dotnet/aspnetcore · error · InvalidOperationException

The property '{parameterName}' on component type '{targetTyp

Error message

The property '{parameterName}' on component type '{targetType.FullName}' cannot be set using a cascading value.

What it means

Thrown by ComponentProperties.ThrowForSettingParameterWithCascadingValue when a non-cascading ([Parameter]-only) property receives a value through the framework's cascading-value pipeline. This is usually an internal/infrastructure condition rather than a user markup error, because users do not directly route cascading values to specific parameters.

Source

Thrown at src/Components/Components/src/Reflection/ComponentProperties.cs:232

        {
            throw new InvalidOperationException(
                $"Object of type '{targetType.FullName}' does not have a property " +
                $"matching the name '{parameterName}'.");
        }
    }

    [DoesNotReturn]
    private static void ThrowForSettingCascadingParameterWithNonCascadingValue(Type targetType, string parameterName)
    {
        throw new InvalidOperationException(
            $"The property '{parameterName}' on component type '{targetType.FullName}' cannot be set " +
            $"explicitly because it only accepts cascading values.");
    }

    [DoesNotReturn]
    private static void ThrowForSettingParameterWithCascadingValue(Type targetType, string parameterName)
    {
        throw new InvalidOperationException(
            $"The property '{parameterName}' on component type '{targetType.FullName}' cannot be set " +
            $"using a cascading value.");
    }

    [DoesNotReturn]
    private static void ThrowForCaptureUnmatchedValuesConflict(Type targetType, string parameterName, Dictionary<string, object> unmatched)
    {
        throw new InvalidOperationException(
            $"The property '{parameterName}' on component type '{targetType.FullName}' cannot be set explicitly " +
            $"when also used to capture unmatched values. Unmatched values:" + Environment.NewLine +
            string.Join(Environment.NewLine, unmatched.Keys));
    }

    [DoesNotReturn]
    private static void ThrowForMultipleCaptureUnmatchedValuesParameters([DynamicallyAccessedMembers(Component)] Type targetType)
    {
        var propertyNames = new List<string>();
        foreach (var property in targetType.GetProperties(BindablePropertyFlags))

View on GitHub (pinned to 294cab2f9b)

Solutions

Verify parameters meant to receive query/route values are attributed correctly (use [SupplyParameterFromQuery] alongside [Parameter]).
Review custom cascading-value providers to ensure they target cascading parameters, not plain parameters.
This usually signals an infrastructure misconfiguration - audit how the cascading value is being supplied.
Check for a framework version regression if the configuration was previously valid.

Example fix

// before: query value routed as cascading to a plain [Parameter]
[Parameter] public int Page { get; set; } // misconfigured query binding

// after
[Parameter] [SupplyParameterFromQuery(Name = "page")]
public int Page { get; set; }

Defensive patterns

Strategy: validation

Validate before calling

// Ensure query/route-bound parameters carry the right attributes so the framework
// does not route a cascading value into a plain [Parameter].
static bool IsValidQueryParameter(PropertyInfo p)
    => p.GetCustomAttribute<ParameterAttribute>() is not null
       && p.GetCustomAttribute<SupplyParameterFromQueryAttribute>() is not null;

Prevention

Use [Parameter] together with [SupplyParameterFromQuery] for query-bound parameters, not cascading-value suppliers.
Audit custom cascading-value suppliers to ensure they target [CascadingParameter] properties only.
Treat this error as an infrastructure/config signal - review how the cascading value is supplied.
Watch for framework regressions if a previously-valid setup starts throwing.

When it happens

Trigger: Framework infrastructure (e.g. SupplyParameterFromQuery, custom cascading value suppliers) attempting to deliver a cascading value to a [Parameter]-only property; a misconfigured cascading value supplier targeting the wrong parameter.

Common situations: A custom component that supplies cascading values targeting a non-cascading parameter; mixing [SupplyParameterFromQuery] incorrectly; a framework integration bug routing a query/route value as a cascading value to a plain parameter.

Related errors

AI-assisted analysis of dotnet/aspnetcore@294cab2f9b (2026-08-06). Data as JSON: /api/errors/7b85d9b0b79307e0. Report an issue: GitHub.