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LazyMAPI # 6

Test TMAPITable wrapper, FastFilter and FastSort

With this example, we intoduce the Delphi TMAPITable class, which is IMAPITable wrapper.
It does not cover all of the properties and functions of IMAPITable, but provides easy access „in Delphi way“.

usage:

unit uMain;
 
{
 Please add
 ..\..\Library;..\..\Library\Helpers;..\Forms;
 to project search path
}
 
interface
 
uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls, ExtCtrls, Buttons, ComCtrls, ImgList, Menus, ExtendedMAPI, IMIEMTypes;
 
type
  TfrmMain = class(TForm)
    plTOP: TPanel;
    btLogOn: TSpeedButton;
    btLogOff: TSpeedButton;
    rgProfile: TRadioGroup;
    MessageListIcons: TImageList;
    StatusBar: TStatusBar;
    FolderListIcons: TImageList;
    Splitter1: TSplitter;
    MessageListView: TListView;
    MailboxTreeView: TTreeView;
    btFastMdgFilter: TButton;
    procedure btLogOnClick(Sender: TObject);
    procedure btLogOffClick(Sender: TObject);
    procedure FormCreate(Sender: TObject);
    procedure FormClose(Sender: TObject; var Action: TCloseAction);
    procedure MailboxTreeViewExpanding(Sender: TObject; Node: TTreeNode; var AllowExpansion: Boolean);
    procedure MailboxTreeViewCollapsing(Sender: TObject; Node: TTreeNode; var AllowCollapse: Boolean);
    procedure MailboxTreeViewChange(Sender: TObject; Node: TTreeNode);
    procedure MessageListViewColumnClick(Sender: TObject; Column: TListColumn);
    procedure MessageListViewData(Sender: TObject; Item: TListItem);
    procedure MessageListViewDblClick(Sender: TObject);
    procedure btFastMdgFilterClick(Sender: TObject);
  private
    { Private declarations }
    hr: HRESULT;
    MAPISession: IMAPISession;
    MAPIStore: IMsgStore;
    DATAFolder: IMAPIFolder;
 
    procedure ClearMAPIObjects;
    procedure BuildFolderTree;
    procedure ExpandLevel(Node: TTreeNode);
    procedure CollapseLevel(Node: TTreeNode);
    procedure CheckStore(StoreID: TBytes);
    procedure GetMessages(P: Pointer);
  public
    { Public declarations }
  end;
 
var
  frmMain: TfrmMain;
 
implementation
 
 
uses DateUtils, EDK, MAPIUtils, MAPIException, MAPISessionUtils, MAPIFldUtils, MAPIPropUtils,
  MAPITable, MessageFrm;
{$R *.dfm}
 
var
  SpecialFoldersList: TSpecialFoldersList = nil;
  MessagesTable: TMAPITable = nil;
 
  ColumnIndex: Integer = -1;
 
  SortAscending: Boolean = True;
  ColumnTag: Cardinal = 0;
 
  SortAscendingOld: Boolean = True;
  ColumnTagOld: Cardinal = 0;
 
  FolderID: TBytes = nil;
 
 
procedure ClearSpecialFoldersList;
var
  iCount: Integer;
begin
  for iCount := 0 to Length(SpecialFoldersList) - 1 do
    SpecialFoldersList[iCount].EntryID := nil;
  SpecialFoldersList := nil;
end;
 
 
function GetFolderType(FolderClass: string; ID: TBytes): TMAPIFldType;
var
  iCount: Integer;
begin
  Result := oFolderUndefined;
  for iCount := 0 to Length(SpecialFoldersList) - 1 do
    if IsSameTBytes(ID, SpecialFoldersList[iCount].EntryID) then
    begin
      Result := SpecialFoldersList[iCount].FolderType;
      Exit;
    end;
 
  if Result = oFolderUndefined then
    Result := GetMAPIFolderKnowType(FolderClass);
end;
 
 
procedure ClearHead(Node: TTreeNode);
var
  pDataS: PStoreHead;
  pDataF: PFolderHead;
begin
  if Assigned(Node.Data) then
  begin
    if Node.Level = 0 then
    begin
      pDataS := PStoreHead(Node.Data);
      pDataS.ID := nil;
    end
    else
    begin
      pDataF := PFolderHead(Node.Data);
      pDataF.ID := nil;
      pDataF.ParentID := nil;
      pDataF.StoreID := nil;
    end;
 
