扩展“<"；以及“>"；System.Type的运算符

C#中没有"扩展运算符"。

至少有一个运算符参数必须是在中声明运算符的类型。

正如其他人所说，C#不支持扩展运算符。如果你需要这样做，那么你可以实现一个自定义类型，比如：

public class MyType : Type
{
    private Type internalType;
    public MyType(Type t)
    {
        internalType = t;
    }
    public static Boolean operator >(MyType t1, Type t2)
    {
        //TODO once it compiles
        return false;
    }
    public static Boolean operator <(MyType t1, Type t2)
    {
        //TODO once it compiles
        return true;
    }
    public override Assembly Assembly
    {
        get { return internalType.Assembly; }
    }
    public override string AssemblyQualifiedName
    {
        get { return internalType.AssemblyQualifiedName; }
    }
    public override Type BaseType
    {
        get { return internalType.BaseType; }
    }
    public override string FullName
    {
        get { return internalType.FullName; }
    }
    public override Guid GUID
    {
        get { return internalType.GUID; }
    }
    protected override TypeAttributes GetAttributeFlagsImpl()
    {
        return internalType.Attributes;
    }
    protected override ConstructorInfo GetConstructorImpl(BindingFlags bindingAttr, Binder binder, CallingConventions callConvention, Type[] types, ParameterModifier[] modifiers)
    {
        return internalType.GetConstructor(bindingAttr, binder, callConvention, types, modifiers);
    }
    public override ConstructorInfo[] GetConstructors(BindingFlags bindingAttr)
    {
        return internalType.GetConstructors(bindingAttr);
    }
    public override Type GetElementType()
    {
        return GetElementType();
    }
    public override EventInfo GetEvent(string name, BindingFlags bindingAttr)
    {
        return internalType.GetEvent(name, bindingAttr);
    }
    public override EventInfo[] GetEvents(BindingFlags bindingAttr)
    {
        return internalType.GetEvents(bindingAttr);
    }
    public override FieldInfo GetField(string name, BindingFlags bindingAttr)
    {
        return internalType.GetField(name, bindingAttr);
    }
    public override FieldInfo[] GetFields(BindingFlags bindingAttr)
    {
        return internalType.GetFields(bindingAttr);
    }
    public override Type GetInterface(string name, bool ignoreCase)
    {
        return internalType.GetInterface(name, ignoreCase);
    }
    public override Type[] GetInterfaces()
    {
        return internalType.GetInterfaces();
    }
    public override MemberInfo[] GetMembers(BindingFlags bindingAttr)
    {
        return internalType.GetMembers(bindingAttr);
    }
    protected override MethodInfo GetMethodImpl(string name, BindingFlags bindingAttr, Binder binder, CallingConventions callConvention, Type[] types, ParameterModifier[] modifiers)
    {
        return internalType.GetMethod(name, bindingAttr, binder, callConvention, types, modifiers);
    }
    public override MethodInfo[] GetMethods(BindingFlags bindingAttr)
    {
        return internalType.GetMethods(bindingAttr);
    }
    public override Type GetNestedType(string name, BindingFlags bindingAttr)
    {
        return internalType.GetNestedType(name, bindingAttr);
    }
    public override Type[] GetNestedTypes(BindingFlags bindingAttr)
    {
        return internalType.GetNestedTypes(bindingAttr);
    }
    public override PropertyInfo[] GetProperties(BindingFlags bindingAttr)
    {
        return internalType.GetProperties(bindingAttr);
    }
    protected override PropertyInfo GetPropertyImpl(string name, BindingFlags bindingAttr, Binder binder, Type returnType, Type[] types, ParameterModifier[] modifiers)
    {
        return internalType.GetProperty(name, bindingAttr, binder, returnType, types, modifiers);
    }
    protected override bool HasElementTypeImpl()
    {
        return internalType.HasElementType;
    }
    public override object InvokeMember(string name, BindingFlags invokeAttr, Binder binder, object target, object[] args, ParameterModifier[] modifiers, System.Globalization.CultureInfo culture, string[] namedParameters)
    {
        return internalType.InvokeMember(name, invokeAttr, binder, target, args, modifiers, culture, namedParameters);
    }
    protected override bool IsArrayImpl()
    {
        return internalType.IsArray;
    }
    protected override bool IsByRefImpl()
    {
        return internalType.IsByRef;
    }
    protected override bool IsCOMObjectImpl()
    {
        return internalType.IsCOMObject;
    }
    protected override bool IsPointerImpl()
    {
        return internalType.IsPointer;
    }
    protected override bool IsPrimitiveImpl()
    {
        return internalType.IsPrimitive;
    }
    public override Module Module
    {
        get { return internalType.Module; }
    }
    public override string Namespace
    {
        get { return internalType.Namespace; }
    }
    public override Type UnderlyingSystemType
    {
        get { return internalType.UnderlyingSystemType; }
    }
    public override object[] GetCustomAttributes(Type attributeType, bool inherit)
    {
        return internalType.GetCustomAttributes(attributeType, inherit);
    }
    public override object[] GetCustomAttributes(bool inherit)
    {
        return internalType.GetCustomAttributes(inherit);
    }
    public override bool IsDefined(Type attributeType, bool inherit)
    {
        return internalType.IsDefined(attributeType, inherit);
    }
    public override string Name
    {
        get { return internalType.Name; }
    }
}

或者，实现一个可以委托调用的自定义DynamicObject（C#4+）可能会更容易。

您可以在自己的类中重载运算符，但不能通过扩展方法在其他类中重载。

不能将运算符行为定义为扩展方法
您可以使用与DateTime处理Add()和Subtract()相同的方式来执行此操作，如果您不能修改类型实现，它们可以作为扩展方法来实现。

您也可以从类型继承（如果可能的话），并在那里定义运算符。