ASP.NET Web Forms - How to change themes on the fly

This example illustrates how to change themes on the fly.

Implementation Details

You can apply a theme to DevExpress ASP.NET Web Forms controls in the following ways:

Apply a Theme with the ASP.NET Mechanism

Specify a page's Page.Theme property in the Page.PreInit event handler.

C#
protected void Page_PreInit(object sender, EventArgs e) {  
    HttpCookie c = Request.Cookies["theme"];  
    Page.Theme = c == null ? "Aqua" : c.Value;  
}

Apply a Theme with the DevExpress Mechanism

Set the ASPxWebControl.GlobalTheme property to the theme name in the Page.PreInit event handler.

C#
protected void Page_PreInit(object sender, EventArgs e) {  
    HttpCookie c = Request.Cookies["theme"];  
    ASPxWebControl.GlobalTheme = c == null ? "Aqua" : c.Value;  
}

Documentation

More Examples

ASP.NET MVC - How to change themes on the fly

Example Code

Default2.aspx

ASPx
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default2.aspx.cs" Inherits="Default2" %>

<%@ Register Assembly="DevExpress.Web.v13.2, Version=13.2.15.0, Culture=neutral, PublicKeyToken=b88d1754d700e49a" Namespace="DevExpress.Web" TagPrefix="dx" %>



<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head id="Head1" runat="server">
    <title>How to change a page's theme dynamically</title>
</head>
<body>
    <form id="form1" runat="server">
    <table>
        <tr>
            <td>                
                <dx:ASPxGridView ID="ASPxGridView1" runat="server" AutoGenerateColumns="False" DataSourceID="dataSource"
                    KeyFieldName="CategoryID">
                    <Columns>
                        <dx:GridViewDataTextColumn FieldName="CategoryID" ReadOnly="True" VisibleIndex="0">
                            <EditFormSettings Visible="False" />
                        </dx:GridViewDataTextColumn>
                        <dx:GridViewDataTextColumn FieldName="CategoryName" VisibleIndex="1">
                        </dx:GridViewDataTextColumn>
                        <dx:GridViewDataTextColumn FieldName="Description" VisibleIndex="2">
                        </dx:GridViewDataTextColumn>
                    </Columns>
                </dx:ASPxGridView>
                &nbsp;<br />
                <dx:ASPxTextBox ID="ASPxTextBox1" runat="server" Width="170px">
                </dx:ASPxTextBox>
                <dx:ASPxButton ID="button" runat="server" Text="Button">
                </dx:ASPxButton>
            </td>
            <td valign="top">
                <dx:ASPxRadioButtonList ID="rbList" runat="server" AutoPostBack="True" SelectedIndex="0">
                    <ClientSideEvents SelectedIndexChanged="function(s, e) { ASPxClientUtils.SetCookie('theme', s.GetValue());}" />
                    <Items>
                        <dx:ListEditItem Selected="True" Text="Aqua" Value="Aqua" />
                        <dx:ListEditItem Text="DevEx" Value="DevEx" />
                        <dx:ListEditItem Text="SoftOrange" Value="SoftOrange" />
                        <dx:ListEditItem Text="Youthful" Value="Youthful" />
                    </Items>
                </dx:ASPxRadioButtonList>
                <asp:SqlDataSource ID="dataSource" runat="server" ConnectionString="Data Source=(local);Initial Catalog=Northwind;Integrated Security=True"
                    ProviderName="System.Data.SqlClient" SelectCommand="SELECT [CategoryID], [CategoryName], [Description] FROM [Categories]">
                </asp:SqlDataSource>
            </td>
        </tr>
    </table>
    </form>
</body>
</html>

Default2.aspx.cs(vb)

C#
VB.NET

C#
using System;
using System.Collections.Generic;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;

public partial class Default2 : System.Web.UI.Page {
    protected void Page_PreInit(object sender, EventArgs e) {
        HttpCookie c = Request.Cookies["theme"];
        Page.Theme = c == null ? "Aqua" : c.Value;

    }
    protected void Page_Load(object sender, EventArgs e) {
        HttpCookie c = Request.Cookies["theme"];
        if(!IsPostBack && (c != null))
            rbList.Value = c.Value;
    }
}

Visual Basic
Imports System
Imports System.Collections.Generic
Imports System.Web
Imports System.Web.UI
Imports System.Web.UI.WebControls

Partial Public Class Default2
    Inherits System.Web.UI.Page

    Protected Sub Page_PreInit(ByVal sender As Object, ByVal e As EventArgs)
        Dim c As HttpCookie = Request.Cookies("theme")
        Page.Theme = If(c Is Nothing, "Aqua", c.Value)

