Example T893871

Visible to All Users

Dashboard for MVC - How to handle errors

The following example demostrates two approaches on how to handle errors in the ASP.NET MVC Dashboard application:

How to specify custom text for internal Dashboard errors
How to throw a custom exception during a server-side processing and display the error in the Dashboard error toast

Both projects in this example override the OnException method. You can also handle the ASPxWebControl.CallbackError event to customize error text. See the following example for details about this approach: ASP.NET Web Forms Dashboard - How to handle errors

How to specify custom text for internal Dashboard errors

Files to Review

Global.asax.cs (VB: Global.asax.vb)
CustomDashboardController.cs (VB: CustomDashboardController.vb)
DashboardConfig.cs (VB: DashboardConfig.vb)
Index.cshtml VB: Index.vbhtml)

Description

The dashboard in this project contains invalid data connection. This example shows how to override the OnException method in a custom dashboard controller to specify custom text in the exception. The exception occurs when the controller tries to load data.

Create a custom dashboard controller and override the OnException method. You can specify the displayed text depending on whether the application is in development mode.
Specify the created custom controller's name in the view.
Use the created CustomDashboard controller when you map a dashboard route.

How to throw a custom exception during a server-side processing and display the error in the Dashboard error toast

Files to Review

Global.asax.cs (VB: Global.asax.vb)
DashboardConfig.cs (VB: DashboardConfig.vb)
CustomDashboardController.cs (VB: CustomDashboardController.vb)
Index.cshtml (VB: Index.vbhtml)

Description

This example shows how to throw a custom exception when a controller loads a dashboard and display this exception in the dashboard error toast. The example overrides the OnException method.

Create a custom dashboard controller and override the OnException method. You can specify the displayed text depending on whether the application is in development mode.
Specify the created custom controller's name in the view.
Use the created CustomDashboard controller when you map a dashboard route.
To throw an exception when the control loads a dashboard, create custom dashboard storage and override the LoadDashboard method.

Documentation

Handle and Log Server-Side Errors in ASP.NET MVC

More Examples

Example Code

MvcCustomTextForInternalDashboardErrors/Global.asax.cs(vb)

C#
VB.NET

C#
using DevExpress.DashboardCommon;
using DevExpress.DashboardWeb;
using DevExpress.DataAccess.ConnectionParameters;
using DevExpress.DataAccess.Sql;
using System.Web.Mvc;
using System.Web.Routing;

namespace MvcCustomTextForInternalDashboardErrors {
    public class MvcApplication : System.Web.HttpApplication
    {

        protected void Application_Start()
        {
            DashboardConfig.RegisterService(RouteTable.Routes);
            AreaRegistration.RegisterAllAreas();
            RouteConfig.RegisterRoutes(RouteTable.Routes);
            ControllerBuilder.Current.SetControllerFactory(typeof(RestrictedControllerFactory));

            DataSourceInMemoryStorage dataSourceStrorage = new DataSourceInMemoryStorage();

            DashboardSqlDataSource sql = new DashboardSqlDataSource("sql", "sqlConn");
            sql.Queries.Add(SelectQueryFluentBuilder.AddTable("Products").SelectAllColumns().Build("query"));
            dataSourceStrorage.RegisterDataSource(sql.SaveToXml());

            DashboardConfigurator.Default.SetDashboardStorage(new DashboardFileStorage(Server.MapPath("~/App_Data/Dashboards")));
            DashboardConfigurator.Default.SetDataSourceStorage(dataSourceStrorage);
            DashboardConfigurator.Default.ConfigureDataConnection += ASPxDashboard1_ConfigureDataConnection;
        }

        void ASPxDashboard1_ConfigureDataConnection(object sender, ConfigureDataConnectionWebEventArgs e) {
            // Invalid connection parameters:
            switch (e.ConnectionName) {
                case "sqlConn":
                    e.ConnectionParameters = new MsSqlConnectionParameters(@"localhost", "Northwind123", null, null, MsSqlAuthorizationType.Windows);
                    break;
            }
        }
    }
}

