Memo.GetTextBuf(Buffer, Size 1);
P := SearchBuf(Buffer, Size, Memo.SelStart,
Memo.SelLength,SearchString, Options);
if P <> nil then
begin
Memo.SelStart := P - Buffer;
Memo.SelLength := Length(SearchString);
Result := True;
end;
finally
StrDispose(Buffer);
end;
end;
function SearchBuf(Buf: PChar; BufLen: Integer;
SelStart, SelLength: Integer;
SearchString: String;
Options: TFindOptions): PChar;
var
SearchCount, I: Integer;
C: Char;
Direction: Shortint;
CharMap: array [Char] of Char;
function FindNextWordStart(var BufPtr: PChar): Boolean;
begin { (True XOR N) is equivalent to
(not N) }
Result := False; { (False XOR N) is equivalent
to (N) }
{ When Direction is forward (1), skip non
delimiters, then skip delimiters. }
{ When Direction is backward (-1), skip delims, then
skip non delims }
while (SearchCount > 0) and
((Direction = 1) xor (BufPtr^ in
WordDelimiters)) do
begin
Inc(BufPtr, Direction);
Dec(SearchCount);
end;
while (SearchCount > 0) and
((Direction = -1) xor (BufPtr^ in
WordDelimiters)) do
begin
Inc(BufPtr, Direction);
Dec(SearchCount);
end;
Result := SearchCount > 0;
if Direction = -1 then
begin { back up one char, to leave ptr on first non
delim }
Dec(BufPtr, Direction);
Inc(SearchCount);
end;
end;
begin
Result := nil;
if BufLen <= 0 then Exit;
if frDown in Options then
begin
Direction := 1;
Inc(SelStart, SelLength); { start search past end of
selection }
SearchCount := BufLen - SelStart - Length(SearchString);
if SearchCount < 0 then Exit;
if Longint(SelStart) SearchCount > BufLen then
Exit;
end
else
begin
Direction := -1;
Dec(SelStart, Length(SearchString));
SearchCount := SelStart;
end;
if (SelStart < 0) or (SelStart > BufLen) then Exit;
Result := @Buf[SelStart];
{ Using a Char map array is faster than calling
AnsiUpper on every character }
for C := Low(CharMap) to High(CharMap) do
CharMap[C] := C;
if not (frMatchCase in Options) then
begin
AnsiUpperBuff(PChar(@CharMap), sizeof(CharMap));
AnsiUpperBuff(@SearchString[1],
Length(SearchString));
end;
while SearchCount > 0 do
begin
if frWholeWord in Options then
if not FindNextWordStart(Result) then Break;
I := 0;
while (CharMap[Result[I]] = SearchString[I 1]) do
begin
Inc(I);
if I >= Length(SearchString) then
begin
if (not (frWholeