TStrings.Assign Method

Sets the strings in the list, and possibly associated objects, from a source object.

Pascal

procedure Assign(Source: TPersistent); override;

C++

virtual __fastcall Assign(TPersistent * Source);

Description

Use Assign to set the value of the TStrings object from another object. If Source is of type TStrings, the list is set to the list of the source TStrings object, and if associated objects are supported, any associated objects are copied from the Source as well.

If Source is not of type TStrings, the inherited Assign will set the value of the list from any object that supports TStrings in its AssignTo method.

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]);
    TabControl1Change(Sender);
  }
}

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]);
}

Copy Code

/*
This example creates a stringlist, adds elements to it and
assigns the strings to items of a combo box.
*/

#include <memory>       //for STL auto_ptr class

void __fastcall TForm1::Button1Click(TObject *Sender)
{
  std::auto_ptr<TStrings> StringList(new TStringList());
  StringList->Add("This example uses A string List. ");
  StringList->Add("It is the easiest way to add strings");
  StringList->Add("to a combobox's list of strings. ");
  StringList->Add("Always remember TStrings is abstract,");
  StringList->Add("So create a TStringList instead.");
  ComboBox1->Width = 210;
  ComboBox1->Items->Assign(StringList.get());
  ComboBox1->ItemIndex = 0;
}

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]);
    TabControl1Change(Sender);
  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;

Copy Code

{
This example creates a stringlist, adds elements to it and
assigns the strings to items of a combo box.
}
procedure TForm1.Button1Click(Sender: TObject);
var
  StringList: TStringList;
begin
  StringList := TStringList.Create;
  try
    with StringList do begin
      Add('This example uses A string List.');
      Add('It is the easiest way to add strings');
      Add('to a combobox''s list of strings.');
      Add('Always remember TStrings.Create method');
      Add('is abstract; So use TStringList.Create');
      Add('method instead.');
    end;
    with ComboBox1 do begin
      Width := 210;
      Items.Assign(StringList);
      ItemIndex := 0;
    end;
  finally
    StringList.free;
  end;
end;