Still celebrating National IT Professionals Day with 3 months of free Premium Membership. Use Code ITDAY17

x
?
Solved

Read/Save contents

Posted on 2001-09-14
2
Medium Priority
?
227 Views
Last Modified: 2010-04-06
How can I use TStream to save and read the contents of 4 listboxs and 2 memos to "Demo.dat" file? Something like database. Exmaples please.
0
Comment
Question by:TCSCode
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
2 Comments
 
LVL 2

Expert Comment

by:bugroger
ID: 6483809
Hi,

Have a look at these two functions:

{
 SaveIT(ListBox1, ListBox2, ListBox3, ListBox4, Memo1, Memo2, 'C:\Demo.dat');
LoadIt(ListBox1, ListBox2, ListBox3, ListBox4, Memo1, Memo2, 'C:\Demo.dat');
}

Procedure SaveIT(LB1, LB2, LB3, LB4 : TListBox; M1, M2 : TMemo; FileName : String);
VAR
 FS           : TFileStream;
 DummyStream  : TMemoryStream;
 Size         : Integer;

Begin
 FS          := TFileStream.Create(FileName, fmCreate or fmSHAREDENYNONE);
 DummyStream := TMemoryStream.Create;

 LB1.Items.SaveToStream(DummyStream);
 Size := DummyStream.Size;
 FS.Write(Size, 4);
 FS.Write(DummyStream.Memory^, Size);

 LB2.Items.SaveToStream(DummyStream);
 Size := DummyStream.Size;
 FS.Write(Size, 4);
 FS.Write(DummyStream.Memory^, Size);

 LB3.Items.SaveToStream(DummyStream);
 Size := DummyStream.Size;
 FS.Write(Size, 4);
 FS.Write(DummyStream.Memory^, Size);

 LB4.Items.SaveToStream(DummyStream);
 Size := DummyStream.Size;
 FS.Write(Size, 4);
 FS.Write(DummyStream.Memory^, Size);

 M1.Lines.SaveToStream(DummyStream);
 Size := DummyStream.Size;
 FS.Write(Size, 4);
 FS.Write(DummyStream.Memory^, Size);

 M2.Lines.SaveToStream(DummyStream);
 Size := DummyStream.Size;
 FS.Write(Size, 4);
 FS.Write(DummyStream.Memory^, Size);

 DummyStream.Free;
 FS.Free;
End;

Procedure LoadIT(LB1, LB2, LB3, LB4 : TListBox; M1, M2 : TMemo; FileName : String);
VAR
 FS           : TFileStream;
 DummyStream  : TMemoryStream;
 Size         : Integer;

Begin
 FS          := TFileStream.Create(FileName, fmOpenRead or fmSHAREDENYNONE);
 DummyStream := TMemoryStream.Create;

 FS.Read(Size, 4);
 DummyStream.Size := Size;
 FS.Read(DummyStream.Memory^, Size);
 LB1.Items.LoadFromStream(DummyStream);

 FS.Read(Size, 4);
 DummyStream.Size := Size;
 FS.Read(DummyStream.Memory^, Size);
 LB2.Items.LoadFromStream(DummyStream);

 FS.Read(Size, 4);
 DummyStream.Size := Size;
 FS.Read(DummyStream.Memory^, Size);
 LB3.Items.LoadFromStream(DummyStream);

 FS.Read(Size, 4);
 DummyStream.Size := Size;
 FS.Read(DummyStream.Memory^, Size);
 LB4.Items.LoadFromStream(DummyStream);

 FS.Read(Size, 4);
 DummyStream.Size := Size;
 FS.Read(DummyStream.Memory^, Size);
 M1.Lines.LoadFromStream(DummyStream);

 FS.Read(Size, 4);
 DummyStream.Size := Size;
 FS.Read(DummyStream.Memory^, Size);
 M2.Lines.LoadFromStream(DummyStream);

