请参阅以下代码:
public class GenericTest2
{
public class MyGenericClass<T, U, V, W>
where T : class
where U : new()
where V : struct
where W : System.IO.StringWriter
{
}
public static void Test()
{
Assembly a = Assembly.GetAssembly(typeof(GenericTest));
foreach (Type t in a.GetTypes()) {
Console.Out.WriteLine(t.FullName);
if (t.IsGenericType) {
Console.Out.WriteLine("\tIsGeneric!");
foreach (Type parm in t.GetGenericArguments()) {
Console.Out.WriteLine("\tGeneric parameter: " + parm.Name);
Type[] constraints = parm.GetGenericParameterConstraints();
for (int i = 0; i < constraints.Length; i++) {
Console.Out.WriteLine("\t\t constraint " + i + ": name = " + constraints[i].Name);
Console.Out.WriteLine("\t\t constraint " + i + ": fullname = " + constraints[i].FullName);
}
}
}
}
}
}
此代码将输出如下内容:
ProcessCSharpAssemblies.Program
ProcessCSharpAssemblies.GenericTest2
ProcessCSharpAssemblies.GenericTest2+MyGenericClass`4
IsGeneric!
Generic parameter: T
Generic parameter: U
Generic parameter: V
constraint 0: name = ValueType
constraint 0: fullname = System.ValueType
Generic parameter: W
constraint 0: name = StringWriter
constraint 0: fullname = System.IO.StringWriter
约束class
和new()
似乎不是由parm.GetGenericParameterConstraints()
返回的。尽管 T
和 U
有限制,但 parm.GetGenericParameterConstraints()
不返回数据。
问:如何使用反射检查此类约束?
最佳答案
您要查找的约束可以通过查看 GenericParameterAttributes 找到类型
。
var gpa = parm.GenericParameterAttributes;
var constraints = gpa & GenericParameterAttributes.SpecialConstraintMask;
if ((constraints & GenericParameterAttributes.DefaultConstructorConstraint) != 0)
{
// yippie!
}
关于c# - 如何使用反射分析 C# 中的特殊类型约束?,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/33762226/