Question

我正在为我的朋友做一个抽奖活动。一切都很顺利但是当我删除一个值时，结果却在改变......请帮助我！

示例：

列表框;

1-A
2-C
3-B
4-F
5-H
6-J

删除第3行后：

1-A
2-C
4-F
5-H
6-J
6-G

我想要的是什么：

1-A
2-C
3-F
4小时
5-J
6-G

以下是代码：

unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls, ExtCtrls;

type
  TForm1 = class(TForm)
    ListBox1: TListBox;
    Label1: TLabel;
    ComboBox1: TComboBox;
    Edit1: TEdit;
    Button1: TButton;
    Label2: TLabel;
    ComboBox2: TComboBox;
    Label3: TLabel;
    Button2: TButton;
    Edit2: TEdit;
    Edit3: TEdit;
    Edit4: TEdit;
    Edit5: TEdit;
    Edit6: TEdit;
    Button3: TButton;
    Button4: TButton;
    SaveDialog1: TSaveDialog;
    OpenDialog1: TOpenDialog;
    Button5: TButton;
    Button6: TButton;
    procedure Button1Click(Sender: TObject);
    procedure Button2Click(Sender: TObject);
    procedure FormCreate(Sender: TObject);
    procedure Button3Click(Sender: TObject);
    procedure Button4Click(Sender: TObject);
    procedure Button5Click(Sender: TObject);
    procedure Button6Click(Sender: TObject);

  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;
  b,sayac:integer;
  sonkayit,deneme:integer;
implementation

{$R *.dfm}

procedure TForm1.FormCreate(Sender: TObject);
begin
sayac:=0;

listbox1.MultiSelect:=true;
end;

procedure TForm1.Button1Click(Sender: TObject);
begin
sayac:=sayac+1;

b:=listbox1.Count + 1;

listbox1.Items.Add(IntToStr(b) + ' ' + edit1.Text);
edit1.Text:='';
end;

procedure TForm1.Button2Click(Sender: TObject);
var
a:integer;
kisi:string;

begin
Randomize;
a:=Random(b);
kisi:= listbox1.Items.Strings[a];
edit2.Text:=(kisi);

if combobox1.ItemIndex=0 then
begin
edit2.Visible:=true;
edit3.Visible:=false;
edit4.Visible:=false;
edit5.Visible:=false;
edit6.Visible:=false;
end;

if combobox1.ItemIndex=1 then
begin
edit2.Visible:=true;
edit3.Visible:=true;
edit4.Visible:=false;
edit5.Visible:=false;
edit6.Visible:=false;
end;

if combobox1.ItemIndex=2 then
begin
edit2.Visible:=true;
edit3.Visible:=true;
edit4.Visible:=true;
edit5.Visible:=false;
edit6.Visible:=false;
end;

if combobox1.ItemIndex=3 then
begin
edit2.Visible:=true;
edit3.Visible:=true;
edit4.Visible:=true;
edit5.Visible:=true;
edit6.Visible:=false;
end;

if combobox1.ItemIndex=4 then
begin
edit2.Visible:=true;
edit3.Visible:=true;
edit4.Visible:=true;
edit5.Visible:=true;
edit6.Visible:=true;
end;
end;

procedure TForm1.Button3Click(Sender: TObject);
begin
savedialog1.FileName:='çekiliş';
if savedialog1.Execute then
begin
listbox1.Items.SaveToFile(savedialog1.FileName + '.txt');
end;
end;

procedure TForm1.Button4Click(Sender: TObject);
begin
if opendialog1.Execute then
begin
listbox1.Items.LoadFromFile(opendialog1.FileName);
end;
end;

procedure TForm1.Button5Click(Sender: TObject);
begin
listbox1.DeleteSelected;
end;

procedure TForm1.Button6Click(Sender: TObject);
begin
listbox1.Clear;
end;

end.

Answer 1

listbox1.Items.Add(IntToStr(b) + ' ' + edit1.Text); 而不是直接添加到列表框，将IntToStr(b)和edit1.Text分开存储在两个字符串列表中，并从字符串列表中填充列表框数据。

还从第二个stringlist中执行删除删除相应的索引，并在listbox中重新填充

或者您可以将edit1.Text存储在字符串列表中，并从列表框中删除您从列表框中删除的字符串。并使用索引+字符串组合填充列表框中的数据.....

Answer 2

我会在这里使用虚拟列表框。这些是基本步骤：

将数据存储在GUI控件以外的容器中，例如字符串列表。无论如何，这都是很好的做法。
将Style设置为lbVirtual。
在OnData事件处理程序上实现列表。它需要返回由索引和容器中的基础项组成的字符串。
删除项目时，将其从字符串列表容器中删除，并在列表框中调用Invalidate以强制执行绘制周期。该绘制周期将通过调用OnData来请求新值，并且您的代码可以提供更新的文本。
每当修改基础容器时，您必须通过设置列表框控件的Count属性让控件知道它显示的项目数。

这是一个非常简单的例子：

Pascal单位

unit Unit1;

interface

uses
  SysUtils, Classes, Controls, StdCtrls, Forms;

type
  TForm1 = class(TForm)
    List: TListBox;
    Delete: TButton;
    procedure FormCreate(Sender: TObject);
    procedure ListData(Control: TWinControl; Index: Integer; var Data: string);
    procedure DeleteClick(Sender: TObject);
  private
    FItems: TStringList;
  end;

implementation

{$R *.dfm}

procedure TForm1.FormCreate(Sender: TObject);
var
  c: Char;
begin
  FItems := TStringList.Create;
  for c := 'a' to 'z' do
    FItems.Add(c);
  List.Count := FItems.Count;
end;

procedure TForm1.ListData(Control: TWinControl; Index: Integer; 
  var Data: string);
begin
  Data := Format('%d %s', [Index+1, FItems[Index]]);
end;

procedure TForm1.DeleteClick(Sender: TObject);
var
  Index: Integer;
begin
  for Index := FItems.Count-1 downto 0 do
    if List.Selected[Index] then
      FItems.Delete(Index);
  List.Count := FItems.Count;
  List.Invalidate;
end;

end.

相关表单文件

object Form1: TForm1
  Left = 0
  Top = 0
  Caption = 'Form1'
  ClientHeight = 303
  ClientWidth = 307
  OnCreate = FormCreate
  PixelsPerInch = 96
  TextHeight = 13
  object List: TListBox
    Left = 8
    Top = 8
    Width = 201
    Height = 287
    Style = lbVirtual
    Anchors = [akLeft, akTop, akRight, akBottom]
    MultiSelect = True
    TabOrder = 0
    OnData = ListData
  end
  object Delete: TButton
    Left = 224
    Top = 8
    Width = 75
    Height = 23
    Anchors = [akTop, akRight]
    Caption = 'Delete'
    TabOrder = 1
    OnClick = DeleteClick
  end
end

列表框（列表错误）

2 个答案: