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HtmlTextWriter.GetAttributeKey Method

Obtains the corresponding HtmlTextWriterAttribute enumeration value for the specified attribute.

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

protected HtmlTextWriterAttribute GetAttributeKey(
	string attrName
)

Parameters

attrName
Type: System.String

A string that contains the attribute for which to obtain the HtmlTextWriterAttribute.

Return Value

Type: System.Web.UI.HtmlTextWriterAttribute
The HtmlTextWriterAttribute enumeration value for the specified attribute; otherwise, an invalid HtmlTextWriterAttribute value if the attribute is not a member of the enumeration.

If attrName is null or an empty string (""), or cannot be found in the table of attribute names, the value -1, typed to an HtmlTextWriterAttribute object, is returned.

The following code example demonstrates how to use a class, derived from the HtmlTextWriter class, that overrides the RenderBeginTag method. The override checks whether tagKey is equal to the Font field, which indicates that a <font> markup element will be rendered. If so, the override calls the IsAttributeDefined method to find out whether the <font> element contains a Size attribute. If the IsAttributeDefined returns false, the AddAttribute method calls the GetAttributeKey method, which defines the Size and sets its value to 30pt.

// If the tagKey parameter is set to a <font> element 
// but a size attribute is not defined on the element, 
// the AddStyleAttribute method adds a size attribute 
// and sets it to 30 point.  
if (tagKey == HtmlTextWriterTag.Font)
{
    if (!IsAttributeDefined(HtmlTextWriterAttribute.Size))
    {
        AddAttribute(GetAttributeKey("size"), "30pt");
    }
}

.NET Framework

Supported in: 4.5, 4, 3.5, 3.0, 2.0, 1.1, 1.0

Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

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