Return value of a function

[pankajit09]

I get the below warning :

Warning	1	Function 'exportToCSV' doesn't return a value on all code paths. A null reference exception could occur at run time when the result is used.	C:\Documents and Settings\cxvngh\My Documents\Visual Studio 2008\Projects\OutCre\OutCre\Module1.vb	193	5	OutCre

To solve it I put a return statement "Return 1" in the code.

Is it the right way ?

[PRR]

Your function does not return on all code paths

public static int Call()
        {
            int i = 90;

            if (i > 90)
            {
                return i;
            }
// Here we need a default return... 
        }


public static int Call()
        {
            int i = 90;

            if (i > 90)
            {
                return i;
            }

            else
            {
                return -1;
            }
        }

[Frinavale]

Just in case you don't understand what DeepBlue has said I'll restate it.

If you are creating a method that does not return anything then you should define it as a Sub.

For example, the following method definition is of a method that does not return a value:

Private Sub ExportToCSV()
  'Your code goes here
End Sub

If your method returns something (say the path to the file you created) then you would define it as a Function.

For example, the following method returns a String:

Private Function ExportToCSV() As String
  Dim path As String = "C:\MyFolder\MyCVSFileName.cvs"

  'Your code goes here
  
   return path
End Function

You are getting that message because your Function is not returning a value.
If you have an "if" statement in your function that returns a value, you must also have a "default" return value for the function. In other words your function must always return something if it's a function.

For example, the following will cause an error because there is no default return value:

Private Function ExportToCSV() As String
  Dim path As String = "C:\MyFolder\MyCVSFileName.cvs"
  If someBoolean = True Then
    return path
  End If

  'Your code goes here
  
End Function

It is advisable to always have 1 return statement in a method just to keep things less confusing and to avoid this type of error.


-Frinny