dotnet/aspnetcore · error · InvalidOperationException

{nameof(DynamicComponent)} does not accept a parameter with

Error message

{nameof(DynamicComponent)} does not accept a parameter with the name '{entry.Name}'. To pass parameters to the dynamically-rendered component, use the '{nameof(Parameters)}' parameter.

What it means

Thrown by DynamicComponent.SetParametersAsync when it receives a parameter whose name is not 'Type' or 'Parameters'. DynamicComponent deliberately does not use CaptureUnmatchedValues, so arbitrary parameters are rejected — to pass values to the dynamically-rendered child component you must use the Parameters dictionary. The rejection is at DynamicComponent.cs:77-81.

Source

Thrown at src/Components/Components/src/DynamicComponent.cs:79

    /// <inheritdoc />
    [UnconditionalSuppressMessage("Trimming", "IL2072", Justification = "We expect that types used with DynamicComponent will be defined in assemblies that don't get trimmed.")]
    public Task SetParametersAsync(ParameterView parameters)
    {
        // This manual parameter assignment logic will be marginally faster than calling
        // ComponentProperties.SetProperties.
        foreach (var entry in parameters)
        {
            if (entry.Name.Equals(nameof(Type), StringComparison.OrdinalIgnoreCase))
            {
                Type = (Type)entry.Value;
            }
            else if (entry.Name.Equals(nameof(Parameters), StringComparison.OrdinalIgnoreCase))
            {
                Parameters = (IDictionary<string, object>)entry.Value;
            }
            else
            {
                throw new InvalidOperationException(
                    $"{nameof(DynamicComponent)} does not accept a parameter with the name '{entry.Name}'. To pass parameters to the dynamically-rendered component, use the '{nameof(Parameters)}' parameter.");
            }
        }

        if (Type is null)
        {
            throw new InvalidOperationException($"{nameof(DynamicComponent)} requires a non-null value for the parameter {nameof(Type)}.");
        }

        _renderHandle.Render(_cachedRenderFragment);
        return Task.CompletedTask;
    }

    void Render(RenderTreeBuilder builder)
    {
        builder.OpenComponent(0, Type);

        if (Parameters != null)

View on GitHub (pinned to 294cab2f9b)

Solutions

Pass child parameters via the Parameters dictionary: <DynamicComponent Type="@t" Parameters="@params" /> where params is a Dictionary<string,object>.
Remove any direct attributes that aren't Type or Parameters.

Example fix

// before
<DynamicComponent Type="@componentType" Title="@title" OnClick="@handler" />

// after
<DynamicComponent Type="@componentType" Parameters="@_params" />
@code {
    private Dictionary<string, object> _params = new()
    {
        ["Title"] = title,
        ["OnClick"] = EventCallback.Create(this, handler)
    };
}

Defensive patterns

Strategy: validation

Validate before calling

var valid = new[] { "Type", "Parameters" };
foreach (var p in parameters)
    if (!valid.Contains(p.Name))
        throw new InvalidOperationException($"Use Parameters dictionary, not '{p.Name}'.");

Prevention

Always pass child component values via the Parameters dictionary on DynamicComponent.
Never add direct attributes other than Type or Parameters.

When it happens

Trigger: Writing <DynamicComponent SomeProp="x"> instead of passing SomeProp via the Parameters dictionary; trying to set component parameters directly on DynamicComponent in markup.

Common situations: Assuming DynamicComponent forwards unmatched attributes to the child; copy-pasting a usage that worked with a concrete component but applying it to DynamicComponent.

Related errors

AI-assisted analysis of dotnet/aspnetcore@294cab2f9b (2026-08-06). Data as JSON: /api/errors/12a3be476a93ae64. Report an issue: GitHub.