    Dispose(Node.Data);
  end;
  Node.Data := nil;
end;
 
 
function CopyStoreHead(TreeView: TTreeView; Row: TMAPITableFields): TTreeNode;
var
  StoreHead: PStoreHead;
  len: Integer;
begin
  (*
   Default columns are:
   PR_ENTRYID, PR_DISPLAY_NAME, PR_PROVIDER_DISPLAY, PR_DEFAULT_STORE, PR_MDB_PROVIDER
   *)
  New(StoreHead);
  len := Length(Row.ItemOf[PR_ENTRYID].AsBytes);
  SetLength(StoreHead.ID, len);
  Move(Row.ItemOf[PR_ENTRYID].AsBytes[0], StoreHead.ID[0], len);
  StoreHead.DisplayName := Row.ItemOf[PR_DISPLAY_NAME].AsString;
  StoreHead.ProviderDisplayName := Row.ItemOf[PR_PROVIDER_DISPLAY].AsString;
  StoreHead.IsDefault := Row.ItemOf[PR_DEFAULT_STORE].AsBoolean;
  StoreHead.StoreType := GetMsgStoreType(Row.ItemOf[PR_MDB_PROVIDER].AsBytes);
 
  if StoreHead^.IsDefault then
    Result := TreeView.Items.AddObjectFirst(nil, StoreHead.DisplayName, StoreHead)
  else
    Result := TreeView.Items.AddObject(nil, StoreHead.DisplayName, StoreHead);
 
  // Image Index
  if StoreHead^.IsDefault then
    Result.ImageIndex := 0
  else
    Result.ImageIndex := 1;
 
  Result.SelectedIndex := Result.ImageIndex;
  Result.Expanded := False;
 
  // Add Dummy Node for [+] Icon
  TreeView.Items.AddChildObjectFirst(Result, '', nil);
end;
 
 
function CopyFolderHead(ParentNode: TTreeNode; Row: TMAPITableFields): TTreeNode;
var
  FolderHead: PFolderHead;
  len: Integer;
  TreeView: TTreeView;
begin
  Result := nil;
  (* Default columns here are:
    PR_ENTRYID, PR_LONGTERM_ENTRYID_FROM_TABLE, PR_DISPLAY_NAME, PR_CONTAINER_CLASS, PR_CONTENT_COUNT, PR_CONTENT_UNREAD,
    PR_SUBFOLDERS, PR_PARENT_ENTRYID, PR_STORE_ENTRYID, PR_MDB_PROVIDER, PR_ATTR_HIDDEN
    *)
 
  // We are not interested in hidden folders
  if Row.PropExistsEx(PR_ATTR_HIDDEN) and Row.ItemOf[PR_ATTR_HIDDEN].AsBoolean then
    Exit;
 
  New(FolderHead);
 
  if Row.PropExistsEx(PR_LONGTERM_ENTRYID_FROM_TABLE) then
  begin
    len := Length(Row.ItemOf[PR_LONGTERM_ENTRYID_FROM_TABLE].AsBytes);
    SetLength(FolderHead.ID, len);
    Move(Row.ItemOf[PR_LONGTERM_ENTRYID_FROM_TABLE].AsBytes[0], FolderHead.ID[0], len);
  end
  else
  begin
    len := Length(Row.ItemOf[PR_ENTRYID].AsBytes);
    SetLength(FolderHead.ID, len);
    Move(Row.ItemOf[PR_ENTRYID].AsBytes[0], FolderHead.ID[0], len);
  end;
 
  if not Row.ItemOf[PR_DISPLAY_NAME].IsError then
    FolderHead.DisplayName := Row.ItemOf[PR_DISPLAY_NAME].AsString;
 
  if not Row.ItemOf[PR_CONTAINER_CLASS].IsError then
    FolderHead.FolderClass := Row.ItemOf[PR_CONTAINER_CLASS].AsString;
 