Visual Basic
Imports Microsoft.VisualBasic
Imports DevExpress.DashboardCommon
Imports DevExpress.DashboardWeb
Imports DevExpress.DataAccess.ConnectionParameters
Imports DevExpress.DataAccess.Sql
Imports System.Web.Mvc
Imports System.Web.Routing

Namespace MvcCustomTextForInternalDashboardErrors
    Public Class MvcApplication
        Inherits System.Web.HttpApplication

        Protected Sub Application_Start()
            DashboardConfig.RegisterService(RouteTable.Routes)
            AreaRegistration.RegisterAllAreas()
            RouteConfig.RegisterRoutes(RouteTable.Routes)
            ControllerBuilder.Current.SetControllerFactory(GetType(RestrictedControllerFactory))

            Dim dataSourceStrorage As New DataSourceInMemoryStorage()

            Dim sql As New DashboardSqlDataSource("sql", "sqlConn")
            sql.Queries.Add(SelectQueryFluentBuilder.AddTable("Products").SelectAllColumns().Build("query"))
            dataSourceStrorage.RegisterDataSource(sql.SaveToXml())

            DashboardConfigurator.Default.SetDashboardStorage(New DashboardFileStorage(Server.MapPath("~/App_Data/Dashboards")))
            DashboardConfigurator.Default.SetDataSourceStorage(dataSourceStrorage)
            AddHandler DashboardConfigurator.Default.ConfigureDataConnection, AddressOf ASPxDashboard1_ConfigureDataConnection
        End Sub

        Private Sub ASPxDashboard1_ConfigureDataConnection(ByVal sender As Object, ByVal e As ConfigureDataConnectionWebEventArgs)
            ' Invalid connection parameters:
            Select Case e.ConnectionName
                Case "sqlConn"
                    e.ConnectionParameters = New MsSqlConnectionParameters("localhost", "Northwind123", Nothing, Nothing, MsSqlAuthorizationType.Windows)
            End Select
        End Sub
    End Class
End Namespace

MvcCustomTextForInternalDashboardErrors/Controllers/CustomDashboardController.cs(vb)

C#
VB.NET

C#
using DevExpress.DashboardWeb.Mvc;
using System;
using System.Net;
using System.Web.Mvc;

namespace MvcCustomTextForInternalDashboardErrors {
    public class CustomDashboardController : DashboardController
    {
        protected override void OnException(ExceptionContext context) {
            var exception = context.Exception;
            if(exception != null && context.HttpContext != null) {
                var response = context.HttpContext.Response;
                response.StatusCode = (int)HttpStatusCode.BadRequest;

                response.ContentType = "application/json";
                // The 'mode' attribute in the 'customErrors' section of the Web.config file specifies whether an application is in development mode.
                bool isCustomErrorsEnabled = System.Web.HttpContext.Current != null ? System.Web.HttpContext.Current.IsCustomErrorEnabled : true;

                response.Write(GetJson(isCustomErrorsEnabled ? "Custom exception text for end users" : "Custom exception text for developers"));

                context.ExceptionHandled = true;
            }
        }

        static string GetJson(string message) {
            return $"{{ \"Message\":\"{message}\" }}";
        }
    }
}

Visual Basic
Imports Microsoft.VisualBasic
Imports DevExpress.DashboardWeb.Mvc
Imports System
Imports System.Net
Imports System.Web.Mvc

Namespace MvcCustomTextForInternalDashboardErrors
    Public Class CustomDashboardController
        Inherits DashboardController
        Protected Overrides Sub OnException(ByVal context As ExceptionContext)
            Dim exception = context.Exception
            If exception IsNot Nothing AndAlso context.HttpContext IsNot Nothing Then
                Dim response = context.HttpContext.Response
                response.StatusCode = CInt(Fix(HttpStatusCode.BadRequest))

                response.ContentType = "application/json"
                ' The 'mode' attribute in the 'customErrors' section of the Web.config file specifies whether an application is in development mode.
                Dim isCustomErrorsEnabled As Boolean = If(System.Web.HttpContext.Current IsNot Nothing, System.Web.HttpContext.Current.IsCustomErrorEnabled, True)

                response.Write(GetJson(If(isCustomErrorsEnabled, "Custom exception text for end users", "Custom exception text for developers")))

                context.ExceptionHandled = True
            End If
        End Sub

        Private Shared Function GetJson(ByVal message As String) As String
            Return $"{{ ""Message"":""{message}"" }}"
        End Function
    End Class
End Namespace

