C# 如何通过反射获得一个类型的所有常量？
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原文地址: http://stackoverflow.com/questions/10261824/
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How can I get all constants of a type by reflection?
提问by masoud ramezani
How can I get all constants of any type using reflection?
如何使用反射获取任何类型的所有常量？
采纳答案by gdoron is supporting Monica
Though it's an old code:
虽然这是一个旧代码：
private FieldInfo[] GetConstants(System.Type type)
{
ArrayList constants = new ArrayList();
FieldInfo[] fieldInfos = type.GetFields(
// Gets all public and static fields
BindingFlags.Public | BindingFlags.Static |
// This tells it to get the fields from all base types as well
BindingFlags.FlattenHierarchy);
// Go through the list and only pick out the constants
foreach(FieldInfo fi in fieldInfos)
// IsLiteral determines if its value is written at
// compile time and not changeable
// IsInitOnly determines if the field can be set
// in the body of the constructor
// for C# a field which is readonly keyword would have both true
// but a const field would have only IsLiteral equal to true
if(fi.IsLiteral && !fi.IsInitOnly)
constants.Add(fi);
// Return an array of FieldInfos
return (FieldInfo[])constants.ToArray(typeof(FieldInfo));
}
You can easily convert it to cleaner code using generics and LINQ:
您可以使用泛型和 LINQ 轻松将其转换为更清晰的代码：
private List<FieldInfo> GetConstants(Type type)
{
FieldInfo[] fieldInfos = type.GetFields(BindingFlags.Public |
BindingFlags.Static | BindingFlags.FlattenHierarchy);
return fieldInfos.Where(fi => fi.IsLiteral && !fi.IsInitOnly).ToList();
}
Or with one line:
或者用一行：
type.GetFields(BindingFlags.Public | BindingFlags.Static |
BindingFlags.FlattenHierarchy)
.Where(fi => fi.IsLiteral && !fi.IsInitOnly).ToList();
回答by Reza Bayat
Use property.GetConstantValue()to get value.
使用property.GetConstantValue()中获取价值。
回答by bytedev
As Type extensions:
作为类型扩展：
public static class TypeExtensions
{
public static IEnumerable<FieldInfo> GetConstants(this Type type)
{
var fieldInfos = type.GetFields(BindingFlags.Public | BindingFlags.Static | BindingFlags.FlattenHierarchy);
return fieldInfos.Where(fi => fi.IsLiteral && !fi.IsInitOnly);
}
public static IEnumerable<T> GetConstantsValues<T>(this Type type) where T : class
{
var fieldInfos = GetConstants(type);
return fieldInfos.Select(fi => fi.GetRawConstantValue() as T);
}
}
回答by BCA
If you would like to get the valuesof all constants of a specific type, from the target type, here is an extension method (extending some of the answers on this page):
如果您想从目标类型中获取特定类型的所有常量的值，这里是一个扩展方法（扩展此页面上的一些答案）：
public static class TypeUtilities
{
public static List<T> GetAllPublicConstantValues<T>(this Type type)
{
return type
.GetFields(BindingFlags.Public | BindingFlags.Static | BindingFlags.FlattenHierarchy)
.Where(fi => fi.IsLiteral && !fi.IsInitOnly && fi.FieldType == typeof(T))
.Select(x => (T)x.GetRawConstantValue())
.ToList();
}
}
Then for a class like this
然后对于这样的班级
static class MyFruitKeys
{
public const string Apple = "apple";
public const string Plum = "plum";
public const string Peach = "peach";
public const int WillNotBeIncluded = -1;
}
You can obtain the stringconstant values like this:
您可以string像这样获得常量值：
List<string> result = typeof(MyFruitKeys).GetAllPublicConstantValues<string>();
//result[0] == "apple"
//result[1] == "plum"
//result[2] == "peach"
