TTabControl.TabIndex Property

Identifies the selected tab on a tab control.

Pascal

property TabIndex: Integer;

C++

__property int TabIndex;

Description

Read TabIndex to determine which tab was selected by the user. TabIndex is the index of the tab in the list of labels maintained by the Tabs property. The first (leftmost) tab has a TabIndex of 0, the next has 1, and so on. If no tabs are selected, TabIndex has a value of -1.

Set TabIndex to programmatically change the selected tab in the tab control.

C++ Examples:

Copy Code

/*
This example uses a tab control to display the contents of
several files. To run the example, place a tab control on a
form and add a memo control that fits into its client area.
Be sure to leave enough room for the tabs when they appear.
Then add an OpenDialog and a button to the form.  The
"Add a file" button adds a single file to the tabcontrol.
The "Assign files" button removes previous files and can be
used to assign multiple files.  To assign multiple files,
use CNTL Select or SHIFT Select to select files in the
OpenDialog.
*/
void __fastcall TForm1::Add_a_fileClick(TObject *Sender)
{
  OpenDialog1->Options << ofAllowMultiSelect << ofFileMustExist << ofHideReadOnly;
  if (OpenDialog1->Execute())
  {
    int index = TabControl1->Tabs->Add(OpenDialog1->FileName);
    Memo1->Lines->LoadFromFile(TabControl1->Tabs->Strings[index]);
  }
}

void __fastcall TForm1::Assign_filesClick(TObject *Sender)
{
  OpenDialog1->Options << ofAllowMultiSelect << ofFileMustExist << ofHideReadOnly;
  if (OpenDialog1->Execute())
  {
    TabControl1->Tabs->Assign(OpenDialog1->Files);
    Memo1->Lines->LoadFromFile(TabControl1->Tabs->Strings[TabControl1->TabIndex]);
  }
}
/*
Place the following code in the tab control’s OnChange event
handler:
*/
void __fastcall TForm1::TabControl1Change(TObject *Sender)
{
    Memo1->Lines->LoadFromFile(
      TabControl1->Tabs->Strings[TabControl1->TabIndex]);
}

Delphi Examples:

Copy Code

{
This example uses a tab control to display the contents of
several files. To run the example, place a tab control on a
form and add a memo control that fits into its client area.
Be sure to leave enough room for the tabs when they appear.
Then add an OpenDialog and a button to the form.  The
"Add a file" button adds a single file to the tabcontrol.
The "Assign files" button removes previous files and can be
used to assign multiple files.  To assign multiple files,
use CNTL Select or SHIFT Select to select files in the
OpenDialog.
}
procedure TForm1.Add_a_fileClick(Sender: TObject);
var index : integer;
begin
  OpenDialog1.Options :=
    [ofAllowMultiSelect, ofFileMustExist, ofHideReadOnly];
  if OpenDialog1.Execute then
  begin
    index:= TabControl1.Tabs.Add(OpenDialog1.FileName);
    Memo1.Lines.LoadFromFile(TabControl1.Tabs[index]);
  end;
end;

procedure TForm1.Assign_filesClick(Sender: TObject);
var index : integer;
begin
  OpenDialog1.Options :=
    [ofAllowMultiSelect, ofFileMustExist, ofHideReadOnly];
  if OpenDialog1.Execute then
  begin
    TabControl1.Tabs.Assign(OpenDialog1.Files);
    Memo1.Lines.LoadFromFile(
      TabControl1.Tabs[TabControl1.TabIndex]);
  end;
end;

{
Place the following code in the tab control’s OnChange event
handler:
}
procedure TForm1.TabControl1Change(Sender: TObject);
begin
  with TabControl1 do
    Memo1.Lines.LoadFromFile(Tabs[TabIndex]);
end;