Write a Basic CSV File

Tutorial: Write a Basic CSV File with Delphi.Net

This tutorial demonstrates how to use the Xilytix TFieldedText component to write headings and records to a CSV file.

The 2 headings and 4 records to be written to the file, are shown in the table below:

Pet Name	Age	Color	Date Received	Price	Needs Walking	Type
	(Years)			(Dollars)
Rover	4.5	Brown	12 Feb 2004	80	True	Dog
Charlie		Gold	5 Apr 2007	12.3	False	Fish
Molly	2	Black	12 Dec 2006	25	False	Cat
Gilly		White	10 Apr 2007	10	False	Guinea Pig

By using TFieldedText to write the CSV file, you do not have to worry about formatting. TFieldedText will ensure that the data in the CSV file is laid out as specified by the Meta.

The full source code for this tutorial lesson can be downloaded from the component's home page

Step 1: Select a folder

Create or select an empty folder for the program we are going to develop.

Step 2: Create Fielded Text Meta file

The Meta file specifies the structure of the text file. In this step we will create a Meta file called "BasicExample.ftm" for the text file. There are 2 ways of doing this.

The easy way is to simply download the Meta file from here (Right Click | Save Link/Target As) and place in the folder where the compiled executable will run from (normally in the bin\Debug folder beneath the project folder).

Alternatively, you can create it with a Fielded Text Editor. This will provide a better understanding of what a Meta file actually is. Follow the steps here to create the "BasicExample.ftm" and then save it into the folder where the compiled executable will run from.

The contents of the Fielded Text Meta File should be similar to the text shown below

<?xml version="1.0" encoding="utf-8"?>
<FieldedText HeadingLineCount="2" HeadingWritePrefixSpace="True">
  <Field Name="PetName" ValueQuotedType="Always" HeadingWritePrefixSpace="False" Headings="Pet Name" />
  <Field DataType="Float" Name="Age" ValueWritePrefixSpace="True" Headings="Age, " />
  <Field Name="Color" ValueWritePrefixSpace="True" Headings="Color, (Years)" />
  <Field DataType="DateTime" Name="DateReceived" ValueWritePrefixSpace="True" Headings="Date Received, " Format="d MMM yyyy" />
  <Field DataType="Decimal" Name="Price" ValueWritePrefixSpace="True" Headings="Price, (Dollars)" />
  <Field DataType="Boolean" Name="NeedsWalking" ValueWritePrefixSpace="True" Headings="Needs Walking, " />
  <Field Name="Type" ValueQuotedType="Always" ValueWritePrefixSpace="True" Headings="Type" />
</FieldedText>

Step 3: Create a Delphi.Net VCL Forms Application project

Create a Delphi.Net VCL Forms Application project in the folder using one of: BDS 2005, BDS 2006 or Turbo Delphi.Net

Step 4: Reference the FieldedText Assembly

Add a reference to the Xilytix.FieldedText.dll assembly. The assembly can be downloaded from here.

Step 5: Place controls on Form

Add the following items to a form in the project:

A TMemo with Name = "Memo1"
A Button

Step 6: Add units to uses clauses

Make sure that the following units are are included in the interface and implementation uses clauses.

interface
uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms, Dialogs,
  Borland.Vcl.StdCtrls,
  System.ComponentModel;

...

implementation
uses
  System.Text,
  System.IO,
  Xilytix.FieldedText.Main;

Step 7: Button Click event

Add the following code to the Click event of the button:

var
  FieldedText: TFieldedText;

  PetNameIdx: Integer;
  AgeIdx: Integer;
  ColorIdx: Integer;
  DateReceivedIdx: Integer;
  PriceIdx: Integer;
  NeedsWalkingIdx: Integer;
  TypeIdx: Integer;

  Bldr: StringBuilder;
  Writer: StringWriter;
begin
  FieldedText := TFieldedText.Create;

  // Load the Meta which describes the text file
  // A Fielded Text Editor is used to create the Meta File.
  FieldedText.LoadMeta('BasicExample.ftm');

  // Find Field Indices
  PetNameIdx := FieldedText.IndexOfField('PetName');
  AgeIdx := FieldedText.IndexOfField('Age');
  ColorIdx := FieldedText.IndexOfField('Color');
  DateReceivedIdx := FieldedText.IndexOfField('DateReceived');
  PriceIdx := FieldedText.IndexOfField('Price');
  NeedsWalkingIdx := FieldedText.IndexOfField('NeedsWalking');
  TypeIdx := FieldedText.IndexOfField('Type');

