如何从与正则表达式类似的复杂格式生成字符串？
我们知道String.format（）可以接受这种样式的格式：
%[argument_index$][flags][width][.precision]conversion
select %1 from %2 where %3 and give %1->'*' %2->'users' %3->'age>20'
select * from users where age>20
select %1{, } from (%2(as %3)){,} (where %4 (and %5))?
when: %1->'*', %2->'users' %3->null, %3->'age>20'
select * from users where age>20
when: %1->Stirng{'name','age'} , %2->'users' %3->'u', %4->'age>20', %5->null
select name, age from users as u where age>20
when: %1->Stirng{'name','age'} , %2->'users' %3->'u', %4->null, %5->null
select name, age from users as u
when: %1->Stirng{'name','age'} , %2->String{'users','order'} %3->{'u','o'}, %4->'age>20', %5->'u.id=o.userid'
select name, age from users as u,orders as o where age>20 and u.id=o.userid
没有找到相关结果
已邀请:
1 个回复
缮淳彼誊
class SqlFormatter:IFormatProvider, ICustomFormatter { public object GetFormat(Type formatType) { return this; } public string Format(string format, object arg, IFormatProvider formatProvider) { StringBuilder concat = new StringBuilder(); string[] formatParts = format.Split(':'); switch (formatParts[0]) { case "sqlfield": string sep = ""; if (formatParts.Length>1) { sep = formatParts[1]; } string[] fields = (string[]) arg; concat.Append(fields[0]); for (int fieldIndex = 1; fieldIndex < fields.Length; fieldIndex++) { concat.Append(sep); concat.Append(fields[fieldIndex]); } break; case "sqltables": concat.Append(arg.ToString()); break; default: break; } return concat.ToString(); } }String sql = String.Format( new SqlFormatter() , "select {0:sqlfield:,} from {1:sqltables} " , new string[]{"name","lname"} , "person" );