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RnQ/for.RnQ/VTV/Source/VTAccessibility.pas

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unit VTAccessibility;
// This unit implements iAccessible interfaces for the VirtualTree visual components
// and the currently focused node.
//
// Written by Marco Zehe. (c) 2007
interface
uses
Winapi.Windows, System.Classes, Winapi.ActiveX, System.Types, Winapi.oleacc,
VirtualTrees, VTAccessibilityFactory, Vcl.Controls;
type
TVirtualTreeAccessibility = class(TInterfacedObject, IDispatch, IAccessible)
private
FVirtualTree: TVirtualStringTree;
public
constructor Create(AVirtualTree: TVirtualStringTree);
{ IAccessibility }
function Get_accParent(out ppdispParent: IDispatch): HResult; stdcall;
function Get_accChildCount(out pcountChildren: Integer): HResult; stdcall;
function Get_accChild(varChild: OleVariant; out ppdispChild: IDispatch): HResult; stdcall;
function Get_accName(varChild: OleVariant; out pszName: WideString): HResult; stdcall;
function Get_accValue(varChild: OleVariant; out pszValue: WideString): HResult; stdcall;
function Get_accDescription(varChild: OleVariant; out pszDescription: WideString): HResult; stdcall;
function Get_accRole(varChild: OleVariant; out pvarRole: OleVariant): HResult; stdcall;
function Get_accState(varChild: OleVariant; out pvarState: OleVariant): HResult; stdcall;
function Get_accHelp(varChild: OleVariant; out pszHelp: WideString): HResult; stdcall;
function Get_accHelpTopic(out pszHelpFile: WideString; varChild: OleVariant;
out pidTopic: Integer): HResult; stdcall;
function Get_accKeyboardShortcut(varChild: OleVariant; out pszKeyboardShortcut: WideString): HResult; stdcall;
function Get_accFocus(out pvarChild: OleVariant): HResult; stdcall;
function Get_accSelection(out pvarChildren: OleVariant): HResult; stdcall;
function Get_accDefaultAction(varChild: OleVariant; out pszDefaultAction: WideString): HResult; stdcall;
function accSelect(flagsSelect: Integer; varChild: OleVariant): HResult; stdcall;
function accLocation(out pxLeft: Integer; out pyTop: Integer; out pcxWidth: Integer;
out pcyHeight: Integer; varChild: OleVariant): HResult; stdcall;
function accNavigate(navDir: Integer; varStart: OleVariant; out pvarEndUpAt: OleVariant): HResult; stdcall;
function accHitTest(xLeft: Integer; yTop: Integer; out pvarChild: OleVariant): HResult; stdcall;
function accDoDefaultAction(varChild: OleVariant): HResult; stdcall;
function Set_accName(varChild: OleVariant; const pszName: WideString): HResult; stdcall;
function Set_accValue(varChild: OleVariant; const pszValue: WideString): HResult; stdcall;
{IDispatch}
function GetIDsOfNames(const IID: TGUID; Names: Pointer;
NameCount: Integer; LocaleID: Integer; DispIDs: Pointer): HRESULT; stdcall;
function GetTypeInfo(Index: Integer; LocaleID: Integer;
out TypeInfo): HRESULT; stdcall;
function GetTypeInfoCount(out Count: Integer): HRESULT; stdcall;
function Invoke(DispID: Integer; const IID: TGUID; LocaleID: Integer;
Flags: Word; var Params; VarResult: Pointer; ExcepInfo: Pointer;
ArgErr: Pointer): HRESULT; stdcall;
end;
TVirtualTreeItemAccessibility = class(TVirtualTreeAccessibility, IAccessible)
public
{ IAccessibility }
function Get_accParent(out ppdispParent: IDispatch): HResult; stdcall;
function Get_accChildCount(out pcountChildren: Integer): HResult; stdcall;
function Get_accChild(varChild: OleVariant; out ppdispChild: IDispatch): HResult; stdcall;
function Get_accName(varChild: OleVariant; out pszName: WideString): HResult; stdcall;
