如何使用dll将消息发送到表单？

Question

I am developing an gui application in c# that uses a dll. This dll contains several common functions, like validation of properties.

However, I need to validate the properties of an object with a function like this:

public static bool validate(MyObject object)
{

  bool success = true;

  // some validation
  if(!valid(object.property))
  {
    // log to database, this works
    log("property is not valid"); // log to database, this works

    // how can I do this?
    sendMessageToForm("property is not valid");

    success = false;
  }

  return success;

}

Additionally, validate() must return a boolean value, not a string of messages

how can I send a message to a form through a dll?

Answer 1

您需要在项目中添加dll的引用，之后再在类中添加dll的名称空间，稍后再声明该类的对象并调用validate消息并传递用于validate的参数。

Answer 2

If what you have shown here is the code inside your dll, I'm assuming you want to update the form from inside your dll. The way to do that is for your dll class to publish an event, let's say ValidationError event, that will also carry with it as EventArgs the message you want to display on the form.

Then, on your form, where you instantiate the object from your dll class , you would also have to attach a listener for that event.

MyClassInDll myObject=new MyClassInDll();
myObject.ValidationError+=new EventHandler<ValidationErrorMessage>(YourMethodThatDisplaysTheMessagesOnTheForm);

Then you can use the object to call if (myObject.Validate(someOtherObject)) which will return a boolean , while still triggering the event that sends the error messages to your form.

Answer 3

public static bool validate(MyObject object, out message)

这将为您提供输出消息字符串，可以从调用validate的位置进行设置。