TextBox Validation in Delphi
Delphi validation program
Follow the instructions / procedures below:
1. Open your Delphi IDE
2. Create a Form with 2 TLabels, 2 TEdit and 1 TButton, Just like this:
3. Copy and paste the sourcecodes below:

unit Unit1;
interface
uses
Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls;
type
TForm1 = class(TForm)
Edit1: TEdit;
Label1: TLabel;
Edit2: TEdit;