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[英]Reflection - Getting the generic arguments from a System.Type instance
[英]How to I get reference to generic singleton instance using only System.Type/reflection
我創建了一個簡單的性能測試類,它是一個singlton,它使用泛型PerformanceTesting<T>.Instance
(完整的源代碼可在我的博客文章中找到,但它不是最新版本http://www.createdbyx.com/post/2013/03/27/Code-Snippets-12-%E2%80%93 -Performance-Testing.aspx )
這使開發人員可以使用他們更喜歡使用的東西作為訪問鍵,無論它是字符串,整數還是枚舉等。
因此,一切工作都很好,但是我試圖建立一個性能報告窗口,並且我希望能夠從所有實例化的singlton實例中收集性能數據,而不是PerformanceTesting<int> or PerformanceTesting<string>
等。
我認為可以做到這一點的唯一方法是使用反射。 我還應該提到PerformanceTesting類利用另一個類來跟蹤用作PerformanceTesting<T>
單例的訪問鍵的各種類型。
/// <summary>
/// Provides a lock object when a singleton reference need to be instantiated.
/// </summary>
private static object lockObject = new object();
/// <summary>
/// Gets a singleton instance of the <see cref="PerformanceTesting{T}"/> class.
/// </summary>
public static PerformanceTesting<T> Instance
{
get
{
if (singleton == null)
{
lock (lockObject)
{
singleton = new PerformanceTesting<T>();
PerformanceTestingTypes.Register<T>();
}
}
return singleton;
}
}
一個簡化的PerformanceTestingTypes類的簡化版本是...
public class PerformanceTestingTypes
{
private static PerformanceTestingTypes singleton;
private List<Type> types = new List<Type>();
public static PerformanceTestingTypes Instance
{
get
{
return singleton ?? (singleton = new PerformanceTestingTypes());
}
}
public static Type[] GetTypes()
{
var values = new Type[Instance.types.Count];
Instance.types.CopyTo(values, 0);
return values;
}
public static void Register<T>()
{
Instance.types.Add(typeof(T));
}
// can't return PerformanceTesting<T> because T is of System.Type not the actual accessor type.
public static PerformanceTesting<T> GetTesting<T>(T type)
{
var rootType = typeof(PerformanceTesting<>); // this is wrong but placed for example purposes!!!
var prop = rootType.GetProperty("Instance");
var reference = prop.GetGetMethod().Invoke(null, null);
return reference; // compile error because Invoke returns type System.Object
}
}
我正在使用此方法嘗試將結果報告給調試日志...
/// <summary>
/// If the PERFORMANCE symbol is available will report the performance metric information out to the console.
/// </summary>
public static void ReportPerformanceTimes()
{
var result = string.Empty;
foreach (var type in PerformanceTestingTypes.GetTypes())
{
var perf = PerformanceTestingTypes.GetTesting(type);
var keyNames = PerformanceTestingTypes.GetKeyNames(type);
foreach (var name in keyNames)
{
var key = PerformanceTestingTypes.ConvertKey(name, type);
result += string.Format("{0} - Total: {1}ms Average: {2} Count: {3}\r\n", name, perf.TotalMilliseconds(key), perf.AverageMilliseconds(key), perf.GetStartCount(key));
}
result += string.Format("Total Performance Times - Total: {0}ms", perf.TotalMilliseconds(perf.GetKeys()));
}
Debug.Log(result);
}
我遇到的問題在於PerformanceTestingTypes.GetTesting()方法內。 我需要僅使用System.Type返回對通用單例的特定實例的引用,該System.Type引用單例用作其訪問者鍵的實際類型。
var type = typeof(int); // the accessor key type that was used
// from the 'type' variable get a reference to singleton
var reference = PerformanceTesting<int>.Instance;
或換一種說法,如果我所擁有的只是一個變量“類型”(即引用int的System.Type),我將如何使用反射來獲取PerformanceTesting<int>
的類型。
從技術上講,我認為我可以嘗試在字符串內部創建並構建一個C#類,然后將該字符串編譯為內存中的程序集,然后調用該類以獲取對我所需的單例的引用,但是這似乎過頭了,我懷疑我可能以及投放時遇到相同或相似的問題。
這甚至可能嗎?還是我試圖做不可能的事情? 希望我的問題有道理。 我的大腦已決定對此進行休整。 :(
嘗試這個:
var performanceTestingType = typeof(PerformanceTesting<>);
Type[] typeArgs = { typeof(int) };
var genericType = performanceTestingType.MakeGenericType(typeArgs);
object performanceTestingOfTypeInt = Activator.CreateInstance(genericType);
MSDN文章在這里
對於那些訪問此頁面並尋找相似答案的人,我要感謝jaywayco的答案,以其為最終實現目標的方法。
private void DrawPerformanceMetricsFlatList()
{
foreach (var type in PerformanceTestingTypes.GetTypes())
{
var performanceTestingType = typeof(PerformanceTesting<>);
Type[] typeArgs = { type };
var genericType = performanceTestingType.MakeGenericType(typeArgs);
var data = genericType.GetProperty("Instance", BindingFlags.GetProperty | BindingFlags.Static | BindingFlags.Public).GetGetMethod().Invoke(null, null);
var totalMilli = data.GetType().GetMethod("TotalMilliseconds", new[] { type });
var avgMilli = data.GetType().GetMethod("AverageMilliseconds", new[] { type });
var totalTicks = data.GetType().GetMethod("TotalTicks", new[] { type });
var avgTicks = data.GetType().GetMethod("AverageTicks", new[] { type });
var startCount = data.GetType().GetMethod("GetStartCount", new[] { type });
var fromConverter = data.GetType().GetProperty("ConvertFromStringCallback");
// var toConverter = data.GetType().GetProperty("ConvertToStringCallback", new[] { type });
var func = fromConverter.GetGetMethod().Invoke(data, null);
var invoker = func.GetType().GetMethod("Invoke");
var keyNames = PerformanceTestingTypes.GetKeyNames(type);
switch (this.sortIndex)
{
case 1:
keyNames = keyNames.OrderBy(x => x).ToArray();
break;
case 2:
keyNames = keyNames.OrderByDescending(x => totalTicks.Invoke(data, new[] { invoker.Invoke(func, new[] { x }) })).ToArray();
break;
case 3:
keyNames = keyNames.OrderByDescending(x => avgTicks.Invoke(data, new[] { invoker.Invoke(func, new[] { x }) })).ToArray();
break;
case 4:
keyNames = keyNames.OrderByDescending(x => startCount.Invoke(data, new[] { invoker.Invoke(func, new[] { x }) })).ToArray();
break;
}
ControlGrid.DrawGenericGrid((items, index, style, options) =>
{
var value = items[index];
var selected = GUILayout.Toggle(this.selectedIndex == index, value, style);
if (selected)
{
this.selectedIndex = index;
var key = invoker.Invoke(func, new[] { value });
this.performanceData = string.Format("{0}\r\nTotal: {1}ms ({4} ticks)\r\nAverage: {2}ms ({5} ticks)\r\nCount: {3}\r\n", value,
totalMilli.Invoke(data, new[] { key }),
avgMilli.Invoke(data, new[] { key }),
startCount.Invoke(data, new[] { key }),
totalTicks.Invoke(data, new[] { key }),
avgTicks.Invoke(data, new[] { key }));
}
return value;
}, keyNames, 1, GUI.skin.button);
}
}
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