Events Architecture

Some time you need to ignore certain lines in files or you need to change a value after the record is filled, etc.

To solve these problems I´ve add a event architecture in the FileHelperEngine (in the future in all the others)

The events are 4 (2 for read and 2 for write ops):

• BeforeReadRecord
• AfterReadRecord
• BeforeWriteRecord
• AfterWriteRecord

The names said all right ?

The Example

Supose that you need to parse a txt report from a legacy system with these format

----------------------------------------------------- XXX Enterprise ----------------------------------------------------- 10249 TOMSP 05071996 11.61 10250 HANAR 08071996 65.83 10251 VICTE 08071996 41.34 ............... Page 1 ----------------------------------------------------- XXX Enterprise ----------------------------------------------------- 10269 TOMSP 05071996 11.61 10230 HANAR 08071996 65.83 10151 VICTE 08071996 41.34 ............... Page 2 And so on !!

You must declare a Record Mapping Class for the main record:

[FixedLengthRecord(FixedMode.AllowVariableLength)] [FixedLengthRecord] public class OrdersFixed { [FieldFixedLength(7)] public int OrderID; [FieldFixedLength(8)] public string CustomerID; [FieldFixedLength(8)] public DateTime OrderDate; [FieldFixedLength(11)] public decimal Freight; }

So now is the time where we instanciate the engine and hook to the events.

FileHelperEngine engine = new FileHelperEngine(typeof(Orders)); engine.BeforeReadRecord += new BeforeReadRecordHandler(BeforeEvent); Orders[] res = engine.ReadFile("report.txt") as Orders[];

So in the event method we ignore the lines with spaces and -

private void BeforeEvent(EngineBase engine, BeforeReadRecordEventArgs e) { if (e.RecordLine.StartsWith(" ") || e.RecordLine.StartsWith("-")) e.SkipThisRecord = true; }

Note: if you change the RecordLine the engine use the changed value This can be useful in some cases but you must be carefull

See also

Must Read - Quick Start Guide - Attributes List - F.A.Q. - Examples of Use - Contacts & Credits - Donations

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