# MustBeFalse

> An extension method for Assert.IsFalse.

## Definition

* **Type:** Method
* **Namespace:** [UnityEngine.Assertions.Must](/engine/6000.7/script-reference/unityengine/assertions/must.md)
* **Assembly:** UnityEngine.CoreModule

## MustBeFalse(bool)

An extension method for [Assert.IsFalse](/engine/6000.7/script-reference/unityengine/assertions/assert/isfalse.md).

> **Warning:**
>
> **Deprecated.** Must extensions are deprecated. Use UnityEngine.Assertions.Assert instead

```csharp
[Conditional("UNITY_ASSERTIONS")]
public static void MustBeFalse(this bool value)
```

### Parameters

**** (\[bool]\(https\://learn.microsoft.com/dotnet/api/system.boolean)): 

### Examples

```csharp
using UnityEngine;
using UnityEngine.Assertions;
using UnityEngine.Assertions.Must;

public class AssertionExampleClass : MonoBehaviour
{
    GameObject go;
    void Update()
    {
        //Make sure the Game Object is never in active state
        go.activeSelf.MustBeFalse();
    }
}
```

## MustBeFalse(bool, string)

An extension method for [Assert.IsFalse](/engine/6000.7/script-reference/unityengine/assertions/assert/isfalse.md).

> **Warning:**
>
> **Deprecated.** Must extensions are deprecated. Use UnityEngine.Assertions.Assert instead

```csharp
[Conditional("UNITY_ASSERTIONS")]
public static void MustBeFalse(this bool value, string message)
```

### Parameters

**** (\[bool]\(https\://learn.microsoft.com/dotnet/api/system.boolean)): **** (\[string]\(https\://learn.microsoft.com/dotnet/api/system.string)): 

### Examples

```csharp
using UnityEngine;
using UnityEngine.Assertions;
using UnityEngine.Assertions.Must;

public class AssertionExampleClass : MonoBehaviour
{
    GameObject go;
    void Update()
    {
        //Make sure the Game Object is never in active state
        go.activeSelf.MustBeFalse();
    }
}
```