function Get_accValue(varChild: OleVariant; out pszValue: WideString): HResult; stdcall;
function Get_accDescription(varChild: OleVariant; out pszDescription: WideString): HResult; stdcall;
function Get_accRole(varChild: OleVariant; out pvarRole: OleVariant): HResult; stdcall;
function Get_accState(varChild: OleVariant; out pvarState: OleVariant): HResult; stdcall;
function accLocation(out pxLeft: Integer;
out pyTop: Integer; out pcxWidth: Integer;
out pcyHeight: Integer; varChild: OleVariant): HResult; stdcall;
function Get_accFocus(out pvarChild: OleVariant): HRESULT; stdcall;
end;
TVTMultiColumnItemAccessibility = class(TVirtualTreeItemAccessibility, IAccessible)
strict private
function GetItemDescription(varChild: OleVariant; out pszDescription: WideString; IncludeMainColumn: boolean): HResult; stdcall;
public
{ IAccessibility }
function Get_accName(varChild: OleVariant; out pszName: WideString): HResult; stdcall;
function Get_accDescription(varChild: OleVariant; out pszDescription: WideString): HResult; stdcall;
end;
TVTDefaultAccessibleProvider = class(TInterfacedObject, IVTAccessibleProvider)
public
function CreateIAccessible(ATree: TBaseVirtualTree): IAccessible;
end;
TVTDefaultAccessibleItemProvider = class(TInterfacedObject, IVTAccessibleProvider)
public
function CreateIAccessible(ATree: TBaseVirtualTree): IAccessible;
end;
TVTMultiColumnAccessibleItemProvider = class(TInterfacedObject, IVTAccessibleProvider)
public
function CreateIAccessible(ATree: TBaseVirtualTree): IAccessible;
end;
implementation
uses
System.SysUtils, Vcl.Forms, System.Variants, System.Math;
{ TVirtualTreeAccessibility }
//----------------------------------------------------------------------------------------------------------------------
constructor TVirtualTreeAccessibility.Create(AVirtualTree: TVirtualStringTree);
// assigns the parent and current fields, and lets the control's IAccessible object know its address.
begin
inherited Create;
FVirtualTree := AVirtualTree;
end;
//----------------------------------------------------------------------------------------------------------------------
function TVirtualTreeAccessibility.accDoDefaultAction(varChild: OleVariant): HResult;
// a default action is not supported.
begin
Result := DISP_E_MEMBERNOTFOUND;
end;
//----------------------------------------------------------------------------------------------------------------------
function TVirtualTreeAccessibility.accHitTest(xLeft: Integer; yTop: Integer; out pvarChild: OleVariant): HResult;
// returns the iAccessible object at the given point, if applicable.
var
Pt: TPoint;
HitInfo: THitInfo;
begin
Result := S_FALSE;
if FVirtualTree <> nil then
begin
// VariantInit(pvarChild);
// TVarData(pvarChild).VType := VT_I4;
Pt := fVirtualTree.ScreenToClient(Point(xLeft, yTop));
if fVirtualTree.FocusedNode <> nil then
begin
fVirtualTree.GetHitTestInfoAt(xLeft, yTop, false, HitInfo);
if FVirtualTree.FocusedNode = HitInfo.HitNode then
begin
pvarChild := FVirtualTree.AccessibleItem;
Result := S_OK;
exit;
end;
end;
if PtInRect(FVirtualTree.BoundsRect, Pt) then
begin
pvarChild := CHILDID_SELF;
Result := S_OK;
end;
end;
end;
//----------------------------------------------------------------------------------------------------------------------
function TVirtualTreeAccessibility.accLocation(out pxLeft: Integer;
out pyTop: Integer; out pcxWidth: Integer;
out pcyHeight: Integer; varChild: OleVariant): HResult;
// returns the location of the VirtualStringTree object.