  FolderHead.FolderType := GetFolderType(FolderHead.FolderClass, FolderHead.ID);
 
  if not Row.ItemOf[PR_CONTENT_COUNT].IsError then
    FolderHead.MsgCount := Row.ItemOf[PR_CONTENT_COUNT].AsInteger;
 
  if not Row.ItemOf[PR_CONTENT_UNREAD].IsError then
    FolderHead.UnReadMsgCount := Row.ItemOf[PR_CONTENT_UNREAD].AsInteger;
 
  if not Row.ItemOf[PR_SUBFOLDERS].IsError then
    FolderHead.HasSubFolders := Row.ItemOf[PR_SUBFOLDERS].AsBoolean;
 
  if not Row.ItemOf[PR_PARENT_ENTRYID].IsError then
  begin
    len := Length(Row.ItemOf[PR_PARENT_ENTRYID].AsBytes);
    SetLength(FolderHead.ParentID, len);
    Move(Row.ItemOf[PR_PARENT_ENTRYID].AsBytes[0], FolderHead.ParentID[0], len);
  end;
 
  if not Row.ItemOf[PR_STORE_ENTRYID].IsError then
  begin
    len := Length(Row.ItemOf[PR_STORE_ENTRYID].AsBytes);
    SetLength(FolderHead.StoreID, len);
    Move(Row.ItemOf[PR_STORE_ENTRYID].AsBytes[0], FolderHead.StoreID[0], len);
  end;
 
  FolderHead.StoreType := GetMsgStoreType(Row.ItemOf[PR_MDB_PROVIDER].AsBytes);
 
  TreeView := TTreeView(ParentNode.TreeView);
 
  Result := TreeView.Items.AddChildObject(ParentNode, FolderHead^.DisplayName, FolderHead);
 
  Result.ImageIndex := GetFldIconIndex(FolderHead.FolderType);
  Result.SelectedIndex := Result.ImageIndex;
 
  // Add Dummy Node for [+] Icon
  if FolderHead.HasSubFolders then
    TreeView.Items.AddChildObject(Result, '', nil);
 
end;
 
 
procedure DeleteChild(Node: TTreeNode);
var
  TreeNode: TTreeNode;
begin
 
  TreeNode := Node.getFirstChild;
  while Assigned(TreeNode) do
  begin
    // Set Children MAPI Object to Not Active State
    if Assigned(TreeNode.Data) then
    begin
      ClearHead(TreeNode);
      TreeNode.Data := nil;
    end;
    if TreeNode.HasChildren then
      DeleteChild(TreeNode);
    TreeNode.DeleteChildren;
    TreeNode := Node.GetNextChild(TreeNode);
  end;
  Node.DeleteChildren;
end;
 
 
procedure TfrmMain.ClearMAPIObjects;
begin
  if Assigned(MessagesTable) then
    FreeAndNil(MessagesTable);
 
  DATAFolder := nil;
  ClearSpecialFoldersList;
 
  if Assigned(MAPIStore) then
    ReleaseMsgStore(MAPIStore);
  MAPIStore := nil;
  if Assigned(MAPISession) then
    ReleaseMapiSession(MAPISession);
  MAPISession := nil;
end;
 
 
procedure TfrmMain.btFastMdgFilterClick(Sender: TObject);
var
  DefSubText: string;
  PropTag: ULONG;
begin
  if not Assigned(MessagesTable) or (MessagesTable.Count < 1) then
    Exit;
 
  PropTag := 0;
 
  if Assigned(MessageListView.Selected) then
    DefSubText := MessageListView.Selected.SubItems[2]
  else
    DefSubText := '';
 
  if not InputQuery('Fast Msg Filter', 'Show only Messages where Subject Like', DefSubText) then
    Exit;
  if (DefSubText <> '') then
  begin
    PropTag := PR_SUBJECT;
  end;
 
  MessageListView.Items.BeginUpdate;
  try
    MessagesTable.FastFilter(PropTag, rLike, DefSubText);
 
  finally
    MessageListView.Items.Count := MessagesTable.Count;
    StatusBar.Panels[0].Text := IntToStr(MessageListView.Items.Count) + ' Items';
    if MessagesTable.IsFiltered then
      StatusBar.Panels[0].Text := StatusBar.Panels[0].Text + ' - Filter is applied!';
    MessageListView.Items.EndUpdate;
    MessageListView.ItemIndex := -1;
    MessageListView.Refresh;
  end;
end;
 
 
procedure TfrmMain.btLogOffClick(Sender: TObject);
begin
  // Release all MAPI Interfaces and Delphi objects
  ClearMAPIObjects;
  btLogOn.Enabled := True;
  btLogOff.Enabled := False;
end;
 
 
procedure TfrmMain.btLogOnClick(Sender: TObject);
begin
  // Get MAPI Session
  case rgProfile.ItemIndex of
    0:
      MAPISession := GetMAPISession(Self.Handle);
    1:
      MAPISession := GetMAPISession(Self.Handle, '', MAPI_LOGON_UI);
  end;
 
  if Assigned(MAPISession) then
  begin
    btLogOn.Enabled := False;
    btLogOff.Enabled := True;
    BuildFolderTree;
  end;
end;
 
 
procedure TfrmMain.BuildFolderTree;
var
  MAPITable: IMAPITable;
  iCount: Integer;
begin
  if not Assigned(MAPISession) then
    Exit;
 
