CA1853: Unnecessary call to 'Dictionary.ContainsKey(key)'

#Cause

A call to System.Collections.Generic.Dictionary.Remove() is guarded with a call to System.Collections.Generic.Dictionary.ContainsKey().

#Rule description

There's no need to guard Dictionary.Remove(key) with Dictionary.ContainsKey(key). System.Collections.Generic.Dictionary.Remove() already checks whether the key exists and doesn't throw if it doesn't exist.

#How to fix violations

Remove the guarding code that calls System.Collections.Generic.Dictionary.ContainsKey().

#Example

The following code snippet shows a violation of CA1853:

Dictionary<string, int> d = new();
if (d.ContainsKey("name"))
    d.Remove("name");

Class C
    Shared Sub S()
        Dim d As New Dictionary(Of String, Integer)
        If d.ContainsKey("name") Then
            d.Remove("name")
        End If
    End Sub
End Class

The following code snippet fixes the violation:

Dictionary<string, int> d = new();
d.Remove("name");

Class C
    Shared Sub S()
        Dim d As New Dictionary(Of String, Integer)
        d.Remove("name")
    End Sub
End Class

#When to suppress warnings

It's safe to suppress a warning if performance isn't a concern.

#Suppress a warning

If you just want to suppress a single violation, add preprocessor directives to your source file to disable and then re-enable the rule.

#pragma warning disable CA1853
// The code that's violating the rule is on this line.
#pragma warning restore CA1853

To disable the rule for a file, folder, or project, set its severity to none in the configuration file.

[*.{cs,vb}]
dotnet_diagnostic.CA1853.severity = none

For more information, see How to suppress code analysis warnings.