Title: How to circumvent the index not found Exception (dBASE table)
unit Fixit;
interface
uses
SysUtils, WinTypes, WinProcs, Messages, Classes, Graphics,
Controls, Forms, Dialogs, StdCtrls, DB, DBTables, Grids, DBGrids;
type
TForm1 = class(TForm)
Table1: TTable;
Button1: TButton;
procedure Button1Click(Sender: TObject);
private
{ Private declarations }
public
{ Public declarations }
end;
var
Form1: TForm1;
implementation
{$R *.DFM}
const
TheTableDir = 'c:\temp\';
TheTableName = 'animals.dbf';
procedure RemoveMDXByte(dbFile: string);
{ This procedure accepts a DBF file as a parameter. It will patch}
{ the DBF header, so that it no longer requires the MDX file }
const
Value: Byte = 0;
var
F: file of byte;
begin
AssignFile(F, dbFile);
Reset(F);
Seek(F, 28);
Write(F, Value);
CloseFile(F);
end;
procedure TForm1.Button1Click(Sender: TObject);
{ This procedure is called in response to a button click. It }
{ attempts to open a table, and, if it can't find the .MDX file, }
{ it patches the DBF file and re-execute the procedure to }
{ re-open the table without the MDX }
begin
try
{ set the directory for the table }
Table1.DatabaseName := ThheTableDir;
{ set the table name }
Table1.TableName := TheTableName;
{ attempt to open the table }
Table1.Open;
except
on E: EDBEngineError do
{ The following message indicates the MDX wasn't found: }
if Pos('Index does not exist. File', E.Message) 0 then
begin
{ Tell user what's going on. }
MessageDlg('MDX file not found.Attempting to Open
without Index.', mtWarning, [mbOK], 0);
{ remove the MDX byte from the table header }
RemoveMDXByte(TheTableDir + TheTableName);
{ Send the button a message to make it think it was }
{ pressed again. Doing so will cause this procedure to }
{ execute again, and the table will be opened without }
{ the MDX }
PostMessage(Button1.Handle, cn_Command, bn_Clicked, 0);
end;
end;
end;
end.