unit Unit1;

interface

uses

  Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,

  Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls, Vcl.ExtCtrls;

type

  TForm1 = class(TForm)

    Panel1: TPanel;

    Button1: TButton;

    Edit1: TEdit;

    Memo1: TMemo;

    Button2: TButton;

    procedure Button1Click(Sender: TObject);

    procedure Button2Click(Sender: TObject);

  private

    { Private declarations }

    function getmaxval(myarray: array of Integer):Integer;

  public

    { Public declarations }

  end;

var

  Form1: TForm1;

implementation

{$R *.dfm}

var

  rec: Integer = 0;

procedure TForm1.Button1Click(Sender: TObject);

var

  i,j,m,n,p:Integer;

  edt: TEdit;

  arr: array of Integer;

begin

  Inc(rec);  //按钮点击次数

  m := 0;

  n := 0;

  p := 0;

  Memo1.Clear;

  for i := 0 to Panel1.ControlCount - 1 do

  begin

    if Panel1.Controls[i] is TEdit then

    inc(m);  //记录edit个数

  end;

  SetLength(arr,m);

  Memo1.Lines.Add('创建组件前的记录:' + #13#10 + '--------------------------');

  Memo1.Lines.Add('Edit组件个数:' + IntToStr(m) + #13#10 + '--------------------------');

  for j := 0 to Panel1.ControlCount - 1 do

  begin

    if Panel1.Controls[j] is TEdit then

    begin

      if n <= m then

      begin

        arr[n] := TEdit(Panel1.Controls[j]).Top;

        Memo1.Lines.Add('Edit' + IntToStr(n + 1) + '的Top值:' + IntToStr(arr[n]));

        Inc(n);

      end else Break;

    end;

  end;

  p := getmaxval(arr); //记录panel里最下面的edit的top值

  Memo1.Lines.Add('最大Top值:' + inttostr(p));

  //动态创建Edit

  //TEdit.Create()，参数是一个AOwner: TComponent，只要是窗体上的组件都可以，

  //但必须要在创建后重新指明父组件的名称，否则没法显示

  edt := TEdit.Create(Panel1);  //指明了owner，可以不释放内存，窗口关闭时由父组件销毁

  edt.Parent := Panel1;

  edt.Left := Edit1.Left;

  edt.Top := p + Edit1.Height + 3;

  edt.Width := Edit1.Width;

  edt.Height := Edit1.Height;

  edt.Text := 'Edit' + IntToStr(rec + 1);

  edt.Show;

end;

procedure TForm1.Button2Click(Sender: TObject);  //释放内存，并初始化

var

  i,j,m:Integer;

  edts: array of TEdit;

begin

  j := 0;  //数组edts的键[key]

  SetLength(edts,rec + 1);  //button1次数 + 原有的edit1

  for i := 0 to Panel1.ControlCount - 1 do

  begin

    if Panel1.Controls[i] is TEdit then

    begin

      edts[j] := TEdit(Panel1.Controls[i]);

      Inc(j);

    end;

  end;

  for m := Length(edts) downto 1 do  //edit1不释放，注意此处的downto，根据栈后进先出原则，否则会报错

  begin

    try

      edts[m].Free;

      rec := 0;

      Memo1.Clear;

    except

      //ShowMessage('释放动态创建组件的内存失败！');

    end;

  end;

end;

function TForm1.getmaxval(myarray: array of Integer):Integer;  //遍历数组取得最大值

var

  i,max:Integer;

begin

  max := myarray[0];

  for i := 1 to Length(myarray) - 1 do

  begin

    if myarray[i] >= max then

    max := myarray[i];

  end;

  Result := max;

end;

end.