Errors, exceptions, try-catch-finally, throw

A script with errors can't run. Errors must be fixed.

print.it(1) //error, no semicolon
print.it(u); //error, u does not exist

Exceptions occur when something fails at run time. Then the script ends or jumps to a catch part of the nearest try-catch statement that embraces that code. More info.

print.it(1);
try {
	var w = wnd.find(0, "* - Notepadd");
	print.it(2);
}
catch {
	print.it("exception");
	return; //remove this, and the script will continue at print.it(3);
	//throw; //add this instead of return, and the script will end like without try/catch
	//throw new InvalidOperationException("message"); //or throw another exception
}
print.it(3);

Can get exception info.

try { run.it("notepad11.exe"); }
catch (Exception e) { print.it(e); }
print.it("continue");

Can differently handle exceptions of different types. Can use when.

string text = null;
try { text = File.ReadAllText(@"D:\file45678"); }
catch (FileNotFoundException) { } //continue
catch (Exception e) when (e is not ArgumentException) { //handle all other exceptions except ArgumentException
	print.it(e.ToStringWithoutStack());
	return;
}
print.it(text ?? "file not found");

Can use try-finally and try-catch-finally. More info. The finally code runs when the try code is leaved in whatever way (finished, exception, return, goto, etc).

print.it(1);
try {
	run.it("notepad22.exe");
	print.it(2);
	if (keys.isCapsLock) return;
}
//catch { print.it("exception"); } //optional. Try to uncomment this and observe the difference.
finally { print.it("finally"); }
print.it(3);

Note: The finally code does not run if Environment.Exit or some other function terminates the process.

With disposable objects instead of try-finally-Dispose can be used the using statement.

To throw exceptions use the throw statement.

Func1(1);
Func1(-1);

void Func1(int i) {
	if (i < 0) throw new ArgumentException("Can't be negative", nameof(i));
	if (keys.isCapsLock) throw new InvalidOperationException("CapsLock");
	print.it(i);
}

Two ways to insert try code quickly:

• Type tryc and select trySnippet.
• Click or select code, and use menu Edit > Selection > Surround.