var
P: TPoint;
begin
Result := S_FALSE;
if varChild = CHILDID_SELF then
begin
if FVirtualTree <> nil then
begin
P := FVirtualTree.ClientToScreen(FVirtualTree.ClientRect.TopLeft);
pxLeft := P.X;
pyTop := P.Y;
pcxWidth := FVirtualTree.Width;
pcyHeight := FVirtualTree.Height;
Result := S_OK;
end;
end
else if VarType(varchild) = VT_I4 then
begin
// return the location of the focused node
if (FVirtualTree <> nil) and (FVirtualTree.AccessibleItem <> nil) then
begin
Result := FVirtualTree.AccessibleItem.accLocation(pxLeft, pyTop, pcxWidth, pcyHeight, CHILDID_SELF);
end;
end;
end;
//----------------------------------------------------------------------------------------------------------------------
function TVirtualTreeAccessibility.accNavigate(navDir: Integer; varStart: OleVariant;
out pvarEndUpAt: OleVariant): HResult;
// This is not supported.
begin
Result := DISP_E_MEMBERNOTFOUND;
end;
//----------------------------------------------------------------------------------------------------------------------
function TVirtualTreeAccessibility.Get_accSelection(out pvarChildren: OleVariant): HResult;
// returns the selected child ID, if any.
begin
Result := s_false;
if FVirtualTree <> nil then
if fVirtualTree.FocusedNode <> nil then
begin
pvarChildren := 1;
result := s_OK;
end;
end;
//----------------------------------------------------------------------------------------------------------------------
function TVirtualTreeAccessibility.GetIDsOfNames(const IID: TGUID;
Names: Pointer; NameCount, LocaleID: Integer; DispIDs: Pointer): HRESULT;
// Not supported.
begin
Result := E_NOTIMPL;
end;
//----------------------------------------------------------------------------------------------------------------------
function TVirtualTreeAccessibility.GetTypeInfo(Index, LocaleID: Integer;
out TypeInfo): HRESULT;
// not supported.
begin
Result := E_NOTIMPL;
end;
//----------------------------------------------------------------------------------------------------------------------
function TVirtualTreeAccessibility.GetTypeInfoCount(
out Count: Integer): HRESULT;
// not supported.
begin
Result := E_NOTIMPL;
end;
//----------------------------------------------------------------------------------------------------------------------
function TVirtualTreeAccessibility.Get_accChild(varChild: OleVariant; out ppdispChild: IDispatch): HResult;
// returns the iAccessible child, whicfh represents the focused item.
begin
if varChild = CHILDID_SELF then
begin
ppdispChild := FVirtualTree.AccessibleItem;
Result := S_OK;
end
else
Result := E_INVALIDARG
end;
//----------------------------------------------------------------------------------------------------------------------
function TVirtualTreeAccessibility.Get_accChildCount(out pcountChildren: Integer): HResult;
// Returns the number 1 for the one child: The focused item.
begin
pcountChildren := 1;
Result := S_OK;
end;
//----------------------------------------------------------------------------------------------------------------------
function TVirtualTreeAccessibility.Get_accDefaultAction(varChild: OleVariant; out pszDefaultAction: WideString): HResult;
// Not supported.
begin
Result := DISP_E_MEMBERNOTFOUND;
end;
//----------------------------------------------------------------------------------------------------------------------
function TVirtualTreeAccessibility.Get_accDescription(varChild: OleVariant; out pszDescription: WideString): HResult;
// returns the hint of the control, if assigned.
begin
pszDescription := '';
Result := S_FALSE;
if varChild = CHILDID_SELF then
begin
if FVirtualTree <> nil then
pszDescription := GetLongHint(fVirtualTree.Hint);
end;
if Length(pszDescription) > 0 then
Result := S_OK;
end;
//----------------------------------------------------------------------------------------------------------------------
function TVirtualTreeAccessibility.Get_accFocus(out pvarChild: OleVariant): HResult;
// returns the child ID of 1, if assigned.
