C# .NET 4.0 中反射的最佳替代品

本文关键字：反射的 最佳 替代品 NET | 更新日期: 2023-09-27 18:31:09

我面临着以下通过反射检索数据的代码：

public object GetValue(object source)
{
    if (Member == null) return Argument;
    try
    {
        object[] argList = (Argument == null ? null : new object[] { Argument });
        if (Member is PropertyInfo) return ((PropertyInfo)Member).GetValue(source, argList);
        if (Member is MethodInfo) return ((MethodInfo)Member).Invoke(source, argList);
        if (Member is FieldInfo) return ((FieldInfo)Member).GetValue(source);
        throw new Exception("Unknown member type: " + Member);
    }
    catch (Exception ex)
    {
        throw new Exception("Could not get value " + Member.Name + " from " + source + " with " + Argument, ex);
    }
}

然而，这非常慢，我正在考虑用更快的东西替换反射，也许是代表们？但是，我不确定代表是最佳选择，或者在这种情况下如何实现它。我正在运行.NET 4.0。任何建议不胜感激！

C# .NET 4.0 中反射的最佳替代品

这有点快

static Func<object, object[], object> BuildCaller(MethodInfo method)
{
    var obj = Expression.Parameter(typeof(object));
    var pars = Expression.Parameter(typeof(object[]));
    var pars2 = method.GetParameters();
    var casted = new Expression[pars2.Length];
    for (int i = 0; i < pars2.Length; i++)
    {
        casted[i] = Expression.Convert(Expression.ArrayAccess(pars, Expression.Constant(i)), pars2[i].ParameterType);
    }
    var call = Expression.Call(Expression.Convert(obj, method.DeclaringType), method, casted);
    var cast = Expression.Convert(call, typeof(object));
    var lamdba = Expression.Lambda<Func<object, object[], object>>(cast, obj, pars);
    return lamdba.Compile();
}
static Func<object, object[], object> BuildCaller(FieldInfo field)
{
    var obj = Expression.Parameter(typeof(object));
    var pars = Expression.Parameter(typeof(object[]));
    var call = Expression.Field(Expression.Convert(obj, field.DeclaringType), field);
    var cast = Expression.Convert(call, typeof(object));
    var lamdba = Expression.Lambda<Func<object, object[], object>>(cast, obj, pars);
    return lamdba.Compile();
}
static Func<object, object[], object> BuildCaller(PropertyInfo property)
{
    var obj = Expression.Parameter(typeof(object));
    var pars = Expression.Parameter(typeof(object[]));
    var pars2 = property.GetIndexParameters();
    var casted = new Expression[pars2.Length];
    for (int i = 0; i < pars2.Length; i++)
    {
        casted[i] = Expression.Convert(Expression.ArrayAccess(pars, Expression.Constant(i)), pars2[i].ParameterType);
    }
    var call = Expression.Property(Expression.Convert(obj, property.DeclaringType), property, casted);
    var cast = Expression.Convert(call, typeof(object));
    var lamdba = Expression.Lambda<Func<object, object[], object>>(cast, obj, pars);
    return lamdba.Compile();
}

我创建了一个预缓存该方法的委托（通过 Expression s）。如果Arguments是"固定的"，你可以更进一步，甚至预缓存它们的转换（就像每次调用该方法时都会完成转换一样）

这是方法的一个示例。对于属性和字段，它是相似的（对于字段，它甚至更容易）。

和一个例子

var fun = BuildCaller(typeof(MyClass).GetMethod("MyMethod"));
var mc = new MyClass();
fun(mc, new object[] { 1, 2.0 });

您必须将fun与Method一起缓存

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