Catch all exceptions with ErrorBoundary

Environment

Product

UI for Blazor

Description

Is it possible to catch all errors in Blazor Server like in MVC 5 in global.asax on Application_Error?

We are trying to integrate the ErrorBoundary component. It seems it does not catch exceptions thrown from the Window component. What is the correct way of using ErrorBoundary with the Telerik Blazor components?

Solution

As of .NET 6, you can use the ErrorBoundary component to catch exceptions.

To do so, wrap the existing content in an ErrorBoundary component. It will render error UI when unhandled exceptions are thrown. The application continues to function normally, but the error boundary handles the exception in the affected component.

ErrorBoundary can wrap any Blazor component or the @Body in MainLayout.razor, so it catches all exceptions globally.

Consider the following application layout setup:

• <TelerikRootComponent> is inside TelerikLayout.razor
• MainLayout.razor references TelerikLayout.razor

TelerikLayout.razor

RAZOR

@inherits LayoutComponentBase

<TelerikRootComponent>
    @Body
</TelerikRootComponent>

MainLayout.razor

RAZOR

@layout TelerikLayout
@inherits LayoutComponentBase

<div class="page">
    <div class="sidebar">
        <NavMenu />
    </div>

    <div class="main">
        <div class="content px-4">
            <ErrorBoundary>
                @Body
            </ErrorBoundary>
        </div>
    </div>
</div>

The ErrorBoundary component can catch exceptions in the Telerik Blazor components as well. The usual approach to catch all exceptions is to wrap ErrorBoundary around the @Body element. However, this may not catch errors thrown in components such as Window, Dialog, and other popups. These components are not rendered in their place of declaration and essentially they are outside the @Body from MainLayout.razor.

To handle this, wrap the ErrorBoundary component around the <TelerikRootComponent>. This is the topmost element our components can access.

TelerikLayout.razor

RAZOR

@inherits LayoutComponentBase

<ErrorBoundary>
    <TelerikRootComponent>
        @Body
    </TelerikRootComponent>
</ErrorBoundary>

If the application is using only one layout file, it should look like this:

MainLayout.razor

RAZOR

@inherits LayoutComponentBase

<ErrorBoundary>
    <TelerikRootComponent>
        <div class="page">
            <div class="sidebar">
                <NavMenu />
            </div>

            <div class="main">
                <div class="content px-4">
                    @Body
                </div>
            </div>
        </div>
    </TelerikRootComponent>
</ErrorBoundary>