截取字符串

            string str = "Q://ABC/CBA/DBD";
            string path = @"DllDownLoad\1\da.txt";
            string u = @"DllDownLoad\";
            string strArray = str.Substring(0, str.IndexOf("DBD"));//输出strArray = Q://ABC/CBA/
            
            string p = path.Replace(u, string.Empty);//输出p = 1\da.txt

 

userId = context.substring(context.indexOf("UserId")+8,context.indexOf(",",context.indexOf("UserId")+8));//

 

str = "DFJKLSDJFKLDJSKL1FJ3SDKLJLDFJSL1SD"
int start = str.IndexOf("1F");//找到“1F”
int end = str.IndexOf("3");//找到以“3”
substr = str.SubString(start,end - start);//找到“1F”-“3”之间的字符串，可以通过+1或-1增加或者减少字符串

str.Replace(str.Substring(start, end - start + 1), string.Empty);//将指定的字符串用空代替