  MAPITable := GetMAPIStoresTable(MAPISession);
  {
   GetMAPIStoresTable returns message store table that contains information about all the message stores in the session profile
   Default columns are:
   PR_ENTRYID, PR_DISPLAY_NAME, PR_PROVIDER_DISPLAY, PR_DEFAULT_STORE, PR_MDB_PROVIDER
   }
 
  with TMAPITable.Create(MAPITable) do
  begin
    for iCount := 0 to Count - 1 do
      CopyStoreHead(MailboxTreeView, Row[iCount]);
    Free;
  end;
end;
 
 
procedure TfrmMain.FormClose(Sender: TObject; var Action: TCloseAction);
begin
  // Release all MAPI Interfaces and Delphi objects
  ClearMAPIObjects;
  // UnInitialize MAPI Subsystem
  MapiUnInitialize;
end;
 
 
procedure TfrmMain.FormCreate(Sender: TObject);
begin
{$IF DEFINED (WIN64)}
  Self.Caption := Self.Caption + ' - WIN64';
{$ELSE}
  Self.Caption := Self.Caption + ' - WIN32';
{$IFEND}
  DATAFolder := nil;
  MAPIStore := nil;
  MAPISession := nil;
  hr := MapiInitialize(nil);
  if failed(hr) then
    raise EMAPIError.CreateMAPI(nil, hr);
 
  MessageListView.Items.Count := 0;
  // set Property_Tag for Columns sort
  MessageListView.Columns.Items[0].Tag := PR_ICON_INDEX;
  MessageListView.Columns.Items[1].Tag := PR_HASATTACH;
  MessageListView.Columns.Items[2].Tag := PR_SENDER_NAME;
  MessageListView.Columns.Items[3].Tag := PR_NORMALIZED_SUBJECT;
  MessageListView.Columns.Items[4].Tag := PR_CLIENT_SUBMIT_TIME;
  MessageListView.Columns.Items[5].Tag := PR_MESSAGE_SIZE;
end;
 
 
 
procedure TfrmMain.MailboxTreeViewChange(Sender: TObject; Node: TTreeNode);
var
  Cursor: TCursor;
begin
 
  Cursor := Screen.Cursor;
  Screen.Cursor := crHourGlass;
 
  try
    if Node.Level > 0 then
    begin
      CheckStore(PFolderHead(Node.Data)^.StoreID);
      GetMessages(Node.Data);
    end
    else
    begin
      btFastMdgFilter.Enabled := False;
      MessageListView.Items.Count := 0;
      MessageListView.Refresh;
      CheckStore(PStoreHead(Node.Data)^.ID);
    end;
 
  finally
    Screen.Cursor := Cursor;
  end;
 
  if Node.Level = 0 then
    StatusBar.Panels[0].Text := PStoreHead(Node.Data).DisplayName;
 
end;
 
procedure TfrmMain.MailboxTreeViewCollapsing(Sender: TObject; Node: TTreeNode; var AllowCollapse: Boolean);
begin
  CollapseLevel(Node);
end;
 
 
procedure TfrmMain.MailboxTreeViewExpanding(Sender: TObject; Node: TTreeNode; var AllowExpansion: Boolean);
var
  FirstChild: TTreeNode;
begin
  FirstChild := Node.getFirstChild;
  if Assigned(FirstChild) and (FirstChild.Data = nil) then
  begin
    Node.DeleteChildren;
    ExpandLevel(Node);
  end;
end;
 
 
procedure TfrmMain.MessageListViewColumnClick(Sender: TObject; Column: TListColumn);
var
  iCount: Integer;
begin
  if not Assigned(MessagesTable) then
    Exit;
 
  if (MessageListView.Items.Count = 0) or not Assigned(MailboxTreeView.Selected) or not Assigned(MailboxTreeView.Selected.Data) or
    (MailboxTreeView.Selected.Level = 0) then
    Exit;
 
  if ColumnIndex = Column.Index then
    SortAscending := not SortAscending
  else
  begin
    ColumnIndex := Column.Index;
    SortAscending := True;
    for iCount := 2 to MessageListView.Columns.Count - 1 do
      MessageListView.Columns.Items[iCount].ImageIndex := -1;
  end;
 
  if Column.Index > 1 then
    case SortAscending of
      True:
        Column.ImageIndex := 183;
      False:
        Column.ImageIndex := 184;
    end;
 