MvcCustomTextForInternalDashboardErrors/App_Start/DashboardConfig.cs(vb)

C#
VB.NET

C#
using DevExpress.DashboardWeb.Mvc;
using System.Web.Routing;

namespace MvcCustomTextForInternalDashboardErrors {
    public class DashboardConfig
    {
        public static void RegisterService(RouteCollection routes)
        {
            //routes.MapDashboardRoute();

            // Uncomment this line to save dashboards to the App_Data folder.
            //DashboardConfigurator.Default.SetDashboardStorage(new DashboardFileStorage(@"~/App_Data/"));

            // Uncomment these lines to create an in-memory storage of dashboard data sources. Use the DataSourceInMemoryStorage.RegisterDataSource
            // method to register the existing data source in the created storage.
            //var dataSourceStorage = new DataSourceInMemoryStorage();
            //DashboardConfigurator.Default.SetDataSourceStorage(dataSourceStorage);


            routes.MapDashboardRoute("dashboardDesigner", "CustomDashboard", new string[] { "MvcCustomTextForInternalDashboardErrors" });
        }
    }
}

Visual Basic
Imports Microsoft.VisualBasic
Imports DevExpress.DashboardWeb.Mvc
Imports System.Web.Routing

Namespace MvcCustomTextForInternalDashboardErrors
    Public Class DashboardConfig
        Public Shared Sub RegisterService(ByVal routes As RouteCollection)
            'routes.MapDashboardRoute();

            ' Uncomment this line to save dashboards to the App_Data folder.
            'DashboardConfigurator.Default.SetDashboardStorage(new DashboardFileStorage(@"~/App_Data/"));

            ' Uncomment these lines to create an in-memory storage of dashboard data sources. Use the DataSourceInMemoryStorage.RegisterDataSource
            ' method to register the existing data source in the created storage.
            'var dataSourceStorage = new DataSourceInMemoryStorage();
            'DashboardConfigurator.Default.SetDataSourceStorage(dataSourceStorage);


            routes.MapDashboardRoute("dashboardDesigner", "CustomDashboard", New String() { "MvcCustomTextForInternalDashboardErrors" })
        End Sub
    End Class
End Namespace

MvcCustomTextForInternalDashboardErrors/Views/Default/Index.cshtml

Razor
@using System.Web.UI.WebControls

<!DOCTYPE html>

<html>
<head>
    @Html.DevExpress().GetStyleSheets(
            new StyleSheet { ExtensionSuite = ExtensionSuite.NavigationAndLayout },
            new StyleSheet { ExtensionSuite = ExtensionSuite.Editors },
            new StyleSheet { ExtensionSuite = ExtensionSuite.Dashboard }
        )
    @Html.DevExpress().GetScripts(
        new Script { ExtensionSuite = ExtensionSuite.NavigationAndLayout },
        new Script { ExtensionSuite = ExtensionSuite.Editors },
        new Script { ExtensionSuite = ExtensionSuite.Dashboard }
    )
    <style type="text/css">
        html, body, form {  
            height: 100%;  
            margin: 0;  
            padding: 0;  
            overflow: hidden;  
        }
    </style>
</head>
<body>
    @Html.DevExpress().Dashboard(settings => {
        settings.Name = "Dashboard";
        settings.ControllerName = "CustomDashboard";
        settings.Width = Unit.Percentage(100);
        settings.Height = Unit.Percentage(100);
    }).GetHtml()
</body>
</html>

