Register the file type and associate the program (3)

Double-click a txt file to open it in notepad, because the txt file is associated with the Notepad program.

If you want to customize the file type, you can directly call your program and open it by double-clicking it? OK. First, we can find the first issue and see the following line of code:

Registry.SetValue(, , );

When you double-click the D: \ bin \ a. guo file, it is equivalent to executing the command line:

D:\bin\Guo.exe “D:\bin\a.guo”

D: \ bin \ a.guopassed the command line to the guo.exe program.

But how does the exe program accept this command line parameter?

In VS, If you create a new "console Program", there will be such a method in the automatically created Program. cs.

  Main([] args)

Args is the command line parameter. In the following example, args [0] is "D: \ bin \ a. guo ";

However, when you create a "Windows form application", you will find that the Main in Program is like this.

  Main()

Args is gone! Don't worry. Just change Main () to Main (string [] args.

In addition, args is not null here. If there is no parameter, It is args. Length = 0;

 

Sometimes, our program imposes format restrictions on command line parameters. For example, it may be like this to indicate the input file:

D:\bin\Guo.exe –i “D:\bin\a.guo”

This method of using a "key-Value Pair" as a parameter is very common in practice, because it does not need to limit the order of parameters, it is also easy to remember; for such a form, you only need to change the above command content to "D: \ bin \ Guo.exe-I \" % 1;

However, there are two scenarios for this method: drag the file to the guo.exe file and release it. In the open-ended documentation, select to use the guo.exe file to open it;

In both cases, Windows will execute the following command line to open the exe:

D: \ bin \ Guo.exe "file path"

The-I parameter is not available. It depends on your own.