begin
Result := s_false;
if fVirtualTree <> nil then
begin
if FVirtualTree.FocusedNode <> nil then
pvarChild := FVirtualTree.AccessibleItem
else
pvarChild := childid_self;
result := S_OK;
end;
end;
//----------------------------------------------------------------------------------------------------------------------
function TVirtualTreeAccessibility.Get_accHelp(varChild: OleVariant; out pszHelp: WideString): HResult;
// Not supported.
begin
Result := DISP_E_MEMBERNOTFOUND;
end;
//----------------------------------------------------------------------------------------------------------------------
function TVirtualTreeAccessibility.Get_accHelpTopic(out pszHelpFile: WideString; varChild: OleVariant;
out pidTopic: Integer): HResult;
// Returns the HelpContext ID, if present.
begin
pszHelpFile := '';
pidTopic := 0;
Result := S_OK;
if varChild = CHILDID_SELF then
if FVirtualTree <> nil then
begin
pszHelpFile := Application.HelpFile;
pidTopic := FVirtualTree.HelpContext;
end;
end;
//----------------------------------------------------------------------------------------------------------------------
function TVirtualTreeAccessibility.Get_accKeyboardShortcut(varChild: OleVariant; out pszKeyboardShortcut: WideString): HResult;
// Not supported.
begin
pszKeyboardShortcut := '';
Result := S_FALSE;
end;
//----------------------------------------------------------------------------------------------------------------------
function TVirtualTreeAccessibility.Get_accName(varChild: OleVariant; out pszName: WideString): HResult;
// if set, returns the new published AccessibleName property.
// if not set, tries the name and class name properties.
// otherwise, returns the default text.
begin
pszName := '';
Result := S_FALSE;
if varChild = CHILDID_SELF then
begin
if FVirtualTree <> nil then
begin
if FVirtualTree.AccessibleName <> '' then
pszName := FVirtualTree.AccessibleName
else if FVirtualTree.Name <> '' then
pszName := FVirtualTree.Name
else if FVirtualTree.ClassName <> '' then
pszName := FVirtualTree.ClassName
else
PSZName := FVirtualTree.DefaultText;
result := S_OK;
end;
end
else if varType(varChild) = VT_I4 then
begin
// return the name for the inner accessible item
if (FVirtualTree <> nil) and (FVirtualTree.AccessibleItem <> nil) then
begin
Result := FVirtualTree.AccessibleItem.Get_accName(CHILDID_SELF, pszName);
end;
end;
end;
//----------------------------------------------------------------------------------------------------------------------
function TVirtualTreeAccessibility.Get_accParent(out ppdispParent: IDispatch): HResult;
// Returns false, the tree itself does not have a parent.
var
hParent: HWND;
begin
Result := E_INVALIDARG;
ppdispParent := nil;
// Addition - Simon Moscrop 7/5/2009
if (FVirtualTree.HandleAllocated) then
begin
(* return the accesible object from the 'parent' which is the window of the
tree itself! (This doesn't initially appear correct but it seems to
be exactly what all the other controls do! To verfify try pointing the
ms accessibility explorer at a simple button control which has been dropped
onto a form.
*)
hParent := FVirtualTree.Handle;
RESULT := AccessibleObjectFromWindow(hParent,CHILDID_SELF,IID_IAccessible,pointeR(ppDispParent));
end;
end;
//----------------------------------------------------------------------------------------------------------------------
function TVirtualTreeAccessibility.Get_accRole(varChild: OleVariant; out pvarRole: OleVariant): HResult;
// tells MSAA that it is a TreeView.