    End Sub
    Protected Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs)
        Dim c As HttpCookie = Request.Cookies("theme")
        If Not IsPostBack AndAlso (c IsNot Nothing) Then
            rbList.Value = c.Value
        End If
    End Sub
End Class

Default3.aspx

ASPx
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default3.aspx.cs" Inherits="Default3" %>

<%@ Register Assembly="DevExpress.Web.v13.2, Version=13.2.15.0, Culture=neutral, PublicKeyToken=b88d1754d700e49a" Namespace="DevExpress.Web" TagPrefix="dx" %>



<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head id="Head1" runat="server">
    <title>How to change a page's theme dynamically</title>
</head>
<body>
    <form id="form1" runat="server">
    <table>
        <tr>
            <td>
                <dx:ASPxGridView ID="ASPxGridView1" runat="server" AutoGenerateColumns="False" DataSourceID="dataSource"
                    KeyFieldName="CategoryID">
                    <Columns>
                        <dx:GridViewDataTextColumn FieldName="CategoryID" ReadOnly="True" VisibleIndex="0">
                            <EditFormSettings Visible="False" />
                        </dx:GridViewDataTextColumn>
                        <dx:GridViewDataTextColumn FieldName="CategoryName" VisibleIndex="1">
                        </dx:GridViewDataTextColumn>
                        <dx:GridViewDataTextColumn FieldName="Description" VisibleIndex="2">
                        </dx:GridViewDataTextColumn>
                    </Columns>
                </dx:ASPxGridView>
                &nbsp;<br />
                <dx:ASPxTextBox ID="ASPxTextBox1" runat="server" Width="170px">
                </dx:ASPxTextBox>
                <dx:ASPxButton ID="button" runat="server" Text="Button">
                </dx:ASPxButton>
            </td>
            <td valign="top">
                <dx:ASPxRadioButtonList ID="rbList" runat="server" AutoPostBack="True" SelectedIndex="0">
                    <ClientSideEvents SelectedIndexChanged="function(s, e) { ASPxClientUtils.SetCookie('theme', s.GetValue());}" />
                    <Items>
                        <dx:ListEditItem Selected="True" Text="Aqua" Value="Aqua" />
                        <dx:ListEditItem Text="DevEx" Value="DevEx" />
                        <dx:ListEditItem Text="SoftOrange" Value="SoftOrange" />
                        <dx:ListEditItem Text="Youthful" Value="Youthful" />
                    </Items>
                </dx:ASPxRadioButtonList>
                <asp:SqlDataSource ID="dataSource" runat="server" ConnectionString="Data Source=(local);Initial Catalog=Northwind;Integrated Security=True"
                    ProviderName="System.Data.SqlClient" SelectCommand="SELECT [CategoryID], [CategoryName], [Description] FROM [Categories]">
                </asp:SqlDataSource>
            </td>
        </tr>
    </table>
    </form>
</body>
</html>

Default3.aspx.cs(vb)

C#
VB.NET

C#
using DevExpress.Web;
using System;
using System.Collections.Generic;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;

public partial class Default3 : System.Web.UI.Page {
    protected void Page_PreInit(object sender, EventArgs e) {
        HttpCookie c = Request.Cookies["theme"];
        ASPxWebControl.GlobalTheme = c == null ? "Aqua" : c.Value;
    }
    protected void Page_Load(object sender, EventArgs e) {
        HttpCookie c = Request.Cookies["theme"];
        if(!IsPostBack && (c != null))
            rbList.Value = c.Value;
    }
}

Visual Basic
Imports DevExpress.Web
Imports System
Imports System.Collections.Generic
Imports System.Web
Imports System.Web.UI
Imports System.Web.UI.WebControls

Partial Public Class Default3
    Inherits System.Web.UI.Page

    Protected Sub Page_PreInit(ByVal sender As Object, ByVal e As EventArgs)
        Dim c As HttpCookie = Request.Cookies("theme")
        ASPxWebControl.GlobalTheme = If(c Is Nothing, "Aqua", c.Value)
    End Sub
    Protected Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs)
        Dim c As HttpCookie = Request.Cookies("theme")
        If Not IsPostBack AndAlso (c IsNot Nothing) Then
            rbList.Value = c.Value
        End If
    End Sub
End Class

DevExpress Support Team

last modified a year ago

Modified: November 7, 2023 7:34 AM

Platform: ASP.NET Web Forms

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