docs/csharp/language-reference/attributes/snippets/CallerInformation.cs - main - aprogrammer/dotnet-docs

docs/csharp/language-reference/attributes/snippets/CallerInformation.cs

73 строки2 KB

Bill Wagner

first draft of nameof updates (#29549)

15 июн 2022, 00:43

15 июн 2022, 00:4386ba43a

using System.Diagnostics;
using System.Runtime.CompilerServices;


namespace attributes;

internal class CallerInformation
{
    // <CallerFileMemberLine>
    public void DoProcessing()
    {
        TraceMessage("Something happened.");
    }

    public void TraceMessage(string message,
            [CallerMemberName] string memberName = "",
            [CallerFilePath] string sourceFilePath = "",
            [CallerLineNumber] int sourceLineNumber = 0)
    {
        Trace.WriteLine("message: " + message);
        Trace.WriteLine("member name: " + memberName);
        Trace.WriteLine("source file path: " + sourceFilePath);
        Trace.WriteLine("source line number: " + sourceLineNumber);
    }

    // Sample Output:
    //  message: Something happened.
    //  member name: DoProcessing
    //  source file path: c:\Visual Studio Projects\CallerInfoCS\CallerInfoCS\Form1.cs
    //  source line number: 31
    // </CallerFileMemberLine>

    // <InvokeTestCondition>
    public void Operation(Action func)
    {
        Utilities.ValidateArgument(nameof(func), func is not null);
        func();
    }
    // </InvokeTestCondition>


    public static class Utilities
    {
        // <TestCondition>
        public static void ValidateArgument(string parameterName, bool condition, [CallerArgumentExpression("condition")] string? message=null)
        {
            if (!condition)
            {
                throw new ArgumentException($"Argument failed validation: <{message}>", parameterName);
            }
        }
        // </TestCondition>
    }
}

public static class Extensions
{
    // <ExtensionMethod>
    public static IEnumerable<T> Sample<T>(this IEnumerable<T> sequence, int frequency, 
        [CallerArgumentExpression(nameof(sequence))] string? message = null)
    {
        if (sequence.Count() < frequency)
            throw new ArgumentException($"Expression doesn't have enough elements: {message}", nameof(sequence));
        int i = 0;
        foreach (T item in sequence)
        {
            if (i++ % frequency == 0)
                yield return item;
        }
    }
    // </ExtensionMethod>

}