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CA1304: Specify CultureInfo

  • บทความ
Property Value
Rule ID CA1304
Title Specify CultureInfo
Category Globalization
Fix is breaking or non-breaking Non-breaking
Enabled by default in .NET 9 No

Cause

A method or constructor calls a member that has an overload that accepts a System.Globalization.CultureInfo parameter, and the method or constructor does not call the overload that takes the CultureInfo parameter. This rule ignores calls to the following methods:

You can also configure more symbols to be excluded by this rule.

Rule description

When a CultureInfo or System.IFormatProvider object is not supplied, the default value that is supplied by the overloaded member might not have the effect that you want in all locales. Also, .NET members choose default culture and formatting based on assumptions that might not be correct for your code. To ensure the code works as expected for your scenarios, you should supply culture-specific information according to the following guidelines:

  • If the value will be displayed to the user, use the current culture. See CultureInfo.CurrentCulture.

  • If the value will be stored and accessed by software, that is, persisted to a file or database, use the invariant culture. See CultureInfo.InvariantCulture.

  • If you do not know the destination of the value, have the data consumer or provider specify the culture.

Even if the default behavior of the overloaded member is appropriate for your needs, it is better to explicitly call the culture-specific overload so that your code is self-documenting and more easily maintained.

Note

CultureInfo.CurrentUICulture is used only to retrieve localized resources by using an instance of the System.Resources.ResourceManager class.

How to fix violations

To fix a violation of this rule, use the overload that takes a CultureInfo argument.

When to suppress warnings

It is safe to suppress a warning from this rule when it is certain that the default culture is the correct choice, and where code maintainability is not an important development priority.

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 CA1304
// The code that's violating the rule is on this line.
#pragma warning restore CA1304

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

[*.{cs,vb}]
dotnet_diagnostic.CA1304.severity = none

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

Configure code to analyze

Use the following options to configure which parts of your codebase to run this rule on.

You can configure these options for just this rule, for all rules it applies to, or for all rules in this category (Globalization) that it applies to. For more information, see Code quality rule configuration options.

Exclude specific symbols

You can exclude specific symbols, such as types and methods, from analysis. For example, to specify that the rule should not run on any code within types named MyType, add the following key-value pair to an .editorconfig file in your project:

dotnet_code_quality.CAXXXX.excluded_symbol_names = MyType

Allowed symbol name formats in the option value (separated by |):

  • Symbol name only (includes all symbols with the name, regardless of the containing type or namespace).
  • Fully qualified names in the symbol's documentation ID format. Each symbol name requires a symbol-kind prefix, such as M: for methods, T: for types, and N: for namespaces.
  • .ctor for constructors and .cctor for static constructors.

Examples:

Option Value Summary
dotnet_code_quality.CAXXXX.excluded_symbol_names = MyType Matches all symbols named MyType.
dotnet_code_quality.CAXXXX.excluded_symbol_names = MyType1|MyType2 Matches all symbols named either MyType1 or MyType2.
dotnet_code_quality.CAXXXX.excluded_symbol_names = M:NS.MyType.MyMethod(ParamType) Matches specific method MyMethod with the specified fully qualified signature.
dotnet_code_quality.CAXXXX.excluded_symbol_names = M:NS1.MyType1.MyMethod1(ParamType)|M:NS2.MyType2.MyMethod2(ParamType) Matches specific methods MyMethod1 and MyMethod2 with the respective fully qualified signatures.

Exclude specific types and their derived types

You can exclude specific types and their derived types from analysis. For example, to specify that the rule should not run on any methods within types named MyType and their derived types, add the following key-value pair to an .editorconfig file in your project:

dotnet_code_quality.CAXXXX.excluded_type_names_with_derived_types = MyType

Allowed symbol name formats in the option value (separated by |):

  • Type name only (includes all types with the name, regardless of the containing type or namespace).
  • Fully qualified names in the symbol's documentation ID format, with an optional T: prefix.

Examples:

Option Value Summary
dotnet_code_quality.CAXXXX.excluded_type_names_with_derived_types = MyType Matches all types named MyType and all of their derived types.
dotnet_code_quality.CAXXXX.excluded_type_names_with_derived_types = MyType1|MyType2 Matches all types named either MyType1 or MyType2 and all of their derived types.
dotnet_code_quality.CAXXXX.excluded_type_names_with_derived_types = M:NS.MyType Matches specific type MyType with given fully qualified name and all of its derived types.
dotnet_code_quality.CAXXXX.excluded_type_names_with_derived_types = M:NS1.MyType1|M:NS2.MyType2 Matches specific types MyType1 and MyType2 with the respective fully qualified names, and all of their derived types.

Example showing how to fix violations

In the following example, BadMethod causes two violations of this rule. GoodMethod corrects the first violation by passing the invariant culture to String.Compare, and corrects the second violation by passing the current culture to String.ToLower because string3 is displayed to the user.

public class CultureInfoTest
{
    public void BadMethod(String string1, String string2, String string3)
    {
        if (string.Compare(string1, string2, false) == 0)
        {
            Console.WriteLine(string3.ToLower());
        }
    }

    public void GoodMethod(String string1, String string2, String string3)
    {
        if (string.Compare(string1, string2, false,
                          CultureInfo.InvariantCulture) == 0)
        {
            Console.WriteLine(string3.ToLower(CultureInfo.CurrentCulture));
        }
    }
}

Example showing formatted output

The following example shows the effect of current culture on the default IFormatProvider that is selected by the DateTime type.

public class IFormatProviderTest
{
    public static void Main1304()
    {
        string dt = "6/4/1900 12:15:12";

        // The default behavior of DateTime.Parse is to use
        // the current culture.

        // Violates rule: SpecifyIFormatProvider.
        DateTime myDateTime = DateTime.Parse(dt);
        Console.WriteLine(myDateTime);

        // Change the current culture to the French culture,
        // and parsing the same string yields a different value.

        Thread.CurrentThread.CurrentCulture = new CultureInfo("Fr-fr", true);
        myDateTime = DateTime.Parse(dt);

        Console.WriteLine(myDateTime);
    }
}

This example produces the following output:

6/4/1900 12:15:12 PM
06/04/1900 12:15:12

See also