I recently wrote an extension method named IsNullOrEmpty() for IEnumerable<> types. Dave had already written one all IEnumerable types:
public static bool IsNullOrEmpty(this IEnumerable source)
{
if (source != null)
{
IEnumerator enumerator = source.GetEnumerator();
return !enumerator.MoveNext();
}
return true;
}
This method has been useful countless times, but Bek realized this could leave open database connections, or cause other problems related to not calling Dispose. I added the overload:
public static bool IsNullOrEmpty<T>(this IEnumerable<T> source)
{
if (source != null)
{
using (IEnumerator<T> enumerator = source.GetEnumerator())
{
return !enumerator.MoveNext();
}
}
return true;
}
A question was raised about whether the generated finally block would be executed if the method returned inside the try block. I couldn’t remember the answer, but a quick test with LINQPad gave us our answer:
try
{
return;
}
finally
{
“Hello world”.Dump();
}
“Hello world” was displayed in the output box. If the finally block weren’t executed before the method returned, we’d have to store the return value in a temporary variable and place the return statement after the end of the using/finally block. It’s one of the small tidbits that are nice to know.
