ListView Spaltenbreite bei Form onResize neu berechnen?

[t.roller]

http://stackoverflow.com/questions/9...n-virtual-mode

Delphi-Quellcode:

//   List View Column Autosize (Virtual Mode)   
unit Unit1;

interface

uses
//  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, StdCtrls,
//  Forms, Dialogs, StrUtils, ComCtrls, CommCtrl;
  Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes,
  Vcl.Graphics, Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.ComCtrls, Winapi.CommCtrl,
  Vcl.StdCtrls, System.StrUtils, Vcl.ExtCtrls;

type
  TSampleRecord = record
    Column1: string;
    Column2: string;
    Column3: string;
    Column4: string;
  end;
  TSampleArray = array [0..49] of TSampleRecord;

type
  TForm1 = class(TForm)
    Button1: TButton;
    ListView1: TListView;
    Panel1: TPanel;
    procedure FormCreate(Sender: TObject);
    procedure Button1Click(Sender: TObject);
    procedure FormResize(Sender: TObject);
  private
    SampleArray: TSampleArray;
    procedure AutoResizeColumn(const AListView: TListView;
      const AColumn: Integer);
    procedure OnListViewData(Sender: TObject; Item: TListItem);
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

//   TForm1.AutoResizeColumn - auto-size column   
// AListView - list view object instance
// AColumn - index of the column to be auto-sized

procedure TForm1.AutoResizeColumn(const AListView: TListView;
  const AColumn: Integer);
var
  S: string;
  I: Integer;
  MaxWidth: Integer;
  ItemWidth: Integer;
begin
  // set the destination column width to the column's caption width
  // later on we'll check if we have a wider item
  MaxWidth := ListView_GetStringWidth(AListView.Handle,
    PChar(AListView.Columns.Items[AColumn].Caption));
  // iterate through all data items and check if their captions are
  // wider than the currently widest item if so then store that value
  for I := 0 to High(SampleArray) do
  begin
    case AColumn of
      0: S := SampleArray[I].Column1;
      1: S := SampleArray[I].Column2;
      2: S := SampleArray[I].Column3;
      3: S := SampleArray[I].Column4;
    end;
    ItemWidth := ListView_GetStringWidth(AListView.Handle, PChar(S));
    if MaxWidth < ItemWidth then MaxWidth := ItemWidth;
  end;
  // here is hard to say what value to use for padding to prevent the
  // string to be truncated; I've found the suggestions to use 6 px
  // for item caption padding and 12 px for subitem caption padding,
  // but a few quick tests confirmed me to use at least 7 px for items
  // and 14 px for subitems
  if AColumn = 0 then
    MaxWidth := MaxWidth + 7
  else
    MaxWidth := MaxWidth + 14;
  // and here we set the column width with caption padding included
  AListView.Columns.Items[AColumn].Width := MaxWidth;
end;

//   TForm1.FormCreate - setup the list view and fill custom data   
procedure TForm1.FormCreate(Sender: TObject);
var
  I: Integer;
begin
  ListView1.ViewStyle := vsReport;
  ListView1.Columns.Add.Caption := 'Column 1';
  ListView1.Columns.Add.Caption := 'Column 2';
  ListView1.Columns.Add.Caption := 'Column 3';
  ListView1.Columns.Add.Caption := 'Column 4';
  ListView1.OwnerData := True;
  ListView1.OnData := OnListViewData;
  ListView1.Items.Count := High(SampleArray);

  for I := 0 to High(SampleArray) do
  begin
    SampleArray[I].Column1 := 'Cell [0, ' + IntToStr(I) + '] ' +
      DupeString('x', I);
    SampleArray[I].Column2 := 'Cell [1, ' + IntToStr(I) + '] ' +
      DupeString('x', High(SampleArray) - I);
    SampleArray[I].Column3 := 'Cell [2, ' + IntToStr(I) + '] ' +
      DupeString('x', I);
    SampleArray[I].Column4 := 'Cell [3, ' + IntToStr(I) + '] ' +
      DupeString('x', High(SampleArray) - I);
  end;
end;

//   TForm1.FormCreate - custom handler for OnData event   
procedure TForm1.OnListViewData(Sender: TObject; Item: TListItem);
begin
  Item.Caption :=   SampleArray[Item.Index].Column1;
  Item.SubItems.Add(SampleArray[Item.Index].Column2);
  Item.SubItems.Add(SampleArray[Item.Index].Column3);
  Item.SubItems.Add(SampleArray[Item.Index].Column4);
end;

//   TForm1.Button1Click - auto-resize all 4 columns   
procedure TForm1.Button1Click(Sender: TObject);
begin
  AutoResizeColumn(ListView1, 0);
  AutoResizeColumn(ListView1, 1);
  AutoResizeColumn(ListView1, 2);
  AutoResizeColumn(ListView1, 3);
end;

procedure TForm1.FormResize(Sender: TObject);
begin
  Button1.Click;
end;

end.