combining methods

Question

I am a beginner so please forgive my ignorance.

In my app I have a lot of copy and paste code that is exactly the same and performs exactly the same function (button click events and the like). These redundant code live in the code-behind of many of my pages. So I decided to reduce the code duplication and to move these methods into a class file and only make a call to them from the code-behind pages.

Here is an example of a button click event in my code behind calling the methods from a class file:

#region DELETE selected users - button

protected void btnDeleteSelected_Click(object sender, EventArgs e)
{
    try
    {
        UserGvUtil.DeleteSelectedUsersAndProfiles(GridView1, Msg);
    }
    catch (Exception ex)
    {
        UserGvUtil.ExceptionErrorMessage(Msg, ex);
    }
    finally
    {
        UserGvUtil.RefreshGridView(GridView1);
    }
}

#endregion

My question is, can I combine this try/catch block into yet another method and move it to the same class file? So, the only thing I have in the click event is a single line of code.

Does it make sense to do this? Not sure why, but I would like to have my code behind files as clean and simple as possible so I can make all the edits in a single place.

Sorry if I make no sense. I'm just learning about classes and methods and it floods my head with lots of ideas.

Answer 1

You can move the stuff inside the try block into an anonymous delegate that you pass to a shared method that has a try/catch. You really don't need to put the refresh into the finally, though. In fact, I would think you would only want to run it if the try block succeeds.

Answer 2

I have a lot of copy and paste code that is exactly the same ... (button click events and the like)

Just move all of that code that's duplicated behind multiple click handlers into a method in a separate class and pass whatever's needed (in this case the GridView and whatever that MSG object is) as parameters. If its saving significant duplication then it would make sense to do so. DRY (Don't Repeat Yourself) is a valid principle.

Answer 3

You could maybe start by creating a class in a new file and using it in your pages. I think it would be a good start, so that later on you can create more complicated classes and re use all your code.

public class Additionner //declaring the class
{
   public int calcul(int a, int b) //declaring a method that add 2 numbers
   {
     return a + b; //returning result
   }
}

Then use your class inside one of your page

Additionner MyCoolObject = new Additionner(); //create the Additionner
int Result = MyCoolObject.calcul(1,2); //call the "calcul" method

Answer 4

You can wire the event handlers manually.

btnDeleteSelected1.Click += Events.BtnDeleteSelected_Click;
btnDeleteSelected2.Click += Events.BtnDeleteSelected_Click;
...
btnDeleteSelected3.Click += Events.BtnDeleteSelected_Click;

public static class Events
{
  public static BtnDeleteSelected_Click(object sender, EventArgs e)
  {
     ...
  }
}

Edit (for downvoters: ???) The code will give you a one liner and you won't have to worry about writing custom events when they are all the same.

Also, if the utility methods have the same signature you could have a generic method:

public void ExecuteGvMethod(Action<GridView, string> gvMethod, GridView gv, string msg)
{
    try
    {
        gvMethod(gv, msg);
    }
    catch (Exception ex)
    {
        UserGvUtil.ExceptionErrorMessage(msg, ex);
    }
    finally
    {
        UserGvUtil.RefreshGridView(GridView1);
    }
}

And in code:

public static class Events
{
  public static BtnDeleteSelected_Click(object sender, EventArgs e)
  {
    ExecuteGvMethod(UserGvUtil.DeleteSelectedUsersAndProfiles, (GridView)sender, "hi of whatever");
  }
}

Answer 5

I'm risking a downvote, but here are my 2 cents:

Instead of using a try/catch, use a method that returns a status code. For instance (just an idea, instead of using enum you can use a more complex class):

public enum StatusCode
{
    Success = 1,
    Error =2
}

public class UserGvUtil
{
    public StatusCode getStatusAfterDelete(GridView GridView1, string Msg) 
    {
        try
        {
            DeleteSelectedUsersAndProfiles(GridView1, Msg);
            Return StatusCode.Success;
        }
        catch (Exception ex)
        {
            UserGvUtil.ExceptionErrorMessage(Msg, ex);
            Return StatusCode.Error;
        }
    }

//your other methods here
}

Then in code behind:

protected void btnDeleteSelected_Click(object sender, EventArgs e)
{
    StatusCode sc = UserGvUtil.getStatusAfterDelete(GridView1, Msg);

    //then do something with the status code if you have to:
    if (sc==StatusCode.Error) throw new Exception("Error deleting users and profiles");
    else UserGvUtil.RefreshGridView(GridView1);

}

That way you can change your try/catch later if you think it affects performance etc...
Hope it helps.