begin
Result := S_OK;
// VariantInit(pvarRole);
// TVarData(pvarRole).VType := VT_I4;
if varChild = CHILDID_SELF then
begin
if FVirtualTree <> nil then
pvarRole := ROLE_SYSTEM_OUTLINE;
end
else if VarType(varChild) = VT_I4 then
begin
// return the role of the inner accessible object
if (FVirtualTree <> nil) and (FVirtualTree.FocusedNode <> nil) then
pvarRole := ROLE_SYSTEM_OUTLINEITEM
else
RESULT := S_FALSE;
end;
end;
//----------------------------------------------------------------------------------------------------------------------
function TVirtualTreeAccessibility.accSelect(flagsSelect: Integer; varChild: OleVariant): HResult;
var
lIndexToSelect: Cardinal;
i: Integer;
lNode: PVirtualNode;
begin
lIndexToSelect := varChild;
if lIndexToSelect >= Self.FVirtualTree.TotalCount then
Exit(E_INVALIDARG);
lNode := FVirtualTree.GetFirst();
for i := 0 to Integer(lIndexToSelect) - 1 do
lNode := FVirtualTree.GetNext(lNode);
Result := E_NOTIMPL;
if (flagsSelect and SELFLAG_TAKEFOCUS) <> 0then begin
FVirtualTree.FocusedNode := lNode;
Result := S_OK;
end;//if SELFLAG_TAKEFOCUS
if (flagsSelect and SELFLAG_TAKESELECTION) <> 0 then begin
FVirtualTree.ClearSelection();
FVirtualTree.Selected[lNode] := True;
Result := S_OK;
end;//if SELFLAG_TAKEFOCUS
if (flagsSelect and SELFLAG_ADDSELECTION) <> 0 then begin
FVirtualTree.Selected[lNode] := True;
Result := S_OK;
end;
if (flagsSelect and SELFLAG_REMOVESELECTION) <> 0 then begin
FVirtualTree.Selected[lNode] := False;
Result := S_OK;
end;
end;
//----------------------------------------------------------------------------------------------------------------------
function TVirtualTreeAccessibility.Get_accState(varChild: OleVariant; out pvarState: OleVariant): HResult;
// returns the state of the control.
const
IsEnabled: array[Boolean] of Integer = (STATE_SYSTEM_UNAVAILABLE, 0);
HasPopup: array[Boolean] of Integer = (0, STATE_SYSTEM_HASPOPUP);
IsVisible: array[Boolean] of Integer = (STATE_SYSTEM_INVISIBLE, 0);
begin
Result := S_OK;
// VariantInit(pvarState);
// TVarData(pvarState).VType := VT_I4;
if varChild = CHILDID_SELF then
begin
if FVirtualTree <> nil then
begin
pvarState := STATE_SYSTEM_FOCUSED or STATE_SYSTEM_FOCUSABLE or STATE_SYSTEM_HOTTRACKED;
pvarState := pvarState or IsVisible[FVirtualTree.Visible];
pvarState := pvarState or IsEnabled[FVirtualTree.Enabled];
end
else
Result := E_INVALIDARG;
end
else if VarType(VarChild) = VT_I4 then
begin
// return the state of the inner accessible item
if (FVirtualTree <> nil) and (FVirtualTree.AccessibleItem <> nil) then
begin
Result := FVirtualTree.AccessibleItem.Get_accState(CHILDID_SELF, pVarState);
end
else
RESULT := E_INVALIDARG;
end;
end;
//----------------------------------------------------------------------------------------------------------------------
function TVirtualTreeAccessibility.Get_accValue(varChild: OleVariant; out pszValue: WideString): HResult;
// the TreeView control itself does not have a value, returning false here.
begin
RESULT := S_FALSE;
pszValue := '';
if VarType(varChild) = VT_I4 then
if varChild = CHILDID_SELF then
Result := S_FALSE
else if (FVirtualTree <> nil) and (FVirtualTree.AccessibleItem <> nil) then
RESULT := FVirtualTree.AccessibleItem.Get_accValue(CHILDID_SELF,pszValue);
end;
//----------------------------------------------------------------------------------------------------------------------
function TVirtualTreeAccessibility.Invoke(DispID: Integer; const IID: TGUID;
LocaleID: Integer; Flags: Word; var Params; VarResult, ExcepInfo,
ArgErr: Pointer): HRESULT;
// not supported.
begin
Result := E_NOTIMPL;
end;
//----------------------------------------------------------------------------------------------------------------------
function TVirtualTreeAccessibility.Set_accName(varChild: OleVariant; const pszName: WideString): HResult; stdcall;
// not supported.
