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A Modified C# Implementation of Tony Selke's TextFieldParser

By , 27 Feb 2005
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Application after parsing 1,500,000 fields.

Introduction

One day while browsing the Code Project, I found an excellent article by Tony Selke 'Wrapper Class for Parsing Fixed-Width or Delimited Text Files'. I decided that I would port the code to C# because that is my language of choice. While doing this, I also added a couple of features:

  1. I added the ability to put the schema for the text file in an XML file.
  2. I added the ability to parse the text file directly to a DataTable.

This is my first article submitted to the Code Project, so be gentle.

What can it do?

The library can import delimited or fixed width files while the developer decides what to do with each record by subscribing to the RecordFound event. The library can import delimited or fixed width files directly into a DataTable.

How does it work?

The developer sets up a schema either with code or in an XML schema file. This determines the data types that will be used in the DataTable. Based on the schema, the text values are parsed and converted to the respective data types and either put in a DataTable or simply passed to the calling object as an event.

Using the code

The first thing to do is, add a reference to the library. Then add the using statement at the top of your source file.

using WhaysSoftware.Utilities.FileParsers;

Create an instance of the TextFieldParser object.

TextFieldParser tfp = new TextFieldParser(filePath);

If you will be using an XML schema file, use the constructor that has the 'schemaFile' parameter.

TextFieldParser tfp = new TextFieldParser(filePath, schemaPath);

If using an XML schema file, the following is an example of how the XML schema file would look:

<TABLE Name="TEST" FileFormat="Delimited" ID="Table1">
    <FIELD Name="LineNumber" DataType="Int32" />
    <FIELD Name="Quoted String" DataType="String" Quoted="true" />
    <FIELD Name="Unquoted String" DataType="String" Quoted="false" />
    <FIELD Name="Double" DataType="Double" />
    <FIELD Name="Boolean" DataType="Boolean" />
    <FIELD Name="Decimal" DataType="Decimal" />
    <FIELD Name="DateTime" DataType="DateTime" />
    <FIELD Name="Int16" DataType="Int16" />
</TABLE>

I have included with the source code a complete description of the schema file attributes. Here is an example of the same thing, but done in code.

TextFieldCollection fields = new TextFieldCollection();
fields.Add(new TextField("Line Number", TypeCode.Int32));
fields.Add(new TextField("Quoted String", TypeCode.String, true));
fields.Add(new TextField("Unquoted String", TypeCode.String, false));
fields.Add(new TextField("Double", TypeCode.Double));
fields.Add(new TextField("Boolean", TypeCode.Boolean));
fields.Add(new TextField("Decimal", TypeCode.Decimal));
fields.Add(new TextField("DateTime", TypeCode.DateTime));
fields.Add(new TextField("Int16", TypeCode.Int16));
tfp.TextFields = fields;

Now you can either subscribe to the RecordFound event if you want to do something custom with the records...

tfp.RecordFound += new RecordFoundHandler(tfp_RecordFound);
tfp.ParseFile();
...
private void tfp_RecordFound(ref int CurrentLineNumber, 
                                         TextFieldCollection TextFields)
{
    //Do something with the TextFields parameter
}

or you can call ParseToDataTable to get the results in a DataTable.

DataTable dt = tfp.ParseToDataTable();

Note: Even when calling ParseToDataTable, the RecordFound event is still fired.

You can also subscribe to the RecordFailed event to get notification of when a record fails to parse. In the event handler, you can decide if you can continue or not.

tfp.RecordFailed += new RecordFailedHandler(tfp_RecordFailed);
...
private void tfp_RecordFailed(ref int CurrentLineNumber, 
        string LineText, string ErrorMessage, ref bool Continue)
{
    MessageBox.Show("Error: " + ErrorMessage + Environment.NewLine + 
                            "Line: " + LineText);
}

That's it. I look forward to comments, suggestions from you all.

History

  • 02/27/2005

    Initial release.

License

This article has no explicit license attached to it but may contain usage terms in the article text or the download files themselves. If in doubt please contact the author via the discussion board below.

A list of licenses authors might use can be found here

About the Author

WendellH
Web Developer
United States United States
I have BA in Computer Science from a small college in Indiana. I have been programming for about 7 years - mostly business applications.

Comments and Discussions

 
QuestionMissing columns in csv file Pinmembersentdata21-Nov-12 8:39 
GeneralMy vote of 3 Pinmemberoyangbingrui13-Jul-12 16:27 
GeneralMy vote of 5 PinmemberAnoop X29-Jun-11 1:23 
very good article. it helped me a lot.
QuestionStart Parameter PinmemberGavin O'Brien18-Mar-10 2:02 
GeneralTypeCode to Type Conversion PinmemberSNathani10-Feb-10 7:46 
GeneralNon alpha numeric characters Pinmembercbonsall19-Jun-07 1:23 
GeneralRe: Non alpha numeric characters Pinmembercbonsall19-Jun-07 1:38 
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