Safely make sure that a List is not NULL or Empty in C#.
The following Extension Method and corresponding sample code works well whether the List object has been initialized or not. The "!=null" ensures that the object is initialized and the ".Any()" makes sure that there are items in the List.
List<string> recipients = new List<string>();
/*
recipients.Add("joe@here.com");
recipients.Add("nobdy@here.com");
*/
//recipients = null;
if (recipients.IsNullOrEmpty<string>())
{
MessageBox.Show("Empty List");
}
else
{
MessageBox.Show("We have a good Recipient List");
}
/// <summary>
/// Extension Metion to verify that a Generic List is not NULL or Empty
/// </summary>
/// <typeparam name="T">List Type</typeparam>
/// <param name="source"><see cref="List"/> Source</param>
/// <returns><see cref="bool"/> (true/false)</returns>
public static bool IsNullOrEmpty<T>(this List<T> source)
{
if (source != null && source.Any())
{
return false;
}
else
{
return true;
}
}