  ColumnTag := Column.Tag;
 
  MessagesTable.FastSort(ColumnTag, SortAscending);
  MessageListView.Refresh;
 
  SortAscendingOld := SortAscending;
  ColumnTagOld := ColumnTag;
 
end;
 
 
procedure TfrmMain.MessageListViewData(Sender: TObject; Item: TListItem);
var
  ItemIndex: Integer;
  IconIndex: Integer;
  MessageClass: string;
  MessageFlags: Integer;
begin
  ItemIndex := Item.Index;
  if ItemIndex > MessagesTable.Count - 1 then
    Exit;
 
  (*
   Default columns are:
   PR_ENTRYID, PR_LONGTERM_ENTRYID_FROM_TABLE, PR_MESSAGE_CLASS, PR_HASATTACH, PR_SUBJECT, PR_SENDER_NAME,
   PR_SENDER_EMAIL_ADDRESS, PR_CLIENT_SUBMIT_TIME, PR_MESSAGE_SIZE, PR_MESSAGE_FLAGS, PR_ICON_INDEX
   *)
 
  IconIndex := -1;
  MessageClass := '';
  MessageFlags := 0;
 
  if MessagesTable.Row[ItemIndex].PropExistsEx(PR_ICON_INDEX) then
    IconIndex := MessagesTable.Row[ItemIndex].ItemOf[PR_ICON_INDEX].AsInteger;
  if MessagesTable.Row[ItemIndex].PropExistsEx(PR_MESSAGE_CLASS) then
    MessageClass := MessagesTable.Row[ItemIndex].ItemOf[PR_MESSAGE_CLASS].AsString;
  if MessagesTable.Row[ItemIndex].PropExistsEx(PR_MESSAGE_FLAGS) then
    MessageFlags := MessagesTable.Row[ItemIndex].ItemOf[PR_MESSAGE_FLAGS].AsInteger;
  Item.ImageIndex := CalculateMsgIconIndex(IconIndex, MessageClass, MessageFlags);
 
  Item.SubItems.Add('');
  if MessagesTable.Row[ItemIndex].ItemOf[PR_HASATTACH].AsBoolean then
    Item.SubItemImages[0] := 187
  else
    Item.SubItemImages[0] := -1;
 
  if MessagesTable.Row[ItemIndex].PropExistsEx(PR_SENDER_NAME) then
    Item.SubItems.Add(MessagesTable.Row[ItemIndex].ItemOf[PR_SENDER_NAME].AsString)
  else
    Item.SubItems.Add('');
 
  Item.SubItems.Add(MessagesTable.Row[ItemIndex].ItemOf[PR_SUBJECT].AsString);
 
  if MessagesTable.Row[ItemIndex].PropExistsEx(PR_CLIENT_SUBMIT_TIME) then
    Item.SubItems.Add(DateTimeToStr(MessagesTable.Row[ItemIndex].ItemOf[PR_CLIENT_SUBMIT_TIME].AsDateTime))
  else
    Item.SubItems.Add('');
 
  Item.SubItems.Add(ShowCustomSize(MessagesTable.Row[ItemIndex].ItemOf[PR_MESSAGE_SIZE].AsInteger));
end;
 
 
procedure TfrmMain.MessageListViewDblClick(Sender: TObject);
var
  ItemIndex: Integer;
  MAPIMessage: IMessage;
  ID: TBytes;
begin
  ID := nil;
 
  if (MessageListView.Items.Count < 1) or not Assigned(MessagesTable) then
    Exit;
 
  ItemIndex := MessageListView.Selected.Index;
 
  if MessagesTable.Row[ItemIndex].PropExistsEx(PR_LONGTERM_ENTRYID_FROM_TABLE) then
    ID := MessagesTable.Row[ItemIndex].ItemOf[PR_LONGTERM_ENTRYID_FROM_TABLE].AsBytes
  else
    ID := MessagesTable.Row[ItemIndex].ItemOf[PR_ENTRYID].AsBytes;
 
