read in a chunk of a text file up to a certain point into a string

Question

So let's say I have this text file:

(*********************************************

  Import-Export
  Version   := v24.00
  Owner     :=
  Exported  := Wed Oct 05 09:22:48 2016

  Note:  File encoded in UTF-8.  Only edit file in a program 
         which supports UTF-8 (like Notepad, not Wordpad).

**********************************************)
IE_VER := 2.15;

CONTROLLER controllerName (ProcessorType := "1756-L71",
                           Major := 24,
                           TimeSlice := 20,
                           ShareUnusedTimeSlice := 1,
                           RedundancyEnabled := 0,
                           KeepTestEditsOnSwitchOver := 0,
                           DataTablePadPercentage := 50,
                           SecurityCode := 0,
                           ChangesToDetect := 16#ffff_ffff_ffff_ffff,
                           SFCExecutionControl := "CurrentActive",
                           SFCRestartPosition := "MostRecent",
                           SFCLastScan := "DontScan",
                           SerialNumber := 16#0000_0000,
                           MatchProjectToController := No,
                           CanUseRPIFromProducer := No,
                           InhibitAutomaticFirmwareUpdate := 0,
                           PassThroughConfiguration := EnabledWithAppend,
                           DownloadProjectDocumentationAndExtendedProperties := Yes)
    MODULE Local (Parent := "Local",
                  ParentModPortId := 1,
                  CatalogNumber := "1756-L71",
                  Vendor := 1,
                  ProductType := 14,
                  ProductCode := 92,
                  Major := 24,
                  Minor := 11,
                  PortLabel := "RxBACKPLANE",
                  ChassisSize := 10,
                  Slot := 0,
                  Mode := 2#0000_0000_0000_0001,
                  CompatibleModule := 0,
                  KeyMask := 2#0000_0000_0001_1111)
    END_MODULE
...

And the "..." marks the continuation of the text file. If I want to just read in everything up to and including that "END_MODULE" there into a string how would I do that?

My idea is: read the whole file into a string, parse it by newlines and creating a do while loop of concatenating those array elements into a single string until one of them contains "END_MODULE" but that seems sort of backwards? Because I'm splitting the string into an array and then concatenating it back into a single string again. Is there a faster way than my idea?

Answer 1

If you want read line by line, here is sample code:

var builder = new StringBuilder();
using (var file = File.OpenRead("your file")) {
     using (var reader = new StreamReader(file)) {
        string line;                    
        while ((line = reader.ReadLine()) != "END_MODULE") {
            builder.AppendLine(line);
        }
     }                
 }
 string final = builder.ToString();

Benefit is that you don't read whole file into memory, only the part you need (which might help if you have really large file).