  // Set up Headers
  FieldedText.Fields[PetNameIdx].Headings[0] := 'Pet Name';
  FieldedText.Fields[AgeIdx].Headings[0] := 'Age';
  FieldedText.Fields[AgeIdx].Headings[1] := '(Years)';
  FieldedText.Fields[ColorIdx].Headings[0] := 'Color';
  FieldedText.Fields[DateReceivedIdx].Headings[0] := 'Date Received';
  FieldedText.Fields[PriceIdx].Headings[0] := 'Price';
  FieldedText.Fields[PriceIdx].Headings[1] := '(Dollars)';
  FieldedText.Fields[NeedsWalkingIdx].Headings[0] := 'Needs Walking';
  FieldedText.Fields[TypeIdx].Headings[0] := 'Type';

  // Create a writer
  Bldr := StringBuilder.Create;
  Writer := StringWriter.Create(Bldr);


  // Start writing.  Header will automatically be written
  FieldedText.BeginWrite(Writer);

  // Set up values for first record
  FieldedText.Fields[PetNameIdx].AsString := 'Rover';
  FieldedText.Fields[AgeIdx].AsDouble := 4.5;
  FieldedText.Fields[ColorIdx].AsString := 'Brown';
  FieldedText.Fields[DateReceivedIdx].AsDateTime := DateTime.Create(2004, 2, 12);
  FieldedText.Fields[PriceIdx].AsDecimal := 80.0;
  FieldedText.Fields[NeedsWalkingIdx].AsBoolean := True;
  FieldedText.Fields[TypeIdx].AsString := 'Dog';

  // Write First Record
  FieldedText.WriteRecord;

  // Repeat for next 3 records
  FieldedText.Fields[PetNameIdx].AsString := 'Charlie';
  FieldedText.Fields[AgeIdx].Null := True;
  FieldedText.Fields[ColorIdx].AsString := 'Gold';
  FieldedText.Fields[DateReceivedIdx].AsDateTime := DateTime.Create(2007, 4, 5);
  FieldedText.Fields[PriceIdx].AsDecimal := 12.3;
  FieldedText.Fields[NeedsWalkingIdx].AsBoolean := False;
  FieldedText.Fields[TypeIdx].AsString := 'Fish';
  FieldedText.WriteRecord;

  FieldedText.Fields[PetNameIdx].AsString := 'Molly';
  FieldedText.Fields[AgeIdx].AsDouble := 2.0;
  FieldedText.Fields[ColorIdx].AsString := 'Black';
  FieldedText.Fields[DateReceivedIdx].AsDateTime := DateTime.Create(2006, 12, 12);
  FieldedText.Fields[PriceIdx].AsDecimal := 25;
  FieldedText.Fields[NeedsWalkingIdx].AsBoolean := False;
  FieldedText.Fields[TypeIdx].AsString := 'Cat';
  FieldedText.WriteRecord;

  FieldedText.Fields[PetNameIdx].AsString := 'Gilly';
  FieldedText.Fields[AgeIdx].Null := True;
  FieldedText.Fields[ColorIdx].AsString := 'White';
  FieldedText.Fields[DateReceivedIdx].AsDateTime := DateTime.Create(2007, 4, 10);
  FieldedText.Fields[PriceIdx].AsDecimal := 10.0;
  FieldedText.Fields[NeedsWalkingIdx].AsBoolean := False;
  FieldedText.Fields[TypeIdx].AsString := 'Guinea Pig';
  FieldedText.WriteRecord;

  // Finish Writing
  FieldedText.EndWrite;
  Writer.Close;

  // Place in Memo
  Memo1.Text := Bldr.ToString;
end;

Step 8: Compile and Run

Compile and run the program. When the button is clicked, the program will do the following:

Create a TFieldedText object
Load the Meta
Find the indices of the fields
Set up the headings in the FieldedText object
Create a StringWriter to write text to a StringBuilder
Use FieldedText.BeginWrite to initiate writing of text. This call will automatically write the headings.
Write the records
Use FieldedText.EndWrite to finish the writing process
Place generated string in the Memo control

Fielded Text: Tutorials: Write a Basic CSV File (Delphi.Net)