  MAPIMessage := GetMapiMessage(MAPIStore, ID);
 
  with TfrmMessage.Create(Self) do
  begin
    SetMessage(MAPIMessage);
    ShowModal;
  end;
 
end;
 
 
procedure TfrmMain.ExpandLevel(Node: TTreeNode);
var
  iCount: Integer;
  isStore: Boolean;
  MAPITable: IMAPITable;
  MAPIFolder: IMAPIFolder;
begin
  isStore := (Node.Level = 0);
 
  if isStore then
    CheckStore(PStoreHead(Node.Data)^.ID);
 
  if not isStore then
    if Assigned(MAPIStore) and not IsSameMAPIObject(MAPISession, MAPIStore, PFolderHead(Node.Data)^.StoreID) then
    begin
      ReleaseMsgStore(MAPIStore);
      MAPIStore := GetMAPIStore(MAPISession, PFolderHead(Node.Data)^.StoreID);
    end;
 
  if isStore then
    MAPITable := GetMAPIFoldersTable(MAPIStore)
  else
  begin
    MAPIFolder := GetMAPIFolder(MAPIStore, PFolderHead(Node.Data)^.ID);
    MAPITable := GetMAPIFoldersTable(MAPIFolder);
  end;
 
  with TMAPITable.Create(MAPITable) do
  begin
    for iCount := 0 to Count - 1 do
      CopyFolderHead(Node, Row[iCount]);
    Free;
  end;
end;
 
 
procedure TfrmMain.CollapseLevel(Node: TTreeNode);
var
  TreeNode: TTreeNode;
  SelectedNode: TTreeNode;
  isStore: Boolean;
begin
  SelectedNode := MailboxTreeView.Selected;
  isStore := (Node.Level = 0);
 
  // Delete All Children
  if Node.HasChildren then
  begin
    TreeNode := Node.getFirstChild;
    while Assigned(TreeNode) do
    begin
      // Set Children MAPI Object to Not Active State
      if Assigned(TreeNode.Data) then
      begin
        ClearHead(TreeNode);
        TreeNode.Data := nil;
      end;
      if TreeNode.HasChildren then
        DeleteChild(TreeNode);
 
      TreeNode.DeleteChildren;
      TreeNode := Node.GetNextChild(TreeNode);
    end;
    Node.DeleteChildren;
  end;
 
  if Node.Selected and (Node <> SelectedNode) and (Node.Level > 0) then
  begin
    GetMessages(Node.Data)
  end;
 
  // Add Dummy Node for [+] Icon
  if isStore or PFolderHead(Node.Data)^.HasSubFolders then
    MailboxTreeView.Items.AddChildObjectFirst(Node, '', nil);
end;
 
 
procedure TfrmMain.CheckStore(StoreID: TBytes);
begin
  if Assigned(MAPIStore) and not IsSameMAPIObject(MAPISession, MAPIStore, StoreID) then
  begin
    ReleaseMsgStore(MAPIStore);
    MAPIStore := nil;
  end;
 
  if not Assigned(MAPIStore) then
  begin
    MAPIStore := GetMAPIStore(MAPISession, StoreID);
    ClearSpecialFoldersList;
    SpecialFoldersList := GetMAPISpecialFoldersIDList(MAPIStore);
  end;
end;
 
 
procedure TfrmMain.GetMessages(P: Pointer);
var
  FolderHead: PFolderHead;
  MAPITable: IMAPITable;
begin
  btFastMdgFilter.Enabled := False;
  if not Assigned(P) then
    Exit;
  FolderHead := PFolderHead(P);
 
  if not IsSameTBytes(FolderHead^.ID, FolderID) then
  begin
    if Assigned(MessagesTable) then
      FreeAndNil(MessagesTable);
    CheckStore(FolderHead^.StoreID);
    DATAFolder := GetMAPIFolder(MAPIStore, FolderHead^.ID);
    MAPITable := GetMsgTable(DATAFolder, ColumnTag, SortAscending);
    SetLength(FolderID, Length(FolderHead^.ID));
    Move(FolderHead^.ID[0], FolderID[0], Length(FolderHead^.ID));
    MessagesTable := TMAPITable.Create(MAPITable);
  end;
 
  // Force virtual ListView to render items
  if MessagesTable.Count <> MessageListView.Items.Count then
  begin
    MessageListView.Items.Count := MessagesTable.Count;
    MessageListView.Refresh;
  end;
 
  StatusBar.Panels[0].Text := 'Message Count: ' + IntToStr(MessagesTable.Count) + ' in ' + FolderHead^.DisplayName;
  Application.ProcessMessages;
 
  btFastMdgFilter.Enabled := MessagesTable.Count > 0;
end;
 
 
end.