I am still pretty new to C# and am having a difficult time getting used to it compared to C/CPP.
How do you exit a function on C# without exiting the program like this function would?
if (textBox1.Text == "" || textBox1.Text == String.Empty || textBox1.TextLength == 0) textBox3.Text += "[-] Listbox is Empty!!!!\r\n"; System.Environment.Exit(0); This will not allow return types and if left alone it will keep going on through the function unstopped. Which is undesirable.
There are two ways to exit a method early (without quitting the program):
return keyword.Exceptions should only be used for exceptional circumstances - when the method cannot continue and it cannot return a reasonable value that would make sense to the caller. Usually though you should just return when you are done.
If your method returns void then you can write return without a value:
return; Specifically about your code:
You should also use curly braces when you write an if statement so that it is clear which statements are inside the body of the if statement:
if (textBox1.Text == String.Empty) { textBox3.Text += "[-] Listbox is Empty!!!!\r\n"; } return; // Are you sure you want the return to be here?? If you are using .NET 4 there is a useful method that depending on your requirements you might want to consider using here: String.IsNullOrWhitespace.
Environment.Newline instead of "\r\n".
string.IsNullOrEmpty (pre .Net 4 shout-out - which, of course does not detect whitespace-only strings). Sadly, not all of us can use 4.0, yet.
In addition to Mark's answer, you also need to be aware of scope, which (as in C/C++) is specified using braces. So:
if (textBox1.Text == "" || textBox1.Text == String.Empty || textBox1.TextLength == 0) textBox3.Text += "[-] Listbox is Empty!!!!\r\n"; return; will always return at that point. However:
if (textBox1.Text == "" || textBox1.Text == String.Empty || textBox1.TextLength == 0) { textBox3.Text += "[-] Listbox is Empty!!!!\r\n"; return; } will only return if it goes into that if statement.
I would use return null; to indicate that there is no data to be returned
The basic problem here is that you are mistaking System.Environment.Exit for return.
@John, Earlz and Nathan. The way I learned it at uni is: functions return values, methods don't. In some languages the syntax is/was actually different. Example (no specific language):
Method SetY(int y) ... Function CalculateY(int x) As Integer ... Most languages now use the same syntax for both versions, using void as a return type to say there actually isn't a return type. I assume it's because the syntax is more consistent and easier to change from method to function, and vice versa.
If the function is a void, ending the function will return. Otherwise, you need to do an explicit return someValue. As Mark mentioned, you can also throw an exception.
