AspNetCore.Docs/aspnetcore/diagnostics/bl0002.md

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---
title: "BL0002: Component has multiple CaptureUnmatchedValues parameters"
description: "Learn about analysis rule BL0002: Component has multiple CaptureUnmatchedValues parameters"
author: pranavkm
monikerRange: '>= aspnetcore-3.1'
ms.author: riande
ms.date: 10/21/2021
uid: diagnostics/bl0002
---
# BL0002: Component has multiple CaptureUnmatchedValues parameters
| | Value |
|-|-|
| **Rule ID** |BL0002|
| **Category** |Usage|
| **Fix is breaking or non-breaking** |Non-breaking|
## Cause
More than one parameter on a type deriving from <xref:Microsoft.AspNetCore.Components.ComponentBase> is annotated with `CaptureUnmatchedValues = true`.
## Rule description
For a component, exactly one parameter is expected to have the <xref:Microsoft.AspNetCore.Components.ParameterAttribute.CaptureUnmatchedValues> set to `true`.
```razor
@code
{
[Parameter(CaptureUnmatchedValues = true)] public Dictionary<string, object> Parameter1 { get; set; }
[Parameter(CaptureUnmatchedValues = true)] public Dictionary<string, object> Parameter2 { get; set; }
}
```
## How to fix violations
Limit a single parameter to have `CaptureUnmatchedValues` set.
```razor
@code
{
[Parameter(CaptureUnmatchedValues = true)] public Dictionary<string, object> Parameter1 { get; set; }
[Parameter] public Dictionary<string, object> Parameter2 { get; set; }
}
```
## When to suppress warnings
Do not suppress a warning from this rule.