begin
Result := DISP_E_MEMBERNOTFOUND;
end;
//----------------------------------------------------------------------------------------------------------------------
function TVirtualTreeAccessibility.Set_accValue(varChild: OleVariant; const pszValue: WideString): HResult;
// not supported.
begin
Result := DISP_E_MEMBERNOTFOUND
end;
{ TVirtualTreeItemAccessibility }
//----------------------------------------------------------------------------------------------------------------------
function TVirtualTreeItemAccessibility.accLocation(out pxLeft, pyTop, pcxWidth,
pcyHeight: Integer; varChild: OleVariant): HResult;
// returns the location of the current accessible item.
var
P: TPoint;
DisplayRect: TRect;
begin
Result := S_FALSE;
if varChild = CHILDID_SELF then
begin
if FVirtualTree.FocusedNode <> nil then
begin
DisplayRect := FVirtualTree.GetDisplayRect(FVirtualTree.FocusedNode, FVirtualTree.Header.Columns.GetFirstVisibleColumn, True, False);//Use first visible column instead of -1
P := FVirtualTree.ClientToScreen(DisplayRect.TopLeft);
pxLeft := P.X;
pyTop := P.Y;
pcxWidth := DisplayRect.Right - DisplayRect.Left;
pcyHeight := DisplayRect.Bottom - DisplayRect.Top;
Result := S_OK;
end;
end;
end;
//----------------------------------------------------------------------------------------------------------------------
function TVirtualTreeItemAccessibility.Get_accChild(varChild: OleVariant; out ppdispChild: IDispatch): HResult;
// the item does not have children. Returning false.
begin
ppdispChild := nil;
Result := S_FALSE;
end;
//----------------------------------------------------------------------------------------------------------------------
function TVirtualTreeItemAccessibility.Get_accChildCount(out pcountChildren: Integer): HResult;
// the item itself does not have children, returning 0.
begin
pcountChildren := 0;
Result := S_OK;
end;
//----------------------------------------------------------------------------------------------------------------------
function TVirtualTreeItemAccessibility.Get_accDescription(varChild: OleVariant; out pszDescription: WideString): HResult;
// not supported for an item.
begin
Result := DISP_E_MEMBERNOTFOUND;
end;
//----------------------------------------------------------------------------------------------------------------------
function TVirtualTreeItemAccessibility.Get_accFocus(out pvarChild: OleVariant): HResult;
begin
// must override this or we get an infinite loop when using MS narrator
// when navigating using the arrow keys.
RESULT := S_FALSE;
if FVirtualTree.FocusedNode <> nil then
begin
pvarChild := CHILDID_SELF;
RESULT := S_OK;
end;
end;
function TVirtualTreeItemAccessibility.Get_accName(varChild: OleVariant; out pszName: WideString): HResult;
// the name is the node's caption.
var
kind: TVTImageKind;
ImgText: WideString;
begin
pszName := '';
Result := S_FALSE;
if varChild = childid_self then
begin
if FVirtualTree <> nil then
if FVirtualTree.FocusedNode <> nil then
begin
for kind := ikNormal to ikOverlay do
begin
ImgText := FVirtualTree.ImageText[FVirtualTree.FocusedNode, Kind, FVirtualTree.Header.MainColumn];
if ImgText <> '' then
pszName := pszName + ImgText + ' ';
end;
pszName := pszName + FVirtualTree.Text[FVirtualTree.FocusedNode, FVirtualTree.Header.MainColumn];
result := S_OK;
end
else begin
PSZName := FVirtualTree.DefaultText;
result := S_OK;
end;
end;
end;
//----------------------------------------------------------------------------------------------------------------------
function TVirtualTreeItemAccessibility.Get_accParent(out ppdispParent: IDispatch): HResult;
// tells MSAA that the VritualStringTree is its parent.
