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CssStyleCollection.Add Method (HtmlTextWriterStyle, String)

Adds a style item to the CssStyleCollection collection of a control using the specified HtmlTextWriterStyle enumeration value and corresponding value.

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

public void Add(
	HtmlTextWriterStyle key,
	string value


Type: System.Web.UI.HtmlTextWriterStyle
The HtmlTextWriterStyle enumeration value to add to the collection.
Type: System.String
The value of the style attribute to add to the collection.

If the style item to add exists in the HtmlTextWriterStyle enumeration, use this Add overload of the Add method rather than the overload that does not take an HtmlTextWriterStyle parameter.

The following code example demonstrates how to use both overloads of the Add method to add a cascading style sheet to an HtmlSelect, HtmlInputSubmit, and a Label control programmatically.

<%@ Page Language="C#" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "">

<script runat="server">

  protected void SubmitBtn_Click(object sender, EventArgs e)
    SubmitBtn.Style.Add("letter-spacing", "10px");
    FirstSelect.Style.Add(HtmlTextWriterStyle.Color, FirstSelect.Items[FirstSelect.SelectedIndex].Value.ToString());
    Message.Style.Add(HtmlTextWriterStyle.Color, FirstSelect.Items[FirstSelect.SelectedIndex].Value.ToString());
    Message.Text = "The select style is: " + FirstSelect.Style.Value;

<html xmlns="" >
<head runat="server">
    <title>CssStyleCollection Add</title>
    <form id="form1" runat="server">
    Select a color and then click submit.
    <br />
    <select id="FirstSelect" 
            style="font: 10pt verdana;color:black;" 
        <option value="black">black</option>
        <option value="red">red</option>
        <option value="blue">blue</option>
        <option value="green">green</option>
    <input id="SubmitBtn" 
           runat="server" /><br/>
    <br />
    <asp:Label id="Message"

.NET Framework

Supported in: 4, 3.5, 3.0, 2.0

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

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