Scalabium Software

#65:How can I save/restore the component into BLOB-field?

Sometimes in applications you must save the component into BLOB-field of the own table and in run-time to restore it. For example, to save the report form and in run-time the end-user will select the wished report before report generation.

The next two procedure allows to save the component with all properties and restore it.

procedure SaveCompToBlob(AField: TBlobField; AComponent: TComponent);
var
  Stream: TBlobStream;
  CompName: string;
begin
  CompName := Copy(AComponent.ClassName, 2, 99);
  Stream := TBlobStream.Create(AField, bmWrite);
  try
    Stream.WriteComponentRes(CompName, AComponent);
  finally
    Stream.Free;
  end;
end;

procedure LoadCompFromBlob(AField: TBlobField; AComponent: TComponent);
var
  Stream: TBlobStream;
  i: integer;
begin
  try
    Stream := TBlobStream.Create(AField, bmRead);
    try
      {delete the all child components}
      for i := AComponent.ComponentCount - 1 downto 0 do
        AComponent.Components[i].Free;
      Stream.ReadComponentRes(AComponent);
    finally
      Stream.Free;
    end;
  except
    on EFOpenError do {nothing};
  end;
end;

Copyrightc 1998-2008, Scalabium Software. All rights reserved.
webmaster@scalabium.com

February 11, 2000