关于操作ini文件的问题

请帮着看看这段代码！我对如何操作ini文件一点不清楚，在一个实例的书中有这么段代码，但是却做不出书上的效果。请高手指点一下，告诉我下面几个关于操ini文件的语句怎么用？？或者能提供相关这方面的资料也行，我的QQ（42189737），谢谢谢谢！

unit Student_frm;

interface

uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, ToolWin, ComCtrls, Buttons, Grids, DBGrids, DB, DBTables,
ExtCtrls, DBCtrls, StdCtrls,IniFiles;

type
TFrmStudent = class(TForm)
CoolBar1: TCoolBar;
sbADD: TSpeedButton;
sbQuery: TSpeedButton;
sbChart: TSpeedButton;
sbOption: TSpeedButton;
sbAbout: TSpeedButton;
sbClose: TSpeedButton;
DBGrid1: TDBGrid;
Table1: TTable;
dsTable: TDataSource;
DBNavigator1: TDBNavigator;
btnState: TButton;
Label1: TLabel;
edtStuno: TEdit;
Query1: TQuery;
dsQuery: TDataSource;
procedure FormCreate(Sender: TObject);
procedure btnStateClick(Sender: TObject);
private
{ Private declarations }
public
{ Public declarations }
end;

var
FrmStudent: TFrmStudent;
IniFile:TIniFile; //TIniFile类型变量（需引入IniFiles单元），用于操作ini文件
FieldName:string; //保存字段名称
i,j:integer;
FieldVisible:Boolean; //标识字段在网格中是否可见
SQLCond:string; //查询条件
IniFileName:string;
AFieldCound:Integer;
implementation

{$R *.dfm}

procedure TFrmStudent.FormCreate(Sender: TObject);
begin
SQLCond :=''; //初始化查询条件
//创建由全局的Ini文件名变量IniFileName指定的IniFile对象
IniFile:=TIniFile.Create(IniFileName);
//读入试题个数，该值保存在Ini文件的DBStructure节中
AFieldCound:=IniFile.ReadInteger('DBStructure','试题数',1);
for i:=0 to Query1.FieldCount-1 do
begin
FieldName:=Query1.Fields[i].FieldName; //取出字段名
//对于索引大于试题总数的字段则不网格中不显示
//其中AFieldCount+3原因是在“第一题”字段前还有三个字段
if i>AFieldCound+3 then
FieldVisible:=false
else //否则从配置文件中取出该字段的可见状态
FieldVisible:=Inifile.ReadBool('Display',FieldName,False);
//设定网格中第i列的可见性
DbGrid1.Columns[i].Visible:=FieldVisible;
end;
IniFile.Free;
end;