This exception indicates that the .NET runtime has exhausted all available memory and usually means the CLR is in deep danger of dying altogether.

public class OutOfMemoryException : SystemException {
// Public Constructors
   public OutOfMemoryException( );
   public OutOfMemoryException(string message);
   public OutOfMemoryException(string message, Exception innerException);
// Protected Constructors
   protected OutOfMemoryException(System.Runtime.Serialization.SerializationInfo info,
        System.Runtime.Serialization.StreamingContext context);
}

Hierarchy

Object Exception(System.Runtime.Serialization.ISerializable) SystemException OutOfMemoryException