 DummyStream.Free;
 FS.Free;
End;
0
 

Accepted Solution

by:
duti earned 1200 total points
ID: 6484085
const
  sFileName ='demo.dat';
{---------------------------------------------------------------------------
  TForm1.Button1Click
---------------------------------------------------------------------------}
procedure TForm1.Button1Click(Sender: TObject);
Begin
  // you can save as much listboxes/memos as you want,
  // without additional coding in the save/load routines.
  SaveData( [ ListBox1, Memo1, ListBox2, listbox3, Memo2 ] );
end;

{---------------------------------------------------------------------------
  TForm1.Button2Click
---------------------------------------------------------------------------}
procedure TForm1.Button2Click(Sender: TObject);
begin
  LoadData; // everything works automagically
end;

{---------------------------------------------------------------------------
  TForm1.SaveData
---------------------------------------------------------------------------}
procedure TForm1.SaveData(aComp : array of TComponent);
var
  stream : TFileStream;
  i      : integer;

  procedure _Save(const sName, sData : string);
  var iLength : integer;
  begin
    iLength := length(sName);
    stream.Write(iLength, sizeof(iLength));
    stream.Write(pchar(sName)^, length(sName));

    iLength := length(sData);
    stream.Write(iLength, sizeof(iLength));
    stream.Write(pchar(sData)^, length(sData));
  end;
begin
  stream := TFileStream.Create(sFileName, fmCreate or fmShareDenyNone);
  try
    for i := low(aComp) to high(aComp) do
      if aComp[i] is TListbox then _Save(aComp[i].Name, TListbox(aComp[i]).Items.Text)
      else if aComp[i] is TMemo then _Save(aComp[i].Name, TMemo(aComp[i]).Lines.Text);
  finally
    stream.Free;
  end;
end;

{---------------------------------------------------------------------------
  TForm1.LoadData
---------------------------------------------------------------------------}
procedure TForm1.LoadData;
var
  stream       : TFileStream;
  iLength      : integer;
  iBytesRead   : integer;
  sName        : string;
  sText        : string;
  Comp         : TComponent;
begin
  stream := TFileStream.Create(sFileName, fmOpenRead or fmShareDenyNone);
  try
    repeat
      iBytesRead := stream.Read(iLength, SizeOf(iLength));
      if iBytesRead > 0 then
        begin
          SetLength(sName, iLength);
          stream.Read(pchar(sName)^, iLength);

          stream.Read(iLength, SizeOf(iLength));
          SetLength(sText, iLength);
          stream.Read(pchar(sText)^, iLength);
          Comp := FindComponent(sName);
          if Comp <> nil then
            begin
              if Comp is TListBox then TListBox(Comp).Items.Text := sText
              else if Comp is TMemo then TMemo(Comp).Lines.Text := sText;
            end;
        end;
    until iBytesRead = 0;
  finally
    stream.Free;
  end;
end;
0

Featured Post

On Demand Webinar: Networking for the Cloud Era

Did you know SD-WANs can improve network connectivity? Check out this webinar to learn how an SD-WAN simplified, one-click tool can help you migrate and manage data in the cloud.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

This article explains how to create forms/units independent of other forms/units object names in a delphi project. Have you ever created a form for user input in a Delphi project and then had the need to have that same form in a other Delphi proj…
In this tutorial I will show you how to use the Windows Speech API in Delphi. I will only cover basic functions such as text to speech and controlling the speed of the speech. SAPI Installation First you need to install the SAPI type library, th…
In this video, Percona Solution Engineer Rick Golba discuss how (and why) you implement high availability in a database environment. To discuss how Percona Consulting can help with your design and architecture needs for your database and infrastr…
How to fix incompatible JVM issue while installing Eclipse While installing Eclipse in windows, got one error like above and unable to proceed with the installation. This video describes how to successfully install Eclipse. How to solve incompa…
Suggested Courses

722 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question