Troubleshooting

• Feb 06, 2024
• 3 minutes to read

This section describes common issues and steps you can follow to diagnose and resolve these issues. If the solutions listed here do not help, create a ticket in our Support Center.

To diagnose and collect a detailed information about the issue, see the instructions listed in the following topicS:

• Get Started (How to collect detailed information about the issue)
• KB Article: How to enable script debugging
• KB Article: How to determine the cause of an internal server error
• How to inspect CSS rules

Client-Side Issues

• The ‘X is undefined’ error occurs or extensions are rendered with incorrect styles
• Cannot access DevExpress ASP.NET MVC extensions on the client
• DevExpress MVC extensions do not work after the first callback
• The ‘ReferenceError: ‘X’ is not defined’ error message appears when the Control.Enabled property is set to false

Server-Side Issues

• The controller for ASPxUploadProgressHandlerPage.ashx was not found or does not implement IController
• Internal Error. Unable to find the X resource in the Y
• A primary key field specified using the KeyFieldName property is not found
• The ‘Key expression is undefined’ error occurs when you use GridViewExtension.BindToLINQ / GridViewExtension.BindToEF methods
• ‘The X has no access to path Y’ or ‘Access to the path X is denied’ (Image and File Extensions)
• Why redirect to another page or View does not work on AJAX requests
• Data binding directly to a store query (DbSet, DbQuery, DbSqlQuery, DbRawSqlQuery) is not supported
• An alert message with the HTML/JavaScript/CSS content appears when you use callback-aware extensions
• An extension with ‘X’ name is already rendered
• ‘System.Web.WebPages.Html.HtmlHelper’ does not contain a definition for ‘DevExpress’
• The call is ambiguous between the following methods or properties: ‘DevExpress.Web.Mvc.UI.HtmlHelperExtension.DevExpress<ModelType>’
• Cannot convert lambda expression to type X because it is not a delegate type

Installation and Update Issues

• Type ‘X’ exists in both assemblies / Type ‘X’ is ambiguous in namespace ‘Y’
• Could not load file or assembly ‘X’
• Cannot modify the Global Assembly Cache
• Could not load file or assembly System.Web.Mvc or one of its dependencies
• Inheritance security rules violated by type: ‘DevExpress.Web.Mvc.DevExpressEditorsBinder’. Derived types must either match the security accessibility of the base type or be less accessible.
• Why the ‘Insert DevExpress MVC Extension’ option can be missing in the DevExpress section of Visual Studio’s main menu and in the context menu in an MVC 5 project

Performance Issues

• How To: Improve View Rendering Speed

Grid-Related Issues

• Grid displays empty rows in database server mode

Themes-Related Issues

• []’Cannot find the X theme’ or ‘Theme X cannot be found in the application or global theme directories’ errors occur](/AspNetMvc/403776/troubleshooting/theme-related-issues/cannot-find-theme-application-or-globally)