在我的对象C＃中异步传递参数

Question

I have got a button in windows form application c# code which calls a created object called capturer. My code is the following:

private void button1_Click(object sender, EventArgs e)
{
      obj = new Capturer(dirPath + name + "_" + surname, switcher);
}

The default value of switcher (boolean variable) is false. I want to change this value of switcher using the right click and pass it to the object real-time. I want the object to be updated every time the click is pressed. In order to detect mouse click events I have the following code:

 private void mouseClick1(object sender, MouseEventArgs e)
    {
        if (e.Button == MouseButtons.Right)
        {
            Trace.WriteLine("Mouse clicked");
            switcher = true; 
        }
    }

How can I pass the variable in my object asynchronously?

Answer 1

Creating a new object on every mouse click will not help performance. You might want to create a Capturer in the Form constructor, then call a method on it on a right mouse click.

The name Capturer suggests you're trying to implement an observer pattern, but that's not exactly what's happening here; the form is the observer here, and the Capturer should be responsible for your business logic - and have a name explaining its purpose.

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(unless your business case is capturing mouse clicks...)

Answer 2

There are a couple solutions to your problem. The easiest one ist to make switcher accessible outside of Capturer after creation. For instance you could turn it into a property:

public class Capturer
{
    public Capturer(string path, bool switcher)
    {
        Switcher = switcher;
        ...
     }

    public bool Switcher { get; set; }

    ...
}

Inside your click handler you set the Switcher value:

private void mouseClick1(object sender, MouseEventArgs e)
{
    if (e.Button == MouseButtons.Right)
    {
        Trace.WriteLine("Mouse clicked");
        obj.Switcher = true; 
    }
}

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In case you don't want to share the Capturer instance obj between button1_Click() and mouseClick1() you can also pass in a custom type into the Capturer constructor instead of a primitive value. If you save the reference to that type in your form you can change it anytime and your Capturer instance will pick up the changed value.

public class Switcher
{
    public bool Value { get; set; }
}

Your Capturer constructor will look like this:

public Capturer(string path, Switcher switcher)
{
    this.switcher = switcher;
    ...
}

Inside the Capturer make sure you always access the switcher value through the Switcher instance. Ie always use switcher.Value to get it.

You can create the Switcher instance inside your button handler...

private void button1_Click(object sender, EventArgs e)
{
    switcher = new Switcher();
    obj = new Capturer(dirPath + name + "_" + surname, switcher);
}

...and set it in your click handler:

private void mouseClick1(object sender, MouseEventArgs e)
{
    if (e.Button == MouseButtons.Right)
    {
        Trace.WriteLine("Mouse clicked");
        switcher.Value = true; 
    }
}

This way you only have to share the Switcher instance between you handlers, but not the Capturer instance. Which solution is better depends on the way you want to structure your application and which parts should be coupled and which should be decoupled.

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A third solution is to use a lambda, a delegate or an event.