HtmlTextWriter.IsStyleAttributeDefined Method (HtmlTextWriterStyle)


The .NET API Reference documentation has a new home. Visit the .NET API Browser on to see the new experience.

Determines whether the specified markup style attribute is rendered during the next call to the RenderBeginTag method.

Namespace:   System.Web.UI
Assembly:  System.Web (in System.Web.dll)

protected bool IsStyleAttributeDefined(
	HtmlTextWriterStyle key


Type: System.Web.UI.HtmlTextWriterStyle

The HtmlTextWriterStyle associated with the attribute.

Return Value

Type: System.Boolean

true if the attribute will be rendered during the next call to the RenderBeginTag method; otherwise, false.

To get the value that will be rendered with the specified style attribute, use the IsStyleAttributeDefined(HtmlTextWriterStyle, String) overload of the IsStyleAttributeDefined method.

The following code example shows how to check whether a <label> element is being rendered. If so, the IsStyleAttributeDefined method checks whether a Color style attribute has been defined on the element. If the Color attribute has not been defined, the AddStyleAttribute method defines the Color attribute and sets its value to red.

// If the markup element being rendered is a Label,
// render the opening tag of a Font element before it.
if (tagKey == HtmlTextWriterTag.Label)
    // Check whether a Color style attribute is 
    // included on the Label. If not, use the
    // AddStyleAttribute and GetStyleName methods to add one
    // and set its value to red.
    if (!IsStyleAttributeDefined(HtmlTextWriterStyle.Color))
        AddStyleAttribute(GetStyleName(HtmlTextWriterStyle.Color), "red");

.NET Framework
Available since 1.1
Return to top