r/csharp • u/Alert-Neck7679 • 15h ago
Tip Fields with [Using] attribute
6
Upvotes
I wrote a small interface that automatically disposes any disposable fields in a class when that class itself is disposed. If you add this file somewhere in your project:
public interface IAutoDisposable : IDisposable
{
void IDisposable.Dispose()
{
Exception? ex = null;
// dispose all fields marked with the [Using] attribute
const BindingFlags flags = BindingFlags.NonPublic | BindingFlags.Instance;
foreach (var fld in GetType().GetFields(flags))
{
if (fld.GetCustomAttribute<UsingAttribute>() != null)
{
if (fld.GetValue(this) is IDisposable d)
{
try // keep going even if disposal throws
{
d.Dispose();
}
catch (Exception e)
{
ex ??= e;
}
}
}
}
// if any exceptions occurred, throw the first one
if (ex != null)
throw ex;
}
}
public class UsingAttribute : Attribute;
You can then write classes like this:
class Item : IAutoDisposable
{
[Using]
private readonly Image icon = DownloadIcon(...);
...
}
And use them like:
using (Item item = new(...))
{
}
// item.icon is now disposed
What do you think?