L'exemple de code suivant montre comment substituer la méthode Render d'un contrôle personnalisé dérivé de la classe Control. L'exemple de code suivant montre comment utiliser les divers champs, propriétés et méthodes HtmlTextWriter.
' Overrides the Render method to write a <span> element
' that applies styles and attributes.
Protected Overrides Sub Render(ByVal writer As HtmlTextWriter)
' Set attributes and values along with attributes and styles
' attribute defined for a <span> element.
writer.AddAttribute(HtmlTextWriterAttribute.Onclick, "alert('Hello');")
writer.AddAttribute("CustomAttribute", "CustomAttributeValue")
writer.AddStyleAttribute(HtmlTextWriterStyle.Color, "Red")
writer.AddStyleAttribute("CustomStyle", "CustomStyleValue")
writer.RenderBeginTag(HtmlTextWriterTag.Span)
' Create a space and indent the markup inside the
' <span> element.
writer.WriteLine()
writer.Indent += 1
writer.Write("Hello")
writer.WriteLine()
' Controls the encoding of markup attributes
' for an <img> element. Simple known values
' do not need encoding.
writer.AddAttribute(HtmlTextWriterAttribute.Alt, _
"Encoding, ""Required""", _
True)
writer.AddAttribute("myattribute", _
"No "encoding " required", _
False)
writer.RenderBeginTag(HtmlTextWriterTag.Img)
writer.RenderEndTag()
writer.WriteLine()
' Create a non-standard markup element.
writer.RenderBeginTag("Mytag")
writer.Write("Contents of MyTag")
writer.RenderEndTag()
writer.WriteLine()
' Create a manually rendered <img> element
' that contains an alt attribute.
writer.WriteBeginTag("img")
writer.WriteAttribute("alt", "A custom image.")
writer.Write(HtmlTextWriter.TagRightChar)
writer.WriteEndTag("img")
writer.WriteLine()
writer.Indent -= 1
writer.RenderEndTag()
End Sub 'Render
// Overrides the Render method to write a <span> element
// that applies styles and attributes.
protected override void Render(HtmlTextWriter writer)
{
// Set attributes and values along with attributes and styles
// attribute defined for a <span> element.
writer.AddAttribute(HtmlTextWriterAttribute.Onclick, "alert('Hello');");
writer.AddAttribute("CustomAttribute", "CustomAttributeValue");
writer.AddStyleAttribute(HtmlTextWriterStyle.Color, "Red");
writer.AddStyleAttribute("Customstyle", "CustomStyleValue");
writer.RenderBeginTag(HtmlTextWriterTag.Span);
// Create a space and indent the markup inside the
// <span> element.
writer.WriteLine();
writer.Indent++;
writer.Write("Hello");
writer.WriteLine();
// Controls the encoding of markup attributes
// for an <img> element. Simple known values
// do not need encoding.
writer.AddAttribute(HtmlTextWriterAttribute.Alt,
"Encoding, \"Required\"",
true);
writer.AddAttribute("myattribute",
"No "encoding " required",
false);
writer.RenderBeginTag(HtmlTextWriterTag.Img);
writer.RenderEndTag();
writer.WriteLine();
// Create a non-standard markup element.
writer.RenderBeginTag("MyTag");
writer.Write("Contents of MyTag");
writer.RenderEndTag();
writer.WriteLine();
// Create a manually rendered <img> element
// that contains an alt attribute.
writer.WriteBeginTag("img");
writer.WriteAttribute("alt", "A custom image.");
writer.Write(HtmlTextWriter.TagRightChar);
writer.WriteEndTag("img");
writer.WriteLine();
writer.Indent--;
writer.RenderEndTag();
}