begin
result := S_FALSE;
if FVirtualTree <> nil then
begin
ppdispParent := FVirtualTree.Accessible;
Result := S_OK;
end;
end;
//----------------------------------------------------------------------------------------------------------------------
function TVirtualTreeItemAccessibility.Get_accRole(varChild: OleVariant; out pvarRole: OleVariant): HResult;
// tells MSAA that it is a TreeView item as opposed to the TreeView itself.
begin
Result := S_OK;
// VariantInit(pvarRole);
// TVarData(pvarRole).VType := VT_I4;
if varChild = childid_self then
begin
if FVirtualTree <> nil then
pvarRole := ROLE_SYSTEM_OUTLINEITEM;
end;
end;
//----------------------------------------------------------------------------------------------------------------------
function TVirtualTreeItemAccessibility.Get_accState(varChild: OleVariant; out pvarState: OleVariant): HResult;
// Tells MSAA the state the item is in.
const
IsEnabled: array[Boolean] of Integer = (STATE_SYSTEM_UNAVAILABLE, 0);
HasPopup: array[Boolean] of Integer = (0, STATE_SYSTEM_HASPOPUP);
IsVisible: array[Boolean] of Integer = (STATE_SYSTEM_INVISIBLE, 0);
IsChecked: array[Boolean] of Integer = (0, STATE_SYSTEM_CHECKED);
IsExpanded: array[Boolean] of Integer = (0, STATE_SYSTEM_EXPANDED);
IsCollapsed: array[Boolean] of Integer = (0, STATE_SYSTEM_COLLAPSED);
begin
Result := S_OK;
// VariantInit(pvarState);
// TVarData(pvarState).VType := VT_I4;
if varChild = childid_self then
begin
if FVirtualTree <> nil then
begin
pvarState := STATE_SYSTEM_FOCUSED or STATE_SYSTEM_FOCUSABLE or STATE_SYSTEM_HOTTRACKED;
pvarState := pvarState or IsVisible[FVirtualTree.Visible];
pvarState := pvarState or IsEnabled[FVirtualTree.Enabled];
if fVirtualTree.FocusedNode <> nil then
begin
pvarState := pvarState or IsChecked[csCheckedNormal = FVirtualTree.FocusedNode.CheckState];
pvarState := pvarState or IsExpanded[VSExpanded in FVirtualTree.FocusedNode.States];
if not (vsExpanded in FVirtualTree.FocusedNode.States) then
pvarState:= PvarState or IsCollapsed[vsHasChildren in FVirtualTree.FocusedNode.States];
end;
end
else
Result := E_INVALIDARG;
end;
end;
//----------------------------------------------------------------------------------------------------------------------
function TVirtualTreeItemAccessibility.Get_accValue(varChild: OleVariant; out pszValue: WideString): HResult;
// for a TreeView item, the value is the nesting level number, 0-based.
begin
pszValue := '';
Result := S_FALSE;
if varChild = childid_self then
if FVirtualTree <> nil then
if FVirtualTree.FocusedNode <> nil then
begin
PSZValue := IntToStr(FVirtualTree.GetNodeLevel(FVirtualTree.FocusedNode));
result := S_OK;
end;
end;
{ TVTMultiColumnItemAccessibility }
function TVTMultiColumnItemAccessibility.GetItemDescription(
varChild: OleVariant; out pszDescription: WideString;
IncludeMainColumn: boolean): HResult;
var
I: Integer;
ImgText: WideString;
kind: TVTImageKind;
begin
pszDescription := '';
Result := S_FALSE;
if varChild = childid_self then
begin
if FVirtualTree <> nil then
if FVirtualTree.FocusedNode <> nil then
begin
if IncludeMainColumn then
begin
for kind := ikNormal to ikOverlay do
begin
ImgText := FVirtualTree.ImageText[FVirtualTree.FocusedNode, Kind, FVirtualTree.Header.MainColumn];
if ImgText <> '' then
ImgText := ImgText + ' ';
end;
