array.Contains("str", StringComparer.OrdinalIgnoreCase);
Or depending on the specific circumstance, you might prefer:
array.Contains("str", StringComparer.CurrentCultureIgnoreCase);
array.Contains("str", StringComparer.InvariantCultureIgnoreCase);
与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…