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

• Home
• Components
• Editors
• Introduction
• Tutorials
• FAQ
• Standard
• Licence
• Contact

Tutorial: Read a Basic CSV File with Delphi.Net

This tutorial demonstrates how to use the Xilytix TFieldedText component to read a CSV file and place the headings and records into a Delphi.NET StringGrid.

The contents of the CSV file to be imported are shown here

This text file has 2 headings and 4 records.  This tutorial will show how to read this file into a StringGrid on a Delphi.Net Form.  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: Get text file

Create a text file called "BasicReadExample.txt" and place the contents of the above CSV file into it.  Save this file to the folder where the compiled executable will run from (normally the project folder).  Alternatively download the text file from here (Right Click | Save Link/Target As) and save to the folder.

Step 3: 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.

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

Step 4: 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 5: Reference the FieldedText Assembly

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

Step 6: Place controls on Form

Add the following items to a form in the project:

• A StringGrid with Name = "StringGrid1"
• A Button

Step 7: Add units to uses clauses

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

Step 8: Button Click event

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

var
  FieldedText: TFieldedText;
  LineIdx: Integer;
  FieldIdx: Integer;
  Reader: IDataReader;

  PetNameOrd: Integer;
  AgeOrd: Integer;
  ColorOrd: Integer;
  DateReceivedOrd: Integer;
  PriceOrd: Integer;
  NeedsWalkingOrd: Integer;
  TypeOrd: Integer;
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');

  // Parse the file once to work out get headers and calculate number or records
  FieldedText.Parse('BasicReadExample.txt', True);

  // Set up grid
  StringGrid1.ColCount := FieldedText.FieldCount;
  StringGrid1.RowCount := FieldedText.HeadingLineCount + FieldedText.RecordCount;
  StringGrid1.FixedRows := FieldedText.HeadingLineCount;

  // Write Headers to Grid
  for LineIdx := 0 to FieldedText.HeadingLineCount - 1 do
  begin
    for FieldIdx := 0 to FieldedText.FieldCount - 1 do
    begin
      StringGrid1.Cells[FieldIdx, LineIdx] := FieldedText.Fields[FieldIdx].Headings[LineIdx];
    end;
  end;

  // Use a standard IDataReader to get information for records
  Reader := FieldedText.ExecuteReader('BasicReadExample.txt');

  // Use GetOrdinal to reference fields
  PetNameOrd := Reader.GetOrdinal('PetName');
  AgeOrd := Reader.GetOrdinal('Age');
  ColorOrd := Reader.GetOrdinal('Color');
  DateReceivedOrd := Reader.GetOrdinal('DateReceived');
  PriceOrd := Reader.GetOrdinal('Price');
  NeedsWalkingOrd := Reader.GetOrdinal('NeedsWalking');
  TypeOrd := Reader.GetOrdinal('Type');

  LineIdx := FieldedText.HeadingLineCount;

  // Read records and write values to grid
  while Reader.Read do
  begin
    StringGrid1.Cells[0, LineIdx] := Reader.GetString(PetNameOrd);
    if Reader.IsDBNull(AgeOrd) then
      StringGrid1.Cells[1, LineIdx] := '<Null>'
    else
      StringGrid1.Cells[1, LineIdx] := Reader.GetDouble(AgeOrd).ToString;
    StringGrid1.Cells[2, LineIdx] := Reader.GetString(ColorOrd);
    StringGrid1.Cells[3, LineIdx] := Reader.GetDateTime(DateReceivedOrd).ToString;
    StringGrid1.Cells[4, LineIdx] := Reader.GetDecimal(PriceOrd).ToString;
    StringGrid1.Cells[5, LineIdx] := Reader.GetBoolean(NeedsWalkingOrd).ToString;
    StringGrid1.Cells[6, LineIdx] := Reader.GetString(TypeOrd);

    Inc(LineIdx);
  end;
end;

Step 9: Compile and Run

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

1. Create a TFieldedText object
2. Load the Meta
3. Parse the file once to get headings
4. Set up columns and rows in StringGrid
5. Read the Headings into StringGrid
6. Parse the file again with an IDataReader to get Records
7. Place each record into a row in the StringGrid