Pulling Text From a Memo Box Line by Line

Question

I need to go through a ton of data that is stored in a paradox table within a Memo field. I need to process this data line by line and process each line.

How can I tell Delphi to fetch each line in the memo field one by one?

Could I use #13#10 as a delimiter?

Answer 1

Assuming that what is in the memo field uses #13#10 as the line separator then I would use a TStringList, and the very useful Text property to split the memo field text into separate lines:

var
  StringList: TStringList;
  Line: string;
.....
StringList.Text := MemoFieldText;
for Line in StringList do
  Process(Line);

Even if your memo field uses Unix linefeeds then this code will interpret the memo field correctly.

Answer 2

It depends on how the field is actually declared in Paradox. If it's a TMemoField, it's pretty easy:

var
  SL: TStringList;
  Line: string;
begin
  SL := TStringList.Create;
  try
    SL.Text := YourMemoField.GetAsString;
    for Line in SL do
     // Process each line of text using `Line`
  finally
    SL.Free;
  end;
end;

If it's a TBlobField, it's a little more complicated. You need to read the memo field using a TBlobStream, and load the content of that stream into a TStringList:

// For Delphi versions that support it:
procedure LoadBlobToStringList(const DS: TDataSet; const FieldName: string;
  const SL: TStringList);
var
  Stream: TStream;
begin
  Assert(Assigned(SL), 'Create the stringlist for LoadBlobToStringList!');
  SL.Clear;
  Stream := DS.CreateBlobStream(DS.FieldByName(FieldName), bmRead);
  try
    SL.LoadFromStream(Stream);
  finally
    Stream.Free;
  end;
end;

// For older Delphi versions that do not have TDataSet.CreateBlobStream
procedure LoadBlobToStringList(const DS: TDataSet; const TheField: TField; 
  const SL: TStringList);
var
  BlobStr: TBlobStream;
begin
  Assert(Assigned(SL), 'Create the stringlist for LoadBlobToStringList!');
  SL.Clear;
  BlobStr := TBlobStream.Create(DS.FieldByName(TheField), bmRead);
  try
    SL.LoadFromStream(BlobStr);
  finally
    BlobStr.Free;
  end;
end;

// Use it
var
  SL: TStringList;
  Line: string;
begin
  SL := TStringList.Create;
  LoadBlobToStringList(YourTable, YourMemoFieldName, SL);
  for Line in SL do
    // Process each Line, which will be the individual line in the blob field

  // Alternatively, for earlier Delphi versions that don't support for..in
  // declare an integer variable `i`
  for i := 0 to SL.Count - 1 do
  begin
    Line := SL[i];
    // process line of text using Line
  end;
end;