If you like using DevExpress controls in your traditional asp.net application and would like to continue using them inside SharePoint, here are few steps that you can take to “configure” your webapplication for this setup.
Step 1) Ensure that you do copy local to all devEx assemblies that you are using in the webpart project.
Step 2) Open web.config file for your web application. Mine was located here at “C:\inetpub\wwwroot\wss\VirtualDirectories\80”. Then under ConfigSection add a new group as below.
<sectionGroup name="devExpress">
<section name="compression" type="DevExpress.Web.ASPxClasses.CompressionConfigurationSection, DevExpress.Web.v10.2, Version=10.2.5.0, Culture=neutral, PublicKeyToken=b88d1754d700e49a" requirePermission="false" />
<section name="themes" type="DevExpress.Web.ASPxClasses.ThemesConfigurationSection, DevExpress.Web.v10.2, Version=10.2.5.0, Culture=neutral, PublicKeyToken=b88d1754d700e49a" requirePermission="false" />
<section name="errors" type="DevExpress.Web.ASPxClasses.ErrorsConfigurationSection, DevExpress.Web.v10.2, Version=10.2.5.0, Culture=neutral, PublicKeyToken=b88d1754d700e49a" requirePermission="false" />
</sectionGroup>
Step 3) Under assemblies section add the following lines.
<add assembly="DevExpress.Web.ASPxEditors.v10.2, Version=10.2.5.0, Culture=neutral, PublicKeyToken=B88D1754D700E49A" />
<add assembly="DevExpress.Web.v10.2, Version=10.2.5.0, Culture=neutral, PublicKeyToken=B88D1754D700E49A" />
<add assembly="DevExpress.Data.v10.2, Version=10.2.5.0, Culture=neutral, PublicKeyToken=B88D1754D700E49A" />
<add assembly="DevExpress.Web.ASPxGridView.v10.2, Version=10.2.5.0, Culture=neutral, PublicKeyToken=B88D1754D700E49A" />
Step 4) Under System.webserver –> Modules, add the following line.
<add name="ASPxHttpHandlerModule" type="DevExpress.Web.ASPxClasses.ASPxHttpHandlerModule, DevExpress.Web.v10.2, Version=10.2.5.0, Culture=neutral, PublicKeyToken=b88d1754d700e49a" />
Step 5) Finally, under httpmodules, add the following line.
<add name="ASPxHttpHandlerModule" type="DevExpress.Web.ASPxClasses.ASPxHttpHandlerModule, DevExpress.Web.v10.1, Version=10.1.4.0, Culture=neutral, PublicKeyToken=b88d1754d700e49a" />
Thats it, You should be good to go.