QR Code容错级别有4种，可以让前端下拉列表选择H, L, M或Q
当传入服务端，处理QR Code时，Zxing模块接收的却不是字符串"H","L","M","Q"
所以，Insus.NET写一个静态扩展方法来处理这个参数：
public static ErrorCorrectionLevel ToErrorCorrectionLevel(this string value) { var ecl = ErrorCorrectionLevel.H; switch (value) { case "H": ecl = ErrorCorrectionLevel.H; break; case "L": ecl = ErrorCorrectionLevel.L; break; case "M": ecl = ErrorCorrectionLevel.M; break; case "Q": ecl = ErrorCorrectionLevel.Q; break; } return ecl; }
原文：https://www.cnblogs.com/insus/p/13539064.html
