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标题 在Listbox中增加背景图
范文
    1. 建立一个窗体
    2. 放一个ComboBox和Listbox
    3. 改变Component的Style为csOwnerDrawVariable和ListBox的Style为lbOwnerDrawVariable。
    4. 声明5个TBitmap的全局变量
    5. 覆盖Form的OnCreate.
    6. 覆盖ComboBox的OnDraw.
    7. 覆盖ComboBox的OnMeasureItem.
    8. 释放资源在Form的OnClose.
    unit Ownerdrw;
    interface
    uses
    SysUtils, WinTypes, WinProcs, Messages, Classes, Graphics, Controls,
    Forms, Dialogs, StdCtrls;
    type
    TForm1 = class(TForm)
    ComboBox1: TComboBox;
    ListBox1: TListBox;
    procedure FormCreate(Sender: TObject);
    procedure FormClose(Sender: TObject; var Action: TCloseAction);
    procedure ComboBox1DrawItem(Control: TWinControl; Index: Integer;
    Rect: TRect; State: TOwnerDrawState);
    procedure ComboBox1MeasureItem(Control: TWinControl; Index: Integer;
    var Height: Integer);
    procedure ListBox1DrawItem(Control: TWinControl; Index: Integer;
    Rect: TRect; State: TOwnerDrawState);
    procedure ListBox1MeasureItem(Control: TWinControl; Index: Integer;
    var Height: Integer);
    private
    { Private declarations }
    public
    { Public declarations }
    end;
    var
    Form1: TForm1;
    TheBitmap1, TheBitmap2, TheBitmap3, TheBitmap4,
    TheBitmap5 : TBitmap;
    implementation
    {$R *.DFM}
    procedure TForm1.FormCreate(Sender: TObject);
    begin
    TheBitmap1 := TBitmap.Create;
    TheBitmap1.LoadFromFile('C:delphiimagesuttonsglobe.bmp');
    TheBitmap2 := TBitmap.Create;
    TheBitmap2.LoadFromFile('C:delphiimagesuttonsvideo.bmp');
    TheBitmap3 := TBitmap.Create;
    TheBitmap3.LoadFromFile('C:delphiimagesuttonsgears.bmp');
    TheBitmap4 := TBitmap.Create;
    TheBitmap4.LoadFromFile('C:delphiimagesuttonskey.bmp');
    TheBitmap5 := TBitmap.Create;
    TheBitmap5.LoadFromFile('C:delphiimagesuttonsools.bmp');
    ComboBox1.Items.AddObject('Bitmap1: Globe', TheBitmap1);
    ComboBox1.Items.AddObject('Bitmap2: Video', TheBitmap2);
    ComboBox1.Items.AddObject('Bitmap3: Gears', TheBitmap3);
    ComboBox1.Items.AddObject('Bitmap4: Key', TheBitmap4);
    ComboBox1.Items.AddObject('Bitmap5: Tools', TheBitmap5);
    ListBox1.Items.AddObject('Bitmap1: Globe', TheBitmap1);
    ListBox1.Items.AddObject('Bitmap2: Video', TheBitmap2);
    ListBox1.Items.AddObject('Bitmap3: Gears', TheBitmap3);
    ListBox1.Items.AddObject('Bitmap4: Key', TheBitmap4);
    ListBox1.Items.AddObject('Bitmap5: Tools', TheBitmap5);
    end;
    procedure TForm1.FormClose(Sender: TObject; var Action: TCloseAction);
    begin
    TheBitmap1.Free;
    TheBitmap2.Free;
    TheBitmap3.Free;
    TheBitmap4.Free;
    TheBitmap5.Free;
    end;
    procedure TForm1.ComboBox1DrawItem(Control: TWinControl; Index: Integer;
    Rect: TRect; State: TOwnerDrawState);
    var
    Bitmap: TBitmap;
    Offset: Integer;
    begin
    with (Control as TComboBox).Canvas do
    begin
    FillRect(Rect);
    Bitmap := TBitmap(ComboBox1.Items.Objects[Index]);
    if Bitmap <> nil then
    begin
    BrushCopy(Bounds(Rect.Left + 2, Rect.Top + 2, Bitmap.Width,
    Bitmap.Height), Bitmap, Bounds(0, 0, Bitmap.Width,
    Bitmap.Height), clRed);
    Offset := Bitmap.width + 8;
    end;
    { display the text }
    TextOut(Rect.Left + Offset, Rect.Top, Combobox1.Items[Index])
    end;
    end;
    procedure TForm1.ComboBox1MeasureItem(Control: TWinControl; Index:
    Integer; var Height: Integer);
    begin
    height:= 20;
    end;
    procedure TForm1.ListBox1DrawItem(Control: TWinControl; Index: Integer;
    Rect: TRect; State: TOwnerDrawState);
    var
    Bitmap: TBitmap;
    Offset: Integer;
    begin
    with (Control as TListBox).Canvas do
    begin
    FillRect(Rect);
    Bitmap := TBitmap(ListBox1.Items.Objects[Index]);
    if Bitmap <> nil then
    begin
    BrushCopy(Bounds(Rect.Left + 2, Rect.Top + 2, Bitmap.Width,
    Bitmap.Height), Bitmap, Bounds(0, 0, Bitmap.Width,
    Bitmap.Height), clRed);
    Offset := Bitmap.width + 8;
    end;
    { display the text }
    TextOut(Rect.Left + Offset, Rect.Top, Listbox1.Items[Index])
    end;
    end;
    procedure TForm1.ListBox1MeasureItem(Control: TWinControl; Index: Integer;
    var Height: Integer);
    begin
    height:= 20;
    end;
    end.
    //该窗体的DFM文件
    object Form1: TForm1
    Left = 211
    Top = 155
    Width = 435
    Height = 300
    Caption = 'Form1'
    Font.Color = clWindowText
    Font.Height = -13
    Font.Name = 'System'
    Font.Style = []
    PixelsPerInch = 96
    OnClose = FormClose
    OnCreate = FormCreate
    TextHeight = 16
    object ComboBox1: TComboBox
    Left = 26
    Top = 30
    Width = 165
    Height = 22
    Style = csOwnerDrawVariable
    ItemHeight = 16
    TabOrder = 0
    OnDrawItem = ComboBox1DrawItem
    OnMeasureItem = ComboBox1MeasureItem
    end
    object ListBox1: TListBox
    Left = 216
    Top = 28
    Width = 151
    Height = 167
    ItemHeight = 16
    Style = lbOwnerDrawVariable
    TabOrder = 1
    OnDrawItem = ListBox1DrawItem
    OnMeasureItem = ListBox1MeasureItem
    end
    end
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更新时间：2025/5/25 3:36:57