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<hr><p align="left"><small>发信人: redforks (Forks), 信区: Delphi <br>
标 题: Dephi Bug - Action与Hint(2 Bug) <br>
发信站: BBS 水木清华站 (Fri Nov 27 21:41:38 1998) WWW-POST <br>
<br>
1. 若在Action的Hint属性及OnHint方法中若指定Long Hint(一般显示在状态行中长提示 <br>
信息,比如：'打开|打开一个已经存在的文件'，长短提示是用'|'隔开的）。这时若将这 <br>
个Action赋给一个Control（比如Button），当鼠标在这个Control上停留一会，应该显 <br>
示短提示时，却把整个提示字符串都显示出来了。 分析Delphi Hint 系统的源码得 <br>
知Delphi的Hint系统有两部分，一部分处理鼠标的短提示，即鼠标停留在控制 <br>
(Tcontrol)上一段时间后，弹出的短提示信息，一部分是当鼠标在控制上或控制和菜单 <br>
获得焦点时，发生的Applicaiton.onShowHint事件。最后都调用Application.ActivateH <br>
int方法，而在ActivateHint方法中，在处理了与该控制相连的Action的Hint字符串之后 <br>
，并没有将Action返回的Hint字符串的短提示取出来。所以会把整个Hint字符串显示出 <br>
来。修改后的函数如下，（修改用注释给出，方法很长只给出部分）是：procedure <br>
TApplication.ActivateHint(CursorPos: TPoint); <br>
... <br>
... <br>
begin <br>
FHintActive := False; <br>
if FShowHint and (FHintControl <> nil) and ForegroundTask and <br>
(FHintControl = GetHintControl(FindDragTarget(CursorPos, True))) then <br>
begin <br>
HintInfo.HintControl := FHintControl; <br>
HintInfo.HintPos := CursorPos; <br>
Inc(HintInfo.HintPos.Y, GetCursorHeightMargin); <br>
HintInfo.HintMaxWidth := Screen.Width; <br>
HintInfo.HintColor := FHintColor; <br>
HintInfo.CursorRect := FHintControl.BoundsRect; <br>
ClientOrigin := FHintControl.ClientOrigin; <br>
ParentOrigin.X := 0; <br>
ParentOrigin.Y := 0; <br>
if FHintControl.Parent <> nil then <br>
ParentOrigin := FHintControl.Parent.ClientOrigin <br>
else if (FHintControl is TWinControl) and <br>
(TWinControl(FHintControl).ParentWindow <> 0) then <br>
Windows.ClientToScreen(TWinControl(FHintControl).ParentWindow, <br>
ParentOrigin); <br>
OffsetRect(HintInfo.CursorRect, ParentOrigin.X - ClientOrigin.X, <br>
ParentOrigin.Y - ClientOrigin.Y); <br>
HintInfo.CursorPos := FHintControl.ScreenToClient(CursorPos); <br>
HintInfo.HintStr := GetShortHint(GetHint(FHintControl)); <br>
HintInfo.ReshowTimeout := 0; <br>
HintInfo.HideTimeout := FHintHidePause; <br>
HintInfo.HintWindowClass := HintWindowClass; <br>
HintInfo.HintData := nil; <br>
HintInfo.HintData := nil; <br>
CanShow := FHintControl.Perform(CM_HINTSHOW, 0, Longint(@HintInfo)) = 0; <br>
// Add By Red Forks <br>
HintInfo.HintStr := GetShortHint(HintInfo.HintStr); <br>
// Add End <br>
if CanShow and Assigned(FOnShowHint) then <br>
FOnShowHint(HintInfo.HintStr, CanShow, HintInfo); <br>
FHintActive := CanShow; <br>
if FHintActive and (HintInfo.HintStr <> '') then <br>
begin <br>
ValidateHintWindow(HintInfo.HintWindowClass); <br>
{ make the hint have the same BiDiMode as the activating control } <br>
FHintWindow.BiDiMode := FHintControl.BiDiMode; <br>
{ calculate the width of the hint based on HintStr and MaxWidth } <br>
with HintInfo do <br>
HintWinRect := FHintWindow.CalcHintRect(HintMaxWidth, HintStr, <br>
HintData); <br>
OffsetRect(HintWinRect, HintInfo.HintPos.X, HintInfo.HintPos.Y); <br>
if FHintWindow.UseRightToLeftAlignment then <br>
with HintWinRect do <br>
begin <br>
Dec(Left, FHintWindow.Canvas.TextWidth(HintInfo.HintStr) + 5); <br>
Dec(Right, FHintWindow.Canvas.TextWidth(HintInfo.HintStr) + 5); <br>
end; <br>
.... <br>
.... <br>
end; <br>
2. 当控制或菜单的Hint属性是空字符串时，不管与之相连的Action是否提供Hint属性， <br>
都不会发生Application的onShowHint方法。 分析：Hint系统首先取出Hint字符串， <br>
若Hint时空串，则不会发生Application.onShowHint，但是，Delphi的取Hint字符串的 <br>
方法忽略了Control的与之相连的Action的Hint，所以产生这个Bug,解决（修改用注释给 <br>
出）：$(Delphi)\source\vcl\forms.pas <br>
function GetHint(Control: TControl): string; <br>
begin <br>
while Control <> nil do <br>
if Control.Hint = '' then <br>
Control := Control.Parent <br>
else <br>
begin <br>
Result := Control.Hint; <br>
// Add by Red Forks <br>
if Assigned(Control.Action) and (Control.Action is TCustomAction) then <br>
TCustomAction(Control.Action).DoHint(result); <br>
// Add end <br>
Exit; <br>
Action(Control.Action).DoHint(result); <br>
// Add end <br>
Exit; <br>
end; <br>
Result := ''; <br>
end; <br>
<br>
-- <br>
※ 来源:·BBS 水木清华站 bbs.net.tsinghua.edu.cn·[FROM: 202.119.199.100] <br>
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