[英]Does Enum.GetValues() use reflection?
Enum.GetValues()是否使用反射?
我不认为它会,因为在编译时它应该能够获取可能的值列表并存储它们。 但我不知道这是不是真的。
我认为应该。 以下是完成工作的代码
// This will return enumValues and enumNames sorted by the values.
private void GetEnumData(out string[] enumNames, out Array enumValues)
{
Contract.Ensures(Contract.ValueAtReturn<String[]>(out enumNames) != null);
Contract.Ensures(Contract.ValueAtReturn<Array>(out enumValues) != null);
FieldInfo[] flds = GetFields(BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Static);
object[] values = new object[flds.Length];
string[] names = new string[flds.Length];
for (int i = 0; i < flds.Length; i++)
{
names[i] = flds[i].Name;
values[i] = flds[i].GetRawConstantValue();
}
// Insertion Sort these values in ascending order.
// We use this O(n^2) algorithm, but it turns out that most of the time the elements are already in sorted order and
// the common case performance will be faster than quick sorting this.
IComparer comparer = Comparer.Default;
for (int i = 1; i < values.Length; i++)
{
int j = i;
string tempStr = names[i];
object val = values[i];
bool exchanged = false;
// Since the elements are sorted we only need to do one comparision, we keep the check for j inside the loop.
while (comparer.Compare(values[j - 1], val) > 0)
{
names[j] = names[j - 1];
values[j] = values[j - 1];
j--;
exchanged = true;
if (j == 0)
break;
}
if (exchanged)
{
names[j] = tempStr;
values[j] = val;
}
}
enumNames = names;
enumValues = values;
}
注意FieldInfo [] flds = GetFields(BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Static); 线。 它看起来真的像反射法。 GetFields方法是抽象的
abstract public FieldInfo[] GetFields(BindingFlags bindingAttr);
所以我不确定如何为枚举实现它。
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