Mega Code Archive
How to add a built in editor to a TListBox
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Title: How to add a built - in editor to a TListBox
Question: When using a TListBox and when a user can or must modify an item of the list usually you must add another TEdit control to get the value of the selected item and after the user has set the value he wants you have to update the item by code.
Well here is a solution for you to implement an editor that appears on the item you want to edit and lets you edit the item and by pressing enter you can save the value of the item.
Answer:
{*******************************************************}
{ }
{ GT Delphi Components }
{ ListBox Inplace Editor Demo }
{ }
{ Copyright (c) GT Delphi Components }
{ http://www.gtdelphicomponents.gr }
{ }
{ }
{*******************************************************}
unit Unit1;
interface
uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, StdCtrls;
type
TForm1 = class(TForm)
ListBox1: TListBox;
Button1: TButton;
chkBoxAllowEdit: TCheckBox;
procedure ListBox1Click(Sender: TObject);
procedure Button1Click(Sender: TObject);
private
{ Private declarations }
protected
FListBoxEditor : TEdit;
procedure DisplayEditor(AListBox : TListBox);
procedure InternalOnExit(Sender : TObject);
procedure InternalOnKeyPress(Sender : TObject;var Key: Char);
public
{ Public declarations }
end;
var
Form1: TForm1;
implementation
{$R *.dfm}
{-----------------------------------------------------------------------------}
procedure TForm1.ListBox1Click(Sender: TObject);
begin
//If we allow editing
if chkBoxAllowEdit.Checked then
begin
DisplayEditor(TListBox(Sender));
end;
end;
{-----------------------------------------------------------------------------}
procedure TForm1.DisplayEditor(AListBox: TListBox);
begin
//Checking if really an item is selected
if AListBox.ItemIndex =0 then
begin
//If the editor is not created we are creating it for the first time
if not Assigned(FListBoxEditor) then
begin
FListBoxEditor := TEdit.Create(Self);
FListBoxEditor.Parent := AListBox;
FListBoxEditor.OnExit := InternalOnExit;
FListBoxEditor.OnKeyPress := InternalOnKeyPress;
end;
//Setting The Color
FListBoxEditor.Color := clSkyBlue;
//This is crusial it places the editor exactly at the selected item
FListBoxEditor.BoundsRect := AListBox.ItemRect(AListBox.ItemIndex);
//Get the text of the item
FListBoxEditor.Text := AListBox.Items[AListBox.ItemIndex];
//Show the editor;
FListBoxEditor.Visible := True;
end;
end;
{-----------------------------------------------------------------------------}
procedure TForm1.InternalOnExit(Sender: TObject);
begin
//TEdit(Sender).Visible := False;
end;
{-----------------------------------------------------------------------------}
procedure TForm1.InternalOnKeyPress(Sender: TObject; var Key: Char);
begin
//if the Enter key is pressed
if key = #13 then
begin
//Set the new text for the selected item
ListBox1.Items[ListBox1.ItemIndex] := TEdit(Sender).Text;
//hide the editor
TEdit(Sender).Visible := False;
//Set focus to the listbox
ListBox1.SetFocus;
ListBox1.ItemIndex :=ListBox1.ItemIndex;
chkBoxAllowEdit.Checked := False;
end;
end;
{-----------------------------------------------------------------------------}
procedure TForm1.Button1Click(Sender: TObject);
begin
Close;
end;
{-----------------------------------------------------------------------------}
end.
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