C＃-在“封闭”局部范围内使用变量？

Question

I am trying to add some new features to a C# application- in particular, trying to replicate some of its behavior, but inside a web browser, rather than in the application, as it currently is.

I am trying to call a method that has been defined in the Browser.cs class from inside a method in the MainWindow.cs class.

The method is defined in Browser.cs with:

public partial class Browser : Form{
    public Browser(){
        ...
    }
    public void Browser_Load(object sender, EventArgs e){
        webKitBrowser1.Navigate("https://google.com");
    }
    ...
}

I am then trying to call it from MainWindow.cs as follows:

public partial class MainWindow : Window{
    ...
    public MainWindow(){
        ...
        Browser mBrowser = new Browser();
        Object sender = new Object();
        EventArgs e = new EventArgs();
        mBrowser.Browser_Load(sender, e);
        ...
    }
    ...
}

But, I'm getting a compile error that says:

A local or parameter named 'e' cannot be declared in this scope because that name is used in an enclosing local scope to define a local or parameter

What does this mean? I've never come across this error before- I am using the variable inside the same scope as where it has been declared- what does it mean by 'enclosing local scope'? Is that because I'm using e inside the parenthesis for the method call to mBrowser.Browser_Load(sender, e) ?

Surely, since the call to this method is inside the same scope as where I've defined e , it shouldn't be an issue of scope?

I did try performing the call with:

mBrowser.Browser_Load(sender, EventArgs e);

but this gave me a compile error saying:

'EventArgs' is a type, which is not valid in the given context.

Can anyone point out what I'm doing wrong here, and what I should be doing to be able to call this method correctly?

Answer 1

The error is pretty clear, you have already defined e named variable in your scope, (Probably in the part of code that you haven't shown) .

But more importantly, you shouldn't be calling the Load event like that, instead extract the functionality in a separate method and call the method from your Load event and other places.

Like:

public void SomeMethodToBeCalledOnLoad()
{
    webKitBrowser1.Navigate("https://google.com");
}

public void Browser_Load(object sender, EventArgs e)
{
    SomeMethodToBeCalledOnLoad();
}

public MainWindow(){
    ...
    Browser mBrowser = new Browser();
    Object sender = new Object();
    EventArgs e = new EventArgs();
    SomeMethodToBeCalledOnLoad();//here
    ...
}

Answer 2

You already have a variable named e in the scope.

try to call your method like this

mBrowser.Browser_Load(this, EventArgs.Empty);

and the error should go.