Deleting an exiting file

A Repasky

My lead programmer wants me to use the code below to write out the records on a file.








The problem is that if the file is already existing them it does not delete the old file and create a new file and only appends.
I was doing it another way and he did not like it because it was like VB.
Is there way to check for an existing file and delete it with this "using" statement.  I know this seem dumb, but that is what he wants.

 






      public static void Printweekly(string Output)
      {         
         using (StreamWriter weekly = new StreamWriter(Program.location + "\\" + Program.name + Program.weeklyEndDate + ".csv", true))
         {
            weekly.WriteLine("{0}", Output);

         }     
      }


 

Can anyone help?  Thanks ahead of time.

arep

8 Replies

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Zoran Horvat15y ago
Accepted answer
One additional note - if loop from which Printweekly is invoked executes immediately, i.e. it doesn't wait for something in each iteration, then it is more efficient to place the loop inside the using block, rather than the opposite. In this way, file is opened and closed for each row added, which is quite inefficient.

Zoran
Vulpes15y ago
Yes, I remember the 'using' statement being added quite late in the C# version 1.0 Beta cycle.

They didn't want to introduce a new keyword at that stage as a lot of code had already been written, so they overloaded the 'using' keyword which, of course, is also used to import namespaces.

I've never really liked the 'using' statement either (I'd have liked it better if they'd used a different keyword) but it's difficult to think of anything better and, after 10 years, it'll never be changed now.

C++/CLI has both a destructor (~MyClass) and a finalizer (!MyClass) - the former calls IDisposable.Dispose() and the latter is equivalent to C#'s destructor - but this is even more confusing IMO.
Sam Hobbs15y ago
I also do not like the "using" statement but it is Microsoft's recommended way to do things. So here is an explanation that might help you understand why it is the way it is.

The C# language and .Net are designed to use garbage collection. The initial design of C# did not have the IDispose interface; it was added during beta testing of C#. So initially there was no need to ensure that an object is disposed of. The "using" statement was created to ensure that IDispose is called and to ensure that any other relevant cleanup is done. The "using" statement seems inelegant to me and it is a kluge; I agree that it is part of C# that is not designed as well as it could be. There are many other things about C# that are designed well.
A Repasky15y ago
Zoran,

Thanks, it does work the way I want it now. I already knew that it will open and close it everytime in the loop. I was opening it with a FileStream as below, but the Lead Programmer did not want it. He wants me to use the new feature of .NET the using statement. In fact, he was over my shoulder telling me what to do. So I thank you for your help. In testing the programs, it was getting irratible to have to go in and delete the file or files everytime. I am going to end up with a lot of programs that do the same thing. So thanks for the help.

arep
```
    FileStream output = new FileStream(MedStatFile, FileMode.Create, FileAccess.Write);
    MedStatWriter = new StreamWriter(output);
```
A Repasky15y ago
That sounds good and I well try it. I have to leave, but I will try it as soon as I can.

Thanks,
arep

Zoran Horvat15y ago

In that case using block has no information whether it should append or overwrite the file. So that information should be given from the outside as function's argument. For example, code might be looking like this:

public static void Printweekly(string Output, bool append)

      {         
         using (StreamWriter weekly = new StreamWriter(Program.location + "\\" + Program.name + Program.weeklyEndDate + ".csv", append))
         {
            weekly.WriteLine("{0}", Output);

         }     
      }

In this way, first call to the method would be made with append=false, and all further calls would be made with append=true.

Zoran

A Repasky15y ago
I tried that using False. The problem is this is in a loop and it ends up with only one record. Each time it is called it deletes the file and writes a record, so only the last record is in the file.

arep
Zoran Horvat15y ago
The second parameter value in StreamWriter constructor should be false:
StreamWriter weekly = new StreamWriter(Program.location + "\\" + Program.name + Program.weeklyEndDate + ".csv", false)
That will force StreamWriter to overwrite the file if it exists, or otherwise to create new file if one does not exist.
Zoran