an external cancel signal, and exiting if there is such a signal. As you can see, the thread itself actually plays a major role in the mechanism of properly stopping threads. The work code in the example is simple but sufficient to illustrate the problem. More complex computational work should also be done in such a way as to properly and correctly handle the exit.The key type in collaborative cancellation is CancellationTokenSource. It has a key property Token,token is a value type named Cance
look at the reciprocal conversions of nullable types and primitive types. The primitive type provides an implicit conversion of its corresponding nullable type, as follows: int NULL ; int 0 ; In turn, nullable types are not implicitly convertible to the corresponding primitive type, and the correct conversion form is as follows: int 123 ; int J; if (I.hasvalue) { = i.value; } Else { 0; But does this code look a bit cumber
the toboolean above, and if this type of transformation is not supported, a InvalidCastException should be thrown instead of a notimplementedexception.System.bitconverter provides a way to convert between primitive types and byte arrays, which is not discussed here.4. Using CLR-supported transformationsThe transformation that the CLR supports, that is, upstream and downstream transformation. This concept is first proposed in Java, which is actually the conversion between the base class and the
: getemployeehanlder Getamanager; GetemployeehanlderTo get the above code to compile, you also need to specify the OUT keyword for the generic parameter in the delegate: Public Delegate T getemployeehanlder out t> (string name);Unless the delegate declaration is certainly not used for variability, specifying the OUT keyword for a generic parameter in a delegate expands the application of the delegate and is recommended to be used forever in the actual encoding process. In f
delegate chain to null:null;2) fileuploaded can be called externally, such as:F1. Fileuploaded (ten);This should not be allowed, because when the caller is notified, it should be the Fileuploader class's own responsibility, rather than the caller itself to decide. The event keyword is raised in this case, and it is protected by the delegate.Will Public Fileuploadedhandler fileuploaded;Switch Public Event Fileuploadedhandler fileuploaded;In this way, several of the above mentioned situations are
instance void[mscorlib]system.idisposable::D ispose ()il_0034: NOP il_0035: endfinally } //End Handler il_0036: NOP il_0037: Pager Int32[Mscorlib]system.console::read ()il_003c: Pop il_003d: ret} //end of Method Program::mainViewing the IL code shows that the get_current () and MoveNext () methods are still called by the runtime.After the MoveNext () method is called, if the result is true, jump to the beginning of the loop. In fact, the Foreach loop and the while loop are
implemented. In order for a field to support thread safety, it can only be done by the caller itself.3) The property is supported by the VS compiler, and it also has the ability to implement automatic attributes. The features of automatic attributes are widely used in LINQ, especially in anonymous classes, which can only implement read-only automatic attributes, not fields.4) from a design perspective, the object-oriented perspective, the exposed fields should also use attributes. Changes the s
(); } class A:isample { private b b; Public void MethodA () { b.methodb (); } } class B { isample A; Public void MethodB () { A.methoda (); } }Interface Isample regulates the behavior of type A, while having type a inherit from Isample. In type B, we program the interface, that is, field A in B is no longer a type, but instead modifies it to the isample type.In general, there should be no b
voidTaskscheduler_unobservedtaskexception (Objectsender, Unobservedtaskexceptioneventargs e) { foreach(Exception Iteminche.exception.innerexceptions) {Console.WriteLine ("Exception type: {0}{1} from: {2}{3} exception content: {4}", item. GetType (), Environment.NewLine, item. Source, Environment.NewLine, item. Message); } //identifies the exception as having been observede.setobserved (); } The result of this code run does not output exception information, because there is no gar
; (Delegate(intIintj) {returni +J; }); Actionstring> print=Newactionstring> (Delegate(stringmsg) {Console.WriteLine (msg); });Print (Add (1, 2). ToString ());With anonymous methods, we don't need to declare two methods outside of the main method, so that all code can be written directly in the work method of main, without affecting the clarity of the code. In fact, all of the lines of code that are not more than 3 lines (provided that it is not reused) are recommended to be
want to be deserialized into personanother. The type Personanother is simple, and it doesn't even need to know who will be deserialized into it, and it doesn't need to do any special processing.ISerializable interface This feature is very important, if used properly, in the version upgrade, it can handle the problem of the type because of the changes in the field.Turn from: 157 recommendations for writing high-quality code to
") throw; } }The record exception is also captured at the higher call stack location: Internal void Methodhigh () { try { methodlow (); } Catch (someexception) { logger.write (" exception someexception occurs ") } }This will cause the record to recur. In the case of low call stacks, exceptions are often caught and cannot be processed completely.
instance object. We cannot bypass the instance object and invoke the instance method directly from the type itself. So, from a design point of view, if a method is only related to the type itself, then it should be designed as a static method, and if it is related to an instance object of the type, it should be designed as an instance method.Static methods are misunderstood by many people: static methods are naturally synchronous methods. Even programmers with a certain amount of development ex
(Nativeresource! =IntPtr.Zero) {Marshal.freehglobal (Nativeresource); Nativeresource=IntPtr.Zero; } //let the type know that they have been releaseddisposed =true; } Public voidSamplepublicmethod () {if(disposed) {Throw NewObjectDisposedException ("SampleClass","SampleClass is disposed"); } //omitted } } classanotherresource:idisposable { Public voidDispose () {}}If you do not provide this protected virtual method for your class, it is likely that you w
efficiency problem of returning 3 or 2 is not obvious, but putting the application in the Internet system and reducing the amount of traffic in each place will give us a significant performance boost.In fact, the difference between the delay evaluation and the active evaluation should be carefully understood, and the results will be realized in the application: otherwise, there will be some unexpected bugs.Turn from: 157 recommendations for writing high-qua
:
The extension method must be in a static class, and the class cannot be a nested class;
The extension method must be static;
The first parameter of an extension method must be the type to be extended, and the This keyword must be added;
Extended properties, events are not supported.
It is important to note that the extension method can also extend the interface. This makes the interface appear to be extensible as well. This feature of extension methods is widely used
resource need to be cleaned manually? You might want to divide the types in C # into two categories, one inheriting the IDisposable interface, and one without inheritance. The former, temporarily known as the non-ordinary type, the latter is called the ordinary type. Non-trivial type because it contains an unmanaged resource, it needs to inherit the IDisposable interface, but this contains the type itself of the unmanaged resource, which is a managed resource. Therefore, a normal type in a mana
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