如何獲得Action委托調用的名稱/詳細信息？

Question

我正在測試一些我在一些計時和記錄語句中包裝的類似方法調用的性能。 我通過動作委托參數傳遞這些方法。

有什么方法可以打印有關呼叫的詳細信息？

例如：

var httpResult = TestService(() => serviceHttp.Search(criteria));
var tcpResult = TestService(() => serviceTcp.Search(criteria));
var localResult = TestService(() => servicelocal.Search(criteria));

...

private static double TestService(Action serviceOperation)
{
    const int iterations = 15;
    ...

    for (var i = 0; i < iterations; i++)
    {
        var watch = Stopwatch.StartNew();

        ...

        Console.WriteLine(string.Format("{0} ElapsedMilliseconds={1}", ????, watch.ElapsedMilliseconds));
         // Ideally this would print something like "serviceTcp.DoStuff(...) ElapsedMilliseconds=313"
    }

    ...
}

Answer 1

將您的測試方法聲明更改為

private static double TestService(Expression<Action> expression)

調用表達式對象的Compile方法以獲取測試方法：

var serviceOperation = expression.Compile();

Expression對象可以提供有關方法調用的大量信息，您可以從以下內容開始：

private static string GetMethodCallDescription(Expression<Action> expression)
{
    var mce = (MethodCallExpression)expression.Body;
    var method = mce.Method;
    var sb = new StringBuilder();
    sb.Append(method.DeclaringType.Name);
    sb.Append(".");
    sb.Append(method.Name);
    sb.Append("(");
    bool firstarg = true;
    foreach(var arg in mce.Arguments)
    {
        if(!firstarg)
        {
            sb.Append(", ");
        }
        else
        {
            firstarg = false;
        }
        sb.Append(arg.ToString());
    }
    sb.Append(")");
    return sb.ToString();
}

Answer 2

您可以在不使用表達式樹的情況下完成此操作。 只需更改TestService的簽名即可分別采取操作和參數，然后使用Delegate.Target和Delegate.Method屬性獲取類型和方法：

var httpResult = TestService(serviceHttp.Search, criteria);
var tcpResult = TestService(serviceTcp.Search, criteria);
var localResult = TestService(servicelocal.Search, criteria);

...

private static double TestService<T>(Action<T> serviceOperation, T parameter)
{
    const int iterations = 15;
    ...

    for (var i = 0; i < iterations; i++)
    {
        var watch = Stopwatch.StartNew();

        ...

        string typeName = serviceOperation.Method.IsStatic
                          ? serviceOperation.Method.DeclaringType.Name
                          : serviceOperation.Target.GetType().Name;
        string methodName = serviceOperation.Method.Name;
        Console.WriteLine(string.Format("{0}.{1} ElapsedMilliseconds={2}", typeName, methodName, watch.ElapsedMilliseconds));
         // Ideally this would print something like "serviceTcp.DoStuff(...) ElapsedMilliseconds=313"
    }

    ...
}