How to save a string to a .txt file in Delphi?
I need to make a program that generates a passw开发者_如何学JAVAord that is saved in a text file format in a specific destination I set and the user needs to open the .txt to get the password to 'unlock' another program.
I have already got the code to generate the password in the string sPass and now I need to use the SaveToFile function to save it into the text file I created called Password.txt but I cannot find the general form to use the SaveTo File Function in Delphi and I do not know where to put the sPass and Password.txt in the function.
It should be something like : SaveToFile(...) but I do not know how to save sPass in Password.txt
Edit :
Just one more question, how do you delete what is previously stored in Password.txt before you add the string to it so that Password.txt is blank before the string is added ? Thanks
The Modern Modern way is to use TFile.WriteAllText
in IOUtils (Delphi 2010 and up)
procedure WriteAllText(const Path: string; const Contents: string); overload; static;
Creates a new file, writes the specified string to the file, and then closes the file. If the target file already exists, it is overwritten.
The modern way is to create a stringlist and save that to file.
procedure MakeAStringlistAndSaveThat;
var
MyText: TStringlist;
begin
MyText:= TStringlist.create;
try
MyText.Add('line 1');
MyText.Add('line 2');
MyText.SaveToFile('c:\folder\filename.txt');
finally
MyText.Free
end; {try}
end;
Note that Delphi already has a related class that does everything you want: TInifile.
It stores values and keys in a key = 'value'
format.
passwordlist:= TInifile.Create;
try
passwordlist.LoadFromFile('c:\folder\passwords.txt');
//Add or replace a password for `user1`
passwordlist.WriteString('sectionname','user1','topsecretpassword');
passwordlist.SaveToFile('c:\folder\passwords.txt');
finally
passwordlist.Free;
end; {try}
Warning
Note that saving unecrypted passwords in a textfile is a security-leak. It's better to hash your passwords using a hashfunction, see: Password encryption in Delphi
For tips on how to save passwords in a secure way.
You can use the TFileStream
class to save a string to a file:
uses
Classes;
procedure StrToFile(const FileName, SourceString : string);
var
Stream : TFileStream;
begin
Stream:= TFileStream.Create(FileName, fmCreate);
try
Stream.WriteBuffer(Pointer(SourceString)^, Length(SourceString));
finally
Stream.Free;
end;
end;
and to read
function FileToStr(const FileName : string):string;
var
Stream : TFileStream;
begin
Stream:= TFileStream.Create(FileName, fmOpenRead);
try
SetLength(Result, Stream.Size);
Stream.Position:=0;
Stream.ReadBuffer(Pointer(Result)^, Stream.Size);
finally
Stream.Free;
end;
end;
Fastest and simplest way, no need to declare any variables:
with TStringList.Create do
try
Add(SomeString);
SaveToFile('c:\1.txt');
finally
Free;
end;
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