---
title: "MVC1004: Rename model bound parameter"
description: "Learn about analysis rule MVC1004: Rename model bound parameter"
author: pranavkm
monikerRange: '>= aspnetcore-3.1'
ms.author: riande
ms.date: 10/22/2021
uid: diagnostics/mvc1004
---
# MVC1004: Rename model bound parameter

| | Value |
|-|-|
| **Rule ID** |MVC1004|
| **Fix is breaking or non-breaking** |Breaking|

## Cause

A model bound parameter has the same name as one of its properties.

### Rule description

Model binding a complex parameter with a property that has the same name may result in unexpected binding behavior. Consider renaming the parameter, or using a binding attribute to specify a different name.

Consider the following code:

```csharp
public class HomeController : Controller
{
    public IActionResult Get(SearchModel search)
    {
        ...
    }
}

public class SearcModel
{
    public string Search { get; set; }
}
```

In this model, the parameter and its property are both named `Search`, which results in model binding attempting to bind the property as `search.Search`. Naming a parameter and its property the same prevents binding to a value without a prefix such as a query that looks like `?search=MySearchTerm`.

## How to fix violations

* Rename the parameter if its prefix is not used during binding:
```csharp
public IActionResult Get(SearchModel model)
{
    ...
}
```

Renaming a parameter on a public type could be considered a breaking change since it changes a library's public API surface.

* If this is problematic, consider using a model binding attribute such as `Bind` to specify the model binding prefix:

```csharp
public IActionResult Get([Bind(Prefix = "")] SearchModel search)
{
    ...
}
```

## When to suppress warnings

Warnings can be suppressed if you intend to use the parameter name as a prefix during model binding.