MvcCustomTextForInternalDashboardErrors/Views/Default/Index.vbhtml

Code
@Imports System.Web.UI.WebControls

<!DOCTYPE html>

<html>
<head>
    @Html.DevExpress().GetStyleSheets(
        New StyleSheet With {.ExtensionSuite = ExtensionSuite.NavigationAndLayout},
        New StyleSheet With {.ExtensionSuite = ExtensionSuite.Editors},
        New StyleSheet With {.ExtensionSuite = ExtensionSuite.Dashboard}
    )
    @Html.DevExpress().GetScripts(
        New Script With {.ExtensionSuite = ExtensionSuite.NavigationAndLayout},
        New Script With {.ExtensionSuite = ExtensionSuite.Editors},
        New Script With {.ExtensionSuite = ExtensionSuite.Dashboard}
    )
    <style type="text/css">
        html, body, form {  
            height: 100%;  
            margin: 0;  
            padding: 0;  
            overflow: hidden;  
        }
    </style>
</head>
<body>
    @Html.DevExpress().Dashboard(
    Sub(settings)
        settings.ControllerName = "CustomDashboard"
        settings.Name = "Dashboard"
        settings.Width = Unit.Percentage(100)
        settings.Height = Unit.Percentage(100)
    End Sub).GetHtml()
</body>
</html>

MvcThrowCustomExceptionDashboardErrorToast/Global.asax.cs(vb)

C#
VB.NET

C#
using System;
using System.Collections.Generic;
using System.Web.Mvc;
using System.Web.Routing;
using System.Xml.Linq;
using DevExpress.DashboardWeb;

namespace MvcThrowCustomExceptionDashboardErrorToast {
    public class MvcApplication : System.Web.HttpApplication {
        protected void Application_Start() {
            ControllerBuilder.Current.SetControllerFactory(typeof(RestrictedControllerFactory));
            DashboardConfig.RegisterService(RouteTable.Routes);
            AreaRegistration.RegisterAllAreas();
            RouteConfig.RegisterRoutes(RouteTable.Routes);
            DashboardConfigurator.Default.SetDashboardStorage(new CustomDashboardStorage());
        }
    }

    public class CustomException : Exception {
        public const string SafeMessage = "Custom exception text for end users";
        public const string UnsafeMessage = "Custom exception text for developers";
    }

    public class CustomDashboardStorage : IDashboardStorage {
        IEnumerable<DashboardInfo> IDashboardStorage.GetAvailableDashboardsInfo() {
            return new[] {
                new DashboardInfo { ID = "Dashboard", Name = "Dashboard" }
            };
        }
        XDocument IDashboardStorage.LoadDashboard(string dashboardID) {
            throw new CustomException();
        }
        void IDashboardStorage.SaveDashboard(string dashboardID, XDocument dashboard) {
        }
    }
}

Visual Basic
Imports System
Imports System.Collections.Generic
Imports System.Web.Mvc
Imports System.Web.Routing
Imports System.Xml.Linq
Imports DevExpress.DashboardWeb

Namespace MvcThrowCustomExceptionDashboardErrorToast
    Public Class MvcApplication
        Inherits System.Web.HttpApplication
        Protected Sub Application_Start()
            DashboardConfig.RegisterService(RouteTable.Routes)
            AreaRegistration.RegisterAllAreas()
            RouteConfig.RegisterRoutes(RouteTable.Routes)
            ControllerBuilder.Current.SetControllerFactory(GetType(RestrictedControllerFactory))

            DashboardConfigurator.Default.SetDashboardStorage(New CustomDashboardStorage())
        End Sub
    End Class

    Public Class CustomException
        Inherits Exception
        Public Const SafeMessage As String = "Custom exception text for end users"
        Public Const UnsafeMessage As String = "Custom exception text for developers"
    End Class

    Public Class CustomDashboardStorage
        Implements IDashboardStorage
        Private Function GetAvailableDashboardsInfo() As IEnumerable(Of DashboardInfo) Implements IDashboardStorage.GetAvailableDashboardsInfo
            Return {New DashboardInfo With {
                .ID = "Dashboard",
                .Name = "Dashboard"
            }}
        End Function

        Private Function LoadDashboard(ByVal dashboardID As String) As XDocument Implements IDashboardStorage.LoadDashboard
            ' Custom Exception:
            Throw New CustomException()
        End Function

