HtmlTextWriter.GetStyleKey(String) Method

Definition

Namespace:

System.Web.UI

Assembly:

System.Web.dll

Obtains the HtmlTextWriterStyle enumeration value for the specified style.

protected:
 System::Web::UI::HtmlTextWriterStyle GetStyleKey(System::String ^ styleName);

protected System.Web.UI.HtmlTextWriterStyle GetStyleKey (string styleName);

member this.GetStyleKey : string -> System.Web.UI.HtmlTextWriterStyle

Protected Function GetStyleKey (styleName As String) As HtmlTextWriterStyle

Parameters

styleName

String

The style attribute for which to obtain the HtmlTextWriterStyle.

Returns

HtmlTextWriterStyle

The HtmlTextWriterStyle enumeration value corresponding to styleName.

Examples

The following code example demonstrates how to override the RenderBeginTag method in a class derived from the HtmlTextWriter class. The RenderBeginTag override determines whether a <label> markup will be rendered, and, if so, checks the element for a Color attribute. If a Color attribute has not been defined, the GetStyleKey method is used as the first parameter in a call to the AddStyleAttribute method to add a Color attribute to a <label> markup element and set the Color attribute to red.

// Override the RenderBeginTag method to check whether
// the tagKey parameter is set to a <label> element
// or a <font> element.   
virtual void RenderBeginTag( HtmlTextWriterTag tagKey ) override
{
   // If the tagKey parameter is set to a <label> element
   // but a color attribute is not defined on the element,
   // the AddStyleAttribute method adds a color attribute
   // and sets it to red.
   if ( tagKey == HtmlTextWriterTag::Label )
   {
      if (  !IsStyleAttributeDefined( HtmlTextWriterStyle::Color ) )
      {
         AddStyleAttribute( GetStyleKey( "color" ), "red" );
      }
   }

   // 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" );
      }
   }

   // Call the base class's RenderBeginTag method
   // to ensure that calling this custom markup writer
   // includes functionality for all other elements.
   __super::RenderBeginTag( tagKey );
}

// Override the RenderBeginTag method to check whether
// the tagKey parameter is set to a <label> element
// or a <font> element.
public override void RenderBeginTag(HtmlTextWriterTag tagKey)
{

    // If the tagKey parameter is set to a <label> element
    // but a color attribute is not defined on the element,
    // the AddStyleAttribute method adds a color attribute
    // and sets it to red.
    if (tagKey == HtmlTextWriterTag.Label)
    {
        if (!IsStyleAttributeDefined(HtmlTextWriterStyle.Color))
        {
            AddStyleAttribute(GetStyleKey("color"), "red");
        }
    }
    // 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");
        }
    }
    // Call the base class's RenderBeginTag method
    // to ensure that this custom MarkupTextWriter
    // includes functionality for all other markup elements.
    base.RenderBeginTag(tagKey);
}

' Override the RenderBeginTag method to check whether
' the tagKey parameter is set to a <label> element
' or a <font> element.   
Public Overloads Overrides Sub RenderBeginTag(ByVal tagKey As HtmlTextWriterTag)
    ' If the tagKey parameter is set to a <label> element
    ' but a color attribute is not defined on the element,
    ' the AddStyleAttribute method adds a color attribute
    ' and sets it to red.
    If tagKey = HtmlTextWriterTag.Label Then
        If Not IsStyleAttributeDefined(HtmlTextWriterStyle.Color) Then
            AddStyleAttribute(GetStyleKey("color"), "red")
        End If
    End If

    ' 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 Then
        If Not IsAttributeDefined(HtmlTextWriterAttribute.Size) Then
            AddAttribute(GetAttributeKey("size"), "30pt")
        End If
    End If

    ' Call the base class's RenderBeginTag method
    ' to ensure that this custom MarkupTextWriter
    ' includes functionality for all other markup elements.
    MyBase.RenderBeginTag(tagKey)
End Sub

Remarks

The GetStyleKey method returns the value -1 typed as a HtmlTextWriterStyle value, if styleName does not correspond to any HtmlTextWriterStyle enumeration value.

See also

• TextWriter
• HtmlTextWriterStyle
• AddStyleAttribute