C# Preconditions

Preconditions.cs

public class Preconditions
{
    /// <summary>
    /// Ensures that an object reference passed as a parameter to the calling method is not null.
    /// </summary>
    /// <param name="reference">an object reference</param>
    /// <param name="errorMessage">the exception message to use if the check fails</param>
    /// <returns>the non-null reference that was validated</returns>
    /// <exception cref="NullReferenceException">if reference is null</exception>
    public static T CheckNotNull<T>(T reference, string errorMessage)
    {
        if (reference == null)
        {
            throw new NullReferenceException(errorMessage);
        }

        return reference;
    }
}