elemento, o RenderBeforeTag método base será usado.If it is not rendering a <label> element, the RenderBeforeTag base method is used.

// Override the RenderBeforeTag method to add the
// opening tag of a Font element before the
// opening tag of any Label elements rendered by this
// custom markup writer.
virtual String^ RenderBeforeTag() override
{
   // Compare the TagName property value to the
   // String* label to determine whether the element to
   // be rendered is a Label. If it is a Label,
   // the opening tag of the Font element, with a Color
   // style attribute set to red, is added before
   // the Label.
   if ( String::Compare( TagName, "label" ) == 0 )
   {
      return "<font color=\"red\">";
   }
   // If a Label is not being rendered, use
   // the base RenderBeforeTag method.
   else
   {
      return __super::RenderBeforeTag();
   }
}
// Override the RenderBeforeTag method to add the 
// opening tag of a Font element before the 
// opening tag of any Label elements rendered by this 
// custom markup writer. 
protected override string RenderBeforeTag()
{
    // Compare the TagName property value to the
    // string label to determine whether the element to 
    // be rendered is a Label. If it is a Label,
    // the opening tag of the Font element, with a Color
    // style attribute set to red, is added before
    // the Label.
    if (String.Compare(TagName, "label") == 0)
    {
        return "<font color=\"red\">";
    }
    // If a Label is not being rendered, use 
        // the base RenderBeforeTag method.
    else
    {
        return base.RenderBeforeTag();
    }
}
' Override the RenderBeforeTag method to add the 
' opening tag of a Font element before the 
' opening tag of any Label elements rendered by this 
' custom markup writer. 
Protected Overrides Function RenderBeforeTag() As String
    ' Compare the TagName property value to the
    ' string label to determine whether the element to 
    ' be rendered is a Label. If it is a Label,
    ' the opening tag of the Font element, with a Color
    ' style attribute set to red, is added before
    ' the Label.
    If String.Compare(TagName, "label") = 0 Then
        Return "<font color=""red"">"
        ' If a Label is not being rendered, use 
        ' the base RenderBeforeTag method.
    Else
        Return MyBase.RenderBeforeTag()
    End If
End Function 'RenderBeforeTag

Comentários

O RenderBeforeTag método pode ser útil se você quiser renderizar marcas de abertura adicionais antes da marca de abertura do elemento pretendido.The RenderBeforeTag method can be useful if you want to render additional opening tags before the opening tag of the intended element.

Notas aos Herdeiros

A HtmlTextWriter implementação da classe do RenderBeforeTag() método retorna null .The HtmlTextWriter class implementation of the RenderBeforeTag() method returns null. Substituir RenderBeforeTag() se você quiser gravar o texto ou o espaçamento à frente da marca de abertura do elemento.Override RenderBeforeTag() if you want to write text or spacing ahead of the element opening tag.

Aplica-se a

Confira também