使用ThreadStatic属性提供线程安全的数据访问

ThreadStatic是一个C#属性，用于为每个线程提供独立的静态字段。使用它可以让每个线程拥有该字段的独立副本，避免线程之间的共享

用途

线程独立数据：每个线程有独立的数据副本，彼此不干扰
性能优化：在多线程环境中减少锁的使用，因为每个线程访问自己的数据
线程安全：自动提供线程安全的数据访问

举例

using System;
using System.Threading.Tasks;

class Program
{
    [ThreadStatic]
    private static int _threadSpecificData;

    static async Task Main()
    {
        var task1 = Task.Run(() =>
        {
            _threadSpecificData = 42;
            Console.WriteLine($"Task 1: {_threadSpecificData}");
        });

        var task2 = Task.Run(() =>
        {
            _threadSpecificData = 84;
            Console.WriteLine($"Task 2: {_threadSpecificData}");
        });

        await Task.WhenAll(task1, task2);
    }
}

运行结果：

Task 1: 42
Task 2: 84

实际项目应用

以下是Dynamo项目TraceUtils类

using System;
using System.Threading.Tasks;
/// <summary>
/// Utility class to Get/Set TraceData
/// </summary>
public static class TraceUtils
{
    internal const string __TEMP_REVIT_TRACE_ID = "{0459D869-0C72-447F-96D8-08A7FB92214B}-REVIT";
    // ReSharper restore InconsistentNaming

    [ThreadStatic] private static Dictionary<string, string> _localStorageSlot;

    internal static Dictionary<string, string> LocalStorageSlot
    {
        get
        {
            return _localStorageSlot ?? (_localStorageSlot = new Dictionary<string, string>());
        }
        set
        {
            _localStorageSlot = value;
        }
    }

    /// <summary>
    /// Returns a list of the keys bound to trace elements
    /// This should be extracted from the attribute on the methods
    /// </summary>
    /// <returns></returns>
    internal static List<String> TEMP_GetTraceKeys()
    {
        //TODO:Luke Extract this from RequiresTraceAttribute

        return new List<string>() { __TEMP_REVIT_TRACE_ID };
    }

    /// <summary>
    /// Clear a specific key
    /// </summary>
    /// <param name="key"></param>
    internal static void ClearTLSKey(string key)
    {
        LocalStorageSlot.Remove(key);
    }

    /// <summary>
    /// Clear the named slots for all the know keys
    /// </summary>
    internal static void ClearAllKnownTLSKeys()
    {
        LocalStorageSlot.Clear();
    }

    /// <summary>
    /// Returns the data that is bound to a particular key
    /// </summary>
    /// <param name="key"></param>
    /// <returns></returns>
    public static string GetTraceData(string key)
    {
        string data;
        if (!LocalStorageSlot.TryGetValue(key, out data))
        {
            return null;
        }
        else
        {
            return data;
        }
    }

    /// <summary>
    /// Set the data bound to a particular key
    /// </summary>
    /// <param name="key"></param>
    /// <param name="value"></param>
    public static void SetTraceData(string key, string value)
    {
        if (LocalStorageSlot.ContainsKey(key))
        {
            LocalStorageSlot[key] = value;
        }
        else
        {
            LocalStorageSlot.Add(key, value);
        }
    }
}
class Program
{
    static async Task Main(string[] args)
    {
        var task1 = Task.Run(() =>
        {
            TraceUtils.SetTraceData("Task1Key", "Task1Data");
            Console.WriteLine($"Task 1: {TraceUtils.GetTraceData("Task1Key")}");
        });

        var task2 = Task.Run(() =>
        {
            TraceUtils.SetTraceData("Task2Key", "Task2Data");
            Console.WriteLine($"Task 2: {TraceUtils.GetTraceData("Task2Key")}");
        });

        await Task.WhenAll(task1, task2);
    }
}