pszDescription := ImgText + FVirtualTree.Text[FVirtualTree.FocusedNode, FVirtualTree.Header.MainColumn] + '; ';
end;
for I := 0 to FVirtualTree.Header.Columns.Count - 1 do
if (FVirtualTree.Header.MainColumn <> I) and (coVisible in FVirtualTree.Header.Columns[I].Options) then
begin
for kind := ikNormal to ikOverlay do
begin
ImgText := FVirtualTree.ImageText[FVirtualTree.FocusedNode, Kind, I];
if ImgText <> '' then
ImgText := ImgText + ' ';
end;
ImgText := ImgText + FVirtualTree.Text[FVirtualTree.FocusedNode, I];
if ImgText <> '' then
pszDescription := pszDescription
+FVirtualTree.Header.Columns[I].Text
+': '
+ ImgText
+'; ';
end;
if pszDescription <> '' then
if pszDescription[Length(pszDescription)-1] = ';' then
Delete(pszDescription, length(pszDescription)-1, 2);
result := S_OK;
end
else begin
PSZDescription := FVirtualTree.DefaultText;
result := S_OK;
end;
end;
end;
function TVTMultiColumnItemAccessibility.Get_accDescription(
varChild: OleVariant; out pszDescription: WideString): HResult;
begin
result := GetItemDescription(varChild, pszDescription, false)
end;
function TVTMultiColumnItemAccessibility.Get_accName(varChild: OleVariant;
out pszName: WideString): HResult;
begin
result := GetItemDescription(varChild, pszName, true)
end;
{ TVTDefaultAccessibleProvider }
function TVTDefaultAccessibleProvider.CreateIAccessible(ATree: TBaseVirtualTree): IAccessible;
begin
result := TVirtualTreeAccessibility.Create(TVirtualStringTree(ATree));
end;
{ TVTDefaultAccessibleItemProvider }
function TVTDefaultAccessibleItemProvider.CreateIAccessible(ATree: TBaseVirtualTree): IAccessible;
begin
result := TVirtualTreeItemAccessibility.Create(TVirtualStringTree(ATree));
end;
{ TVTMultiColumnAccessibleItemProvider }
function TVTMultiColumnAccessibleItemProvider.CreateIAccessible(ATree: TBaseVirtualTree): IAccessible;
begin
result := nil;
if TVirtualStringTree(ATree).Header.UseColumns then
result := TVTMultiColumnItemAccessibility.Create(TVirtualStringTree(ATree));
end;
var
DefaultAccessibleProvider: TVTDefaultAccessibleProvider;
DefaultAccessibleItemProvider: TVTDefaultAccessibleItemProvider;
MultiColumnAccessibleProvider: TVTMultiColumnAccessibleItemProvider;
initialization
if DefaultAccessibleProvider = nil then
begin
DefaultAccessibleProvider := TVTDefaultAccessibleProvider.Create;
TVTAccessibilityFactory.GetAccessibilityFactory.RegisterAccessibleProvider(DefaultAccessibleProvider);
end;
if DefaultAccessibleItemProvider = nil then
begin
DefaultAccessibleItemProvider := TVTDefaultAccessibleItemProvider.Create;
TVTAccessibilityFactory.GetAccessibilityFactory.RegisterAccessibleProvider(DefaultAccessibleItemProvider);
end;
if MultiColumnAccessibleProvider = nil then
begin
MultiColumnAccessibleProvider := TVTMultiColumnAccessibleItemProvider.Create;
TVTAccessibilityFactory.GetAccessibilityFactory.RegisterAccessibleProvider(MultiColumnAccessibleProvider);
end;
finalization
TVTAccessibilityFactory.GetAccessibilityFactory.UnRegisterAccessibleProvider(MultiColumnAccessibleProvider);
MultiColumnAccessibleProvider := nil;
TVTAccessibilityFactory.GetAccessibilityFactory.UnRegisterAccessibleProvider(DefaultAccessibleItemProvider);
DefaultAccessibleItemProvider := nil;
TVTAccessibilityFactory.GetAccessibilityFactory.UnRegisterAccessibleProvider(DefaultAccessibleProvider);
DefaultAccessibleProvider := nil;
end.