C#

Quote:

Without them, you can easily introduce bugs where resources don't get cleaned up.

Quote:

A using block should be used where appropriate

Quote:

I'm going to concerned with just two things. Any exceptions thrown by the Command and the data returned.

SqlCommand cmd = new SqlCommand(sql, con);
try
   {
   ...
   }
finally
   {
   if (cmd != null) cmd.Dispose();
   }
cmd.ExecuteNonQuery();  // Perfectly valid, cmd is in scope.

using (SqlCommand cmd = new SqlCommand(sql, con))
   {
   ...
   }
cmd.ExecuteNonQuery();  // Compiler error, cmd is not in scope.

Quote:

And ... it makes the scope of the variable very, very obvious which a try...finally block doesn't

SqlCommand cmd = null;

Quote:

using is cleaner, clearer, and easier to use.

Quote:

Your second example would be caught in the IDE, before you even tried to compile.

Quote:

you do realise that VS does a partial compilation while you type I assume

MSBassSinger wrote:

But easier does not always lead to better, more reliable, or less buggy. For the small amount of extra effort to use try-catch-finally, it seems to me to be worth the effort. I've run into objects created via the using statement that left me with odd behavior that could not be stepped through in a using statement. But once I did away with the using statement, and used try-catch-finally, I found the problem and corrected it within minutes. So to avoid these unnecessary, but rare issues, I don't take shortcuts like the using statement. I realize the responsibility is 100% on me to cleanup the objects I create, and I am OK with that.

BillWoodruff wrote:

or, even the now deprecated ArrayList

Image img;

public tab()
{
    InitializeComponent();
    
    if (!DesignMode && File.Exists("google.png"))
    {
        img = new Bitmap("google.png");
    }
}

private void tab_Paint(object sender, PaintEventArgs e)
{
    if (img != null)
    {
        e.Graphics.DrawImage(img, rect);
    }
}

private string ResolveImagePath()
{
    string path = "google.png";
    if (DesignMode)
    {
        var typeResolver = (ITypeResolutionService)GetService(typeof(ITypeResolutionService));
        if (typeResolver != null)
        {
            AssemblyName name = System.Reflection.Assembly.GetExecutingAssembly().GetName();
            string basePath = typeResolver.GetPathOfAssembly(name);
            path = Path.Combine(basePath, path);
        }
    }
    
    return path;
}

public tab()
{
    InitializeComponent();
    
    string imagePath = ResolveImagePath();
    if (File.Exists(imagePath))
    {
        img = new Bitmap(imagePath);
    }
}

public tab()
{
    InitializeComponent();
}


Image img = new Bitmap(@"google.png");
Rectangle rect = new Rectangle(5, 5, 22, 22);

private void tab_Paint(object sender, PaintEventArgs e)
{
    e.Graphics.DrawImage(img, rect);
}

public partial class tab : UserControl
{
    public tab()
    {
        InitializeComponent();
        if (!DesignMode && File.Exists("google.png"))
        {
            img = new Bitmap("google.png");
        }
    }


    Image img;
    Rectangle rect = new Rectangle(5, 5, 22, 22);

    private void tab_Paint(object sender, PaintEventArgs e)
    {
        e.Graphics.DrawImage(img, rect);
    }

_Q12_ wrote:

another Error appear

private void tab_Paint(object sender, PaintEventArgs e)
{
    if (img != null)
    {
        e.Graphics.DrawImage(img, rect);
    }
}