dotnet/aspnetcore · error · InvalidOperationException

SectionContent requires a non-null value either for 'Section

Error message

SectionContent requires a non-null value either for 'SectionName' or 'SectionId'.

What it means

SectionContent must target an outlet; if neither SectionName nor SectionId is supplied, SetParametersAsync throws InvalidOperationException because there is no identifier to register with the SectionRegistry. The component has no default-free mode — it always needs a target. Without an identifier the registry cannot AddProvider, so this guards against a silently unregistered provider.

Source

Thrown at src/Components/Components/src/Sections/SectionContent.cs:68

        SetParameterValues(parameters);

        object? identifier;

        if (SectionName is not null && SectionId is not null)
        {
            throw new InvalidOperationException($"{nameof(SectionContent)} requires that '{nameof(SectionName)}' and '{nameof(SectionId)}' cannot both have non-null values.");
        }
        else if (SectionName is not null)
        {
            identifier = SectionName;
        }
        else if (SectionId is not null)
        {
            identifier = SectionId;
        }
        else
        {
            throw new InvalidOperationException($"{nameof(SectionContent)} requires a non-null value either for '{nameof(SectionName)}' or '{nameof(SectionId)}'.");
        }

        if (!object.Equals(identifier, _registeredIdentifier) || IsDefaultContent != _registeredIsDefaultContent)
        {
            if (_registeredIdentifier is not null)
            {
                _registry.RemoveProvider(_registeredIdentifier, this);
            }

            _registry.AddProvider(identifier, this, IsDefaultContent);
            _registeredIdentifier = identifier;
            _registeredIsDefaultContent = IsDefaultContent;
        }

        _registry.NotifyContentProviderChanged(identifier, this);

        return Task.CompletedTask;
    }

View on GitHub (pinned to 294cab2f9b)

Solutions

1. Add SectionName="some-name" or SectionId="@someNonNullOrootObject" to every <SectionContent> usage.
2. If the identifier is data-driven, ensure it is non-null before the component renders, or wrap the SectionContent in an @if block that gates on the identifier.
3. Grep the markup for '<SectionContent' occurrences missing both SectionName and SectionId.

Example fix

// before
<SectionContent>
    <Header />
</SectionContent>

// after
<SectionContent SectionName="header">
    <Header />
</SectionContent>

// Render SectionContent only when an identifier exists
@if (!string.IsNullOrEmpty(sectionName) || sectionId is not null)
{
    <SectionContent SectionName="@sectionName" SectionId="@sectionId">
        @ChildContent
    </SectionContent>
}

static bool HasSectionIdentifier(string? name, object? id) =>
    !string.IsNullOrEmpty(name) || id is not null;

When it happens

Trigger: Declaring <SectionContent> with only ChildContent and no SectionName/SectionId, or dynamically rendering a SectionContent whose identifier parameters are both conditionally null. Hit whenever SetParametersAsync runs and both identifier parameters are null.

Common situations: Forgot to add the identifier attribute; bound the identifier to a nullable expression that evaluates to null at first render; refactored markup and dropped the SectionName attribute.

Related errors

• SectionContent requires that 'SectionName' and 'SectionId' c
• Unknown parameter '{param.Name}'
• SectionOutlet requires that 'SectionName' and 'SectionId' ca
• SectionOutlet requires a non-null value either for 'SectionN
• Unable to set property '{parameterName}' on object of type '

AI-assisted analysis of dotnet/aspnetcore@294cab2f9b (2026-08-06). Data as JSON: /api/errors/1e362ca2af8c1568. Report an issue: GitHub.