        Private Sub SaveDashboard(ByVal dashboardID As String, ByVal dashboard As XDocument) Implements IDashboardStorage.SaveDashboard
        End Sub
    End Class
End Namespace

MvcThrowCustomExceptionDashboardErrorToast/App_Start/DashboardConfig.cs(vb)

C#
VB.NET

C#
using System.Web.Routing;
using DevExpress.DashboardWeb;
using DevExpress.DashboardWeb.Mvc;

namespace MvcThrowCustomExceptionDashboardErrorToast
{
    public class DashboardConfig
    {
        public static void RegisterService(RouteCollection routes)
        {
            //routes.MapDashboardRoute();

            // Uncomment this line to save dashboards to the App_Data folder.
            //DashboardConfigurator.Default.SetDashboardStorage(new DashboardFileStorage(@"~/App_Data/"));

            // Uncomment these lines to create an in-memory storage of dashboard data sources. Use the DataSourceInMemoryStorage.RegisterDataSource
            // method to register the existing data source in the created storage.
            //var dataSourceStorage = new DataSourceInMemoryStorage();
            //DashboardConfigurator.Default.SetDataSourceStorage(dataSourceStorage);


            routes.MapDashboardRoute("dashboardDesigner", "CustomDashboard", new string[] { "MvcThrowCustomExceptionDashboardErrorToast" });
        }
    }
}

Visual Basic
Imports Microsoft.VisualBasic
Imports System.Web.Routing
Imports DevExpress.DashboardWeb
Imports DevExpress.DashboardWeb.Mvc

Namespace MvcThrowCustomExceptionDashboardErrorToast
    Public Class DashboardConfig
        Public Shared Sub RegisterService(ByVal routes As RouteCollection)
            'routes.MapDashboardRoute();

            ' Uncomment this line to save dashboards to the App_Data folder.
            'DashboardConfigurator.Default.SetDashboardStorage(new DashboardFileStorage(@"~/App_Data/"));

            ' Uncomment these lines to create an in-memory storage of dashboard data sources. Use the DataSourceInMemoryStorage.RegisterDataSource
            ' method to register the existing data source in the created storage.
            'var dataSourceStorage = new DataSourceInMemoryStorage();
            'DashboardConfigurator.Default.SetDataSourceStorage(dataSourceStorage);


            routes.MapDashboardRoute("dashboardDesigner", "CustomDashboard", New String() { "MvcThrowCustomExceptionDashboardErrorToast" })
        End Sub
    End Class
End Namespace

MvcThrowCustomExceptionDashboardErrorToast/Controllers/CustomDashboardController.cs(vb)

C#
VB.NET

C#
using System.Net;
using System.Web.Mvc;
using DevExpress.DashboardWeb.Mvc;

namespace MvcThrowCustomExceptionDashboardErrorToast.Controllers {
    public class CustomDashboardController : DashboardController {
        protected override void OnException(ExceptionContext context) {
            var exception = context.Exception;
            if(exception != null && context.HttpContext != null) {
                var response = context.HttpContext.Response;
                response.StatusCode = (int)HttpStatusCode.BadRequest;
                response.ContentType = "application/json";

                CustomException customException = exception as CustomException;
                bool isCustomErrorsEnabled = System.Web.HttpContext.Current != null ? System.Web.HttpContext.Current.IsCustomErrorEnabled : true;
                string message = customException != null ? (isCustomErrorsEnabled ? CustomException.SafeMessage : CustomException.UnsafeMessage) : "";
                response.Write(GetJson(message));

                context.ExceptionHandled = true;
            }
        }

        static string GetJson(string message) {
            return $"{{ \"Message\":\"{message}\" }}";
        }
    }
}

Visual Basic
Imports Microsoft.VisualBasic
Imports System.Net
Imports System.Web.Mvc
Imports DevExpress.DashboardWeb.Mvc

