unit Unit1;
interface
uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls, Registry, wininet;

type
  TfrmMain = class(TForm)
    chkEnabled: TCheckBox;
    edtProxy: TEdit;
    btnRead: TButton;
    btnWrite: TButton;
    procedure btnReadClick(Sender: TObject);
    procedure btnWriteClick(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  frmMain: TfrmMain;
implementation
{$R *.dfm}

procedure TfrmMain.btnReadClick(Sender: TObject);
var
    Registry: TRegistry;
begin
    Registry := TRegistry.Create(KEY_READ);
    try
        Registry.RootKey:= HKEY_CURRENT_USER;
        Registry.OpenKey('\Software\Microsoft\Windows\CurrentVersion\Internet Settings', False);
        edtProxy.Text:= Registry.ReadString('ProxyServer');
        chkEnabled.Checked:=Registry.ReadBool('ProxyEnable');
    finally
        Registry.Free;
    end;
end;

procedure TfrmMain.btnWriteClick(Sender: TObject);
var
    Registry: TRegistry;
begin
    Registry := TRegistry.Create(KEY_WRITE);
    try
        Registry.RootKey:= HKEY_CURRENT_USER;
        Registry.OpenKey('\Software\Microsoft\Windows\CurrentVersion\Internet Settings', False);
        Registry.WriteString('ProxyServer',edtProxy.Text);
        Registry.WriteBool('ProxyEnable',chkEnabled.Checked);
    finally
        Registry.Free;
    end;

    InternetSetOption(nil,INTERNET_OPTION_SETTINGS_CHANGED, nil,0);
end;
end.