how to apply themes at runtime?

I find this link vey useful :
http://www.codeproject.com/Articles/18300/How-to-change-page-theme-in-asp-net-2-0-dynamicall

I added themes : As White , Yellow and Red In my Project .

To add theme :

<asp:button runat="server" xmlns:asp="#unknown">
  BackColor="White" 
  ForeColor="Black" 
  Font-Name="Times New Roman" 
  Font-Size="12px" />


<asp:button runat="server">
  BackColor="Red" 
  ForeColor="Green" 
  Font-Name="Arial Black" 
  Font-Size="12px" />

<asp:button runat="server">
  BackColor="Yellow" 
  ForeColor="Orange" 
  Font-Name="Comic Sans MS" 
  Font-Size="12px" />



</asp:button></asp:button></asp:button>

I have taken two buttons for Yellow and Red Theme and a label to Display message . Code is as below

<pre lang="HTML">
<asp:button id="btnYellowTheme" runat="server" text="Yellow Theme" style="position :absolute ; left: 76px; top: 74px;" onclick="btnYellowTheme_Click" xmlns:asp="#unknown" />       
<asp:button id="btnRedTheme" runat="server" text="Red Theme" style="position :absolute ; left: 225px; top: 74px;" height="24px" onclick="btnRedTheme_Click" xmlns:asp="#unknown" />       
<asp:label id="lblDisplay" runat="server" text="" style="position :absolute; left: 135px; top: 34px;" xmlns:asp="#unknown"></asp:label>

For Coding Part , to apply theme dynamically :

public partial class _Default : System.Web.UI.Page 
{

    string thmName; 
    protected void Page_Load(object sender, EventArgs e)
    {
      
    }
    protected void Page_PreInit(Object sender, EventArgs e)
    {
        thmName = (string)Session["ThemeName"];
        if (thmName != null)
        {
            Page.Theme = thmName;
            lblDisplay.Text = "You have applied Theme :" + (string)Session ["ThemeName"];
        }
        else
        {
            thmName = "White";
            Page.Theme = thmName;
            lblDisplay.Text = "This is default White Theme";
        }
    }
    protected void btnYellowTheme_Click(object sender, EventArgs e)
    {
        thmName = "Yellow";
        Session["ThemeName"] = thmName;
        Session["ThemeName"] = "Yellow";
        Server.Transfer(Request.FilePath);  
    }
    protected void btnRedTheme_Click(object sender, EventArgs e)
    {
        thmName = "Red";
        Session["ThemeName"] = thmName;
        Response.Redirect("Default.aspx");
        Session["ThemeName"] = "Red";
        Server.Transfer(Request.FilePath);
    }
}

<pre lang="text">
 
Thank You 

see this link it will help you
http://www.dotnetstuff.co.cc/2012/01/theame-settings-in-aspnet.html[^]

Hi,

Please check the following link.

Style Sheet Switcher[^]

Thanks,
Imdadhusen

This link may help you
http://www.planet-source-code.com/vb/scripts/ShowCode.asp?txtCodeId=9532&lngWId=4</a>[^]
Dynamic Themes in ASP.NET 2.0 (C#)[^]

Here is a Great Step by Step Tutorial on Skins and Themes in ASP.NET

http://msdn.microsoft.com/en-us/library/ykzx33wh.aspx[^]

In a handler for the page's PreInit method, set the page's Theme property. such as:

protected void Page_PreInit(object sender, EventArgs e)
{   
            Page.Theme = "BlueTheme";            
    
}

or as per your requirement try as :

In the designer source add a dropdown as :

<asp:DropDownList ID="Themes" runat="server" AutoPostBack="True">
        <asp:ListItem Selected="True">Default</asp:ListItem>
            <asp:ListItem>SmokeAndGlass</asp:ListItem>
            <asp:ListItem>UglyRed</asp:ListItem>
        <asp:ListItem>SkyHigh</asp:ListItem>
        <asp:ListItem>BasicBlue</asp:ListItem>
        </asp:DropDownList>

In a handler for the page's PreInit method, set the Theme .

protected void Page_PreInit(object sender, EventArgs e)
    
    {
        string theme = "";
        if (Page.Request.Form.Count > 0)
        {
            theme = Page.Request["Themes"].ToString();
            if (theme == "Default")
            {
                theme = "";
            }
        }
        this.Theme = theme;
    }     
    
}