Namespace MvcThrowCustomExceptionDashboardErrorToast.Controllers
    Public Class CustomDashboardController
        Inherits DashboardController
        Protected Overrides Sub OnException(ByVal context As ExceptionContext)
            Dim exception = context.Exception
            If exception IsNot Nothing AndAlso context.HttpContext IsNot Nothing Then
                Dim response = context.HttpContext.Response
                response.StatusCode = CInt(Fix(HttpStatusCode.BadRequest))
                response.ContentType = "application/json"

                Dim customException As CustomException = TryCast(exception, CustomException)
                Dim isCustomErrorsEnabled As Boolean = If(System.Web.HttpContext.Current IsNot Nothing, System.Web.HttpContext.Current.IsCustomErrorEnabled, True)
                Dim message As String = If(customException IsNot Nothing, (If(isCustomErrorsEnabled, CustomException.SafeMessage, CustomException.UnsafeMessage)), "")
                response.Write(GetJson(message))

                context.ExceptionHandled = True
            End If
        End Sub

        Private Shared Function GetJson(ByVal message As String) As String
            Return $"{{ ""Message"":""{message}"" }}"
        End Function
    End Class
End Namespace

MvcThrowCustomExceptionDashboardErrorToast/Views/Default/Index.cshtml

Razor
@using System.Web.UI.WebControls

<!DOCTYPE html>

<html>
<head>
    @Html.DevExpress().GetStyleSheets(
            new StyleSheet { ExtensionSuite = ExtensionSuite.NavigationAndLayout },
            new StyleSheet { ExtensionSuite = ExtensionSuite.Editors },
            new StyleSheet { ExtensionSuite = ExtensionSuite.Dashboard }
        )
    @Html.DevExpress().GetScripts(
        new Script { ExtensionSuite = ExtensionSuite.NavigationAndLayout },
        new Script { ExtensionSuite = ExtensionSuite.Editors },
        new Script { ExtensionSuite = ExtensionSuite.Dashboard }
    )

    <style type="text/css">
        html, body, form {  
            height: 100%;  
            margin: 0;  
            padding: 0;  
            overflow: hidden;  
        }
    </style>
</head>
<body>
    @Html.DevExpress().Dashboard(settings => {
        settings.ControllerName = "CustomDashboard";
        settings.Name = "Dashboard";
        settings.Width = Unit.Percentage(100);
        settings.Height = Unit.Percentage(100);
    }).GetHtml()
</body>
</html>

MvcThrowCustomExceptionDashboardErrorToast/Views/Default/Index.vbhtml

Code
@Imports System.Web.UI.WebControls

<!DOCTYPE html>

<html>
<head>
    @Html.DevExpress().GetStyleSheets(
        New StyleSheet With {.ExtensionSuite = ExtensionSuite.NavigationAndLayout},
        New StyleSheet With {.ExtensionSuite = ExtensionSuite.Editors},
        New StyleSheet With {.ExtensionSuite = ExtensionSuite.Dashboard}
    )
    @Html.DevExpress().GetScripts(
        New Script With {.ExtensionSuite = ExtensionSuite.NavigationAndLayout},
        New Script With {.ExtensionSuite = ExtensionSuite.Editors},
        New Script With {.ExtensionSuite = ExtensionSuite.Dashboard}
    )

    <style type="text/css">
        html, body, form {  
            height: 100%;  
            margin: 0;  
            padding: 0;  
            overflow: hidden;  
        }
    </style>
</head>
<body>
    @Html.DevExpress().Dashboard(
    Sub(settings)
        settings.ControllerName = "CustomDashboard"
        settings.Name = "Dashboard"
        settings.Width = Unit.Percentage(100)
        settings.Height = Unit.Percentage(100)
    End Sub).GetHtml()
</body>
</html>

Natalia Kazakova (DevExpress)

last modified 5 years ago

Modified: June 3, 2020 9:03 PM

Platform: Business Intelligence

Product: Dashboard for MVC

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Dashboard for MVC - How to handle errors

How to specify custom text for internal Dashboard errors

Files to Review

Description

How to throw a custom exception during a server-side processing and display the error in the Dashboard error toast

Files to Review

Description

Documentation

More Examples

Example Code

Recently viewed tickets