---
title: Exceptions must be thrown
description: Datadog, the leading service for cloud-scale monitoring.
breadcrumbs: >-
  Docs > Datadog Security > Code Security > Static Code Analysis (SAST) > SAST
  Rules > Exceptions must be thrown
---

# Exceptions must be thrown

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## Metadata{% #metadata %}

**ID:** `csharp-best-practices/exception-must-be-thrown`

**Language:** C#

**Severity:** Warning

**Category:** Best Practices

## Description{% #description %}

Exceptions should be thrown and not just created. An expression such as `new Exception(...)` does not throw the exception. You should use the keyword `throw` to throw the exception`.

#### Learn More{% #learn-more %}

- [Exceptions in C#](https://learn.microsoft.com/en-us/dotnet/api/system.exception?view=net-8.0)

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

```csharp
using System.Xml;

class MyClass {
    public void myMethod()
    {
        var a = new MyException("something bad happened");
    }
}
```

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

```csharp
using System.Xml;

class MyClass {
    public void myMethod()
    {
        var bla = new MyClass("something bad happened");
    }
    public void foo() {
            Formatter formatter = language switch
            {
                SqlLanguage.Sql => new StandardSqlFormatter(),
                SqlLanguage.Tsql => new TSqlFormatter(),
                SqlLanguage.Spark => new SparkSqlFormatter(),
                SqlLanguage.RedShift => new RedshiftFormatter(),
                SqlLanguage.PostgreSql => new PostgreSqlFormatter(),
                SqlLanguage.PlSql => new PlSqlFormatter(),
                SqlLanguage.N1ql => new N1qlFormatter(),
                SqlLanguage.MySql => new MySqlFormatter(),
                SqlLanguage.MariaDb => new MariaDbFormatter(),
                SqlLanguage.Db2 => new Db2Formatter(),
                _ => throw new NotSupportedException(),
            };
    }
}
```

```csharp
using System.Xml;

class MyClass {
    public void myMethod()
    {
        throw new MyException("something bad happened");
    }
}
```
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