string upstr = Regex.Replace(str, @"(\w{4}(?=[^$]))", "$1-");
注意引用：using System.Text.RegularExpressions;
比如：74B87337454200D4D33F80C4663DC5E5运用它后就变成：74B8-7337-4542-00D4-D33F-80C4-663D-C5E5
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更新时间：2022-09-16 16:23:20
string upstr = Regex.Replace(str, @"(\w{4}(?=[^$]))", "$1-");
注意引用：using System.Text.RegularExpressions;
比如：74B87337454200D4D33F80C4663DC5E5运用它后就变成：74B8-7337-4542-00D4-D33F-80C4-663D-C5E5