以下使用自定义截取字符串语句总是取不到，是哪没声明？

unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, DB, ADODB, Grids, DBGrids, StdCtrls, FileCtrl;

type
  TForm1 = class(TForm)
    Label1: TLabel;
    Edit1: TEdit;
    Button1: TButton;
    Button2: TButton;
    GroupBox1: TGroupBox;
    DBGrid1: TDBGrid;
    ADOTable1: TADOTable;
    DataSource1: TDataSource;
    OpenDialog1: TOpenDialog;
    ADOConnection1: TADOConnection;
    Memo1: TMemo;
    procedure FormCreate(Sender: TObject);
    procedure Button1Click(Sender: TObject);
    procedure Button2Click(Sender: TObject);
  private
    { Private declarations }
    Function RegulateStr(aString:String;Sepchar:String):String;
    Function GetSubStr(var aString:String;SepChar:String):string;
    Function GetSubStrnum(aString:String;SepChar:String):integer;
  public
    { Public declarations }
  end;

var
  Form1: TForm1;
  s,s1:string;
  const Space='';

implementation

{$R *.dfm}

procedure TForm1.FormCreate(Sender: TObject);
var                //创建时联接并打开数据库显示到DBGrid1中
  connectstr:string;
begin
  connectstr:=GetCurrentDir+'\GDK.MDB;';
  ADOTable1.ConnectionString:=
    'Provider=Microsoft.Jet.OLEDB.4.0;Data Source='+connectstr+'Persist Security Info=False';
  ADOTable1.TableName:='a';
  ADOTable1.Active:=true;
  memo1.Lines.Clear;
end;

procedure TForm1.Button1Click(Sender: TObject);
var              //选择并打开文本文件
  f:file of Byte;
  l,wz:integer;
begin
  AssignFile(f, OpenDialog1.FileName);//打开选择的文件
  opendialog1.execute;
  Edit1.Text:=OpenDialog1.FileName;
  s1:=Edit1.Text;
  l:=length(s1);
  wz:=LastDelimiter('\',s1);
  s1:=copy(s1,wz+1,l-wz);//取目录中井名作s1井号识别。
  memo1.Lines.Clear;
  memo1.Lines.LoadFromFile(s1);
  memo1.ScrollBars:=ssVertical;
end;

procedure TForm1.Button2Click(Sender: TObject);
var
  i:Integer;
  MyLine:String;
begin
  //nbsp;
  with ADOTable1 do
  begin
    for i:=0 to memo1.Lines.Count-1 do
    begin
      MyLine:=RegulateStr(memo1.Lines[i],Space);

      //for j:=1 to Num do
      //begin
        ADOTable1.Append;
        ADOTable1.FieldByName('LJSJ').AsFloat:=StrToFloat(GetSubStr(MyLine,Space));
        ADOTable1.FieldByName('YL').AsFloat:=StrToFloat(GetSubStr(MyLine,Space));
        ADOTable1.Post;
      //end;
    end;
  end;
end;

function TForm1.RegulateStr(aString, Sepchar: String): String;
var
  i,Num:Integer;
  Flag:Boolean;
  MyStr,TempStr:String;
begin
  Flag:=False;//进行标志，去除多余的分割符
  Num:=Length(aString);//计算aString串的长度
  for i:=1 to Num do
  begin
    TempStr:=Copy(aString,i,1);//取aString串中的一字符
    if TempStr<>SepChar then
    begin
      MyStr:=MyStr+Tempstr;
      Flag:=True;
    end
    else
      if(Flag=True)then
      begin
        Mystr:=Mystr+TempStr;
        Flag:=False;
      end;
    end;
    if MyStr[Length(MyStr)]<>SepChar then
       MyStr:=MyStr+SepChar;
    RegulateStr:=MyStr;                  //现在的MyStr的内容是文本数据第一行的内容

      //showmessage(IntToStr(Num));
      //showmessage(RegulateStr);          //显示RegulateStr的内容时出错："Not enough actual parameters"
      //exit;

end;

function TForm1.GetSubStr(var aString: String; SepChar: String): string;
var
   Mystr:String;
   SepCharPos:Integer;
begin
  sepCharpos:=pos(sepchar,astring);//计算分割符在子串中的位置
  MyStr:=Copy(aString,1,SepCharPos-1);//将分割符前所有字符放到mystr串中

  {showmessage(IntToStr(sepCharpos)); //此处得0，？？？
  showmessage(astring);
  showmessage(MyStr);
  exit;}

  Delete(aString,1,SepCharPos);//除去分割符和分割符前的子串
  GetSubStr:=MyStr;//返回一个字段
end;

function TForm1.GetSubStrnum(aString, SepChar: String): integer;
var
  i:Integer;
  StrLen:Integer;
  Num:Integer;
begin
  StrLen:=Length(aString);//计算aString串的长度

      //showmessage(IntToStr(StrLen));
      //showmessage(GetSubStr);
      //exit;


  Num:=0;
  for i:=1 to StrLen do
  if Copy(aString,i,1)=SepChar then
     Num:=Num+1;
  GetSubStrNum:=Num;
end;

end.