TStrings.Strings Property

References the strings in the list by their positions.

Pascal

property Strings [Index: Integer]: string;

C++

__property AnsiString Strings[int Index];

Description

Descendants of TStrings must implement an accessor function for the Strings property to return the string at the position indicated by Index. Index gives the position of the string, where 0 is the first string, 1 is the second string, and so on.

Use the Strings property to get or set the string at a particular position.

To store a string as a name-value pair, assign Strings a value that includes the NameValueSeparator character. The name and value will then be accessible separately using the Names and Values properties.

Note: In Delphi, Strings is the default property of TStrings objects. The Strings identifier can be omitted when accessing the Strings property of a descendant of TStrings. For example, the following two lines of code are both acceptable and do the same thing:

MyStrings.Strings[0] := 'This is the first string';

MyStrings[0] := 'This is the first string';

C++ Examples:

Copy Code

/*
This example uses an Open dialog box, a memo, and a button
on a form. When the user clicks the button, the Open dialog
box appears. When the user selects files in the dialog box
and chooses the OK button, the first line from each of the
files is added to the memo. Choose multiple files using the
CNTL key or the SHIFT key.
*/

#include <stdio.h>     // for FILE

void __fastcall TForm1::Button1Click(TObject *Sender)
{
  FILE *stream;
  char FirstLine[512];
  
  OpenDialog1->Options.Clear();
  OpenDialog1->Options << ofAllowMultiSelect << ofFileMustExist;
  OpenDialog1->Filter = "Text files (*.txt)|*.txt|All files (*.*)|*.*";
  OpenDialog1->FilterIndex = 2; // start the dialog showing all files 
  if (OpenDialog1->Execute())
  {
    for (int I = 0; I < OpenDialog1->Files->Count; I ++)
    {
      stream = fopen(OpenDialog1->Files->Strings[I].c_str(), "r");
      if (stream)
      {
        // read the first line from the file
        fgets(FirstLine, sizeof(FirstLine), stream);
        Memo1->Lines->Append(FirstLine);
        fclose(stream);
      }
    }
  }
}

Copy Code

/*
The following example updates the strings in a list box
given the strings contained in another list box. If a string
in the source list box has the form Name=Value and the
destination list box contains a string with the same Name
part, the Value part in the destination list box will be
replaced by the source’s value.  TListBox objects that are
not name-value pairs are not assigned a Name and IndexOfName
will return -1.  TStrings Values are referenced using the
name AnsiString as an index.
*/
void MergeStrings(TStrings *Dest, TStrings *Source)
{
  for (int i = 0; i < Source->Count; i++)
  {
    if (Source->Strings[i].Pos("=") > 1)
    {
      int DI = Dest->IndexOfName(Source->Names[i]);
      if (DI > -1)
        Dest->Values[Source->Names[i]] = Source->Values[Source->Names[i]];
    }
  }
}

void __fastcall TForm1::Button1Click(TObject *Sender)
{
  MergeStrings(ListBox1->Items,ListBox2->Items);
}

void __fastcall TForm1::FormCreate(TObject *Sender)
{
  ListBox1->Items->Add("Plants = 10");
  ListBox1->Items->Add("Animals = 20");
  ListBox1->Items->Add("Minerals = 15");
  ListBox2->Items->Add("Animals = 4");
  ListBox2->Items->Add("Plants = 3");
  ListBox2->Items->Add("Minerals = 78");
}

Copy Code

/*
This example uses a button and a memo control on a form.
When the user clicks the button, the content of the specified
file is loaded into the memo, and the fifth line of the file
is written across the top of the form.
*/
void __fastcall TForm1::Button1Click(TObject *Sender)
{
  Memo1->Lines->LoadFromFile("../readme.txt");
  Caption = Memo1->Lines->Strings[4];
}

Delphi Examples:

Copy Code

{
This example uses an Open dialog box, a memo, and a button
on a form. When the user clicks the button, the Open dialog
box appears. When the user selects files in the dialog box
and chooses the OK button, the first line from each of the
files is added to the memo. Choose multiple files using the
CNTL key or the SHIFT key.
}
procedure TForm1.Button1Click(Sender: TObject);
var
  I: integer;
  F: TextFile;
  FirstLine: string;
begin
  OpenDialog1.Options := [ofAllowMultiSelect, ofFileMustExist];
  OpenDialog1.Filter := 'Text files (*.txt)|*.txt|All files (*.*)|*.*';
  OpenDialog1.FilterIndex := 2; { start the dialog showing all files } 
  if OpenDialog1.Execute then
    with OpenDialog1.Files do
      for I := 0 to Count - 1 do
      begin
        AssignFile(F, Strings[I]);  { next file in Files property }
        Reset(F);
        Readln(F, FirstLine);  { Read the first line out of the file }
        Memo1.Lines.Append(FirstLine);  { Add the line to the memo }
        CloseFile(F);
      end;
end;

Copy Code

{
The following example updates the strings in a list box
given the strings contained in another list box. If a string
in the source list box has the form Name=Value and the
destination list box contains a string with the same Name
part, the Value part in the destination list box will be
replaced by the source’s value.  TListBox objects that are
not name-value pairs are not assigned a Name and IndexOfName
will return -1.
}
procedure MergeStrings(Dest, Source: TStrings);
var
  I, DI: Integer;
  begin
  for I := 0 to Source.Count - 1 do
  begin
    if Pos ('=', Source[I]) > 1 then
    begin
      DI := Dest.IndexOfName(Source.Names[I]);
      if DI > -1 then Dest[DI] := Source[I];
    end;
  end;
end;

procedure TForm1.Button1Click(Sender: TObject);
begin
  MergeStrings(ListBox1.Items, ListBox2.Items);
end;

procedure TForm1.FormCreate(Sender: TObject);
begin
  ListBox1.Items.Add('Plants = 10');
  ListBox1.Items.Add('Animals = 20');
  ListBox1.Items.Add('Minerals = 15');
  ListBox2.Items.Add('Animals = 4');
  ListBox2.Items.Add('Plants = 3');
  ListBox2.Items.Add('Minerals = 78');
end;