Handle Server-Side Errors in the Report Designer for ASP.NET Core
- 5 minutes to read
This document describes how to handle Report Designer server-side errors. It also explains how to display detailed error information instead of a generic “Internal Server Error” message.
Tip
Online Example: How to handle server-side errors in web reporting controls
The following table lists the classes and interfaces that allow you to process errors in the Report Designer.
Control | Class (Default Implementation) | Interface |
|---|---|---|
Report Designer | ||
Built-in Document Viewer | ||
Handle Unknown Exceptions
The Report Designer displays the “Internal Server Error” message in a browser for all exceptions except FaultException and DocumentCreationException. For instance, such unknown exceptions occur when you try to open a broken report layout or a file that does not exist.
All the classes listed above provide the GetUnknownExceptionMessage method that is called whenever an unknown exception is raised. You can override this method to return a custom text or the Exception.Message property’s value as shown in the following example.
using System;
using System.IO;
using DevExpress.XtraReports.Web.ReportDesigner.Services;
using DevExpress.XtraReports.Web.WebDocumentViewer;
using DevExpress.XtraReports.Web.QueryBuilder.Services;
public class CustomReportDesignerExceptionHandler : ReportDesignerExceptionHandler {
public override string GetUnknownExceptionMessage(Exception ex) {
if (ex is FileNotFoundException) {
#if DEBUG
return ex.Message;
#else
return "File is not found.";
#endif
}
return ex.GetType().Name + " occurred. See the log file for more details.";
}
}
}
public class CustomWebDocumentViewerExceptionHandler : WebDocumentViewerExceptionHandler {
public override string GetUnknownExceptionMessage(Exception ex) {
return ex.GetType().Name + " occurred. See the log file for more details.";
}
}
public class CustomQueryBuilderExceptionHandler : QueryBuilderExceptionHandler {
public override string GetUnknownExceptionMessage(Exception ex) {
return ex.GetType().Name + " occurred. See the log file for more details.";
}
}
Handle FaultException
The Report Designer shows the Exception.Message property’s value when FaultException occurs (for instance, when you pass an invalid URL to a report storage).
Use the GetFaultExceptionMessage method to return a custom message for these exceptions as demonstrated below.
using System;
using System.ServiceModel;
using DevExpress.XtraReports.Web.ReportDesigner.Services;
public class CustomReportDesignerExceptionHandler : ReportDesignerExceptionHandler {
public override string GetFaultExceptionMessage(FaultException ex) {
return "FaultException occurred: " + faultException.Message + ".";
}
}
Handle DocumentCreationException
The Document Viewer displays the Exception.Message property’s value for DocumentCreationException. This exception can occur when you switch to the Report Designer’s built-in Document Viewer and a report document is being generated (for instance, an error arises in the BeforePrint or AfterPrint event).
You can override the WebDocumentViewerExceptionHandler.GetDocumentCreationExceptionMessage method to return a custom text as shown below.
using DevExpress.XtraReports.Web.WebDocumentViewer;
public class CustomWebDocumentViewerExceptionHandler : WebDocumentViewerExceptionHandler {
public override string GetDocumentCreationExceptionMessage(DocumentCreationException ex) {
return "An exception occurred while document creation.";
}
}
Handle All Exceptions
You can implement the following interfaces to handle all server-side errors independently from their types.
Each interface contains the GetExceptionMessage method that is called when any server-side error occurs.
The code snippet below demonstrates how to implement these interfaces and return custom text.
using System;
using System.IO;
using DevExpress.XtraReports.Web.QueryBuilder.Services;
using DevExpress.XtraReports.Web.ReportDesigner.Services;
using DevExpress.XtraReports.Web.WebDocumentViewer;
public class CustomExceptionHandler : IReportDesignerExceptionHandler,
IWebDocumentViewerExceptionHandler, IQueryBuilderExceptionHandler {
public string GetExceptionMessage(Exception ex) {
return ex.GetType().Name + " occurred. See the log file for more details.";
}
}
Register Exception Handlers
To register the implemented exception handlers, use the following static methods at the application’s startup.
- DefaultWebDocumentViewerContainer.Register
- DefaultReportDesignerContainer.Register
- DefaultQueryBuilderContainer.Register
void Application_Start(object sender, EventArgs e) {
// ...
DevExpress.XtraReports.Web.WebDocumentViewer.DefaultWebDocumentViewerContainer.
Register<IWebDocumentViewerExceptionHandler, CustomWebDocumentViewerExceptionHandler>();
DevExpress.XtraReports.Web.ReportDesigner.DefaultReportDesignerContainer.
Register<IReportDesignerExceptionHandler, CustomReportDesignerExceptionHandler>();
DevExpress.XtraReports.Web.QueryBuilder.DefaultQueryBuilderContainer.
Register<IQueryBuilderExceptionHandler, CustomQueryBuilderExceptionHandler>();
}