Not all code paths return a value

Nikhil Bhivgade

public Boolean valid()
{
for (int i=0; i < cmbSampleName.Items.Count; i++)
{

            if (txtSampleName.Text == cmbSampleName.Items\[i\].ToString())
            {
                return true;
                break;
            }
            else
            {
                return false;
                
            }
        }

    }

i want to check weather the current text in textbox is present in combobox or not plz help

Lost User

Your code makes no sense, you're only checking the first item. Also, you're not returning anything if there are no items in the combobox, which is why you have a compile error. Maybe this is what you wanted? (warning: untested!)

public bool IsValid()
{
for (int i = 0; i < cmbSampleName.Items.Count; i++)
{
if (txtSampleName.Text == cmbSampleName.Items[i].ToString())
return true;
}
return false;
}

riced

I suggest stepping through it with the debugger and paying attention to what it does. If you cannot do that, then trace through the code manually setting i to 0 and considering both cases where if is true and where it is false. Then ask what happens if i is 1 - can it get there?. Here's a clue - it will not reach the break line.

Regards David R --------------------------------------------------------------- "Every program eventually becomes rococo, and then rubble." - Alan Perlis The only valid measurement of code quality: WTFs/minute.

Pete OHanlon

You may thing that you've got them all covered, but there's a big condition that you haven't checked. What happens if cmbSampleName.Items.Count is 0? The for loop won't execute, so a code path is causing you a problem. What you could do, is rewrite this by removing return false and place it outside the scope of the for loop (i.e. before the final }). This turns your method into:

public bool Valid()
{
for (int i=0; i < cmbSampleName.Items.Count; i++)
{
if (txtSampleName.Text == cmbSampleName.Items[i].ToString())
return true; // The break in the original sample is superflous here
// as it would never be reached.
}
return false;
}

Alternatively, you could use the Find method on cmbSampleName.Items to find out if the name is present or not (if it returns null, it's not present).

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Pete OHanlon

He won't be able to step through it as the code won't compile.

"WPF has many lovers. It's a veritable porn star!" - Josh Smith

As Braveheart once said, "You can take our freedom but you'll never take our Hobnobs!" - Martin Hughes.

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riced

That's why I suggested a manual trace - but do people get taught how to that these days? :)

Regards David R --------------------------------------------------------------- "Every program eventually becomes rococo, and then rubble." - Alan Perlis The only valid measurement of code quality: WTFs/minute.

OriginalGriff

Just to add the above:

Member 4081808 wrote:

return true; break;

Won't compile either: unreachable code - the "break" will never be executed as the method returns before it.

Did you know: That by counting the rings on a tree trunk, you can tell how many other trees it has slept with.

freakyit

lol thats wrong -> compile would succeed.. but bring up a warining as you described :D xyz :)

Lost User

This aint Java :)

freakyit

hmm i use #develop :) with C# xD

OriginalGriff

You mean you don't have "treat all warnings as errors" enabled? :omg: :laugh:

Did you know: That by counting the rings on a tree trunk, you can tell how many other trees it has slept with.

Luc Pattyn

:thumbsup:

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Please use < PRE > tags for code snippets, it preserves indentation, and improves readability.

Pete OHanlon

No. I develop in WPF where warnings are deferred until runtime.

"WPF has many lovers. It's a veritable porn star!" - Josh Smith

As Braveheart once said, "You can take our freedom but you'll never take our Hobnobs!" - Martin Hughes.

My blog | My articles | MoXAML PowerToys | Onyx

Luc Pattyn

Have you tried adding

? :)

Luc Pattyn [Forum Guidelines] [Why QA sucks] [My Articles] Nil Volentibus Arduum

Please use < PRE > tags for code snippets, it preserves indentation, and improves readability.

Anthony Mushrow

riced wrote:

but do people get taught how to that these days?

Well the course I did tried to. Of course they went to the other extreme and got us to design the application fully on paper and then set up test and run through manually and document the results, only once we had proved that the design worked as expected could we actually program it. I suppose it's good practice for simple programs (which was the case), to grasp the concept. But for most things it's usually quicker to design a more rough idea of what should be happening, code it and then debug the little problems. So in short, yes people do get taught that these days.

My current favourite quote is: Punch them in the face, see what happens!

-SK Genius

Pete OHanlon

SK Genius wrote:

it's usually quicker to design a more rough idea of what should be happening, code it and then debug the little problems

Isn't this the essence of Test Driven Development?

"WPF has many lovers. It's a veritable porn star!" - Josh Smith

As Braveheart once said, "You can take our freedom but you'll never take our Hobnobs!" - Martin Hughes.

My blog | My articles | MoXAML PowerToys | Onyx

Lost User

I have been thinking about how it would make sense to write code like this. After all, you wouldn't have written it like this if you had no reason to do so. I think I figured it out - did you think that return value; only sets the value that will be returned, instead of immediately* returning that value? It all makes sense then - as long as they are not equal, you would keep the return value on false; and when they are equal you'd set the return value to true and exit the method. The problem with that is, of course, that return doesn't "set the value that will be returned", it immediately* exits the method (and it also returns the specified value, of course) *: except in the presence of try/finally

yu jian

After the for loop you should return a value, because perhaps the for loop is not executed