---
title: ToString() should never return `null`
description: Datadog, the leading service for cloud-scale monitoring.
breadcrumbs: >-
  Docs > Datadog Security > Code Security > Static Code Analysis (SAST) > SAST
  Rules > ToString() should never return `null`
---

> For the complete documentation index, see [llms.txt](https://docs.datadoghq.com/llms.txt).

# ToString() should never return `null`

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## Metadata{% #metadata %}

**ID:** `csharp-best-practices/tostring-not-return-null`

**Language:** C#

**Severity:** Warning

**Category:** Error Prone

## Description{% #description %}

The method `ToString()` should always return a value (for example, a string) and never return `null`. Instead of returning `null`, return `string.Empty`, which is an empty string.

## Non-Compliant Code Examples{% #non-compliant-code-examples %}

```csharp
class MyClass {
    public override string ToString()
    {
        if(foo) {
            return null;
        }
        return null;
        
    }
}
```

```csharp
class MyClass {
    public override string ToString()
    {
        return null;
    }
}
```

## Compliant Code Examples{% #compliant-code-examples %}

```csharp
class MyClass {
    public override string ToString()
    {
        return string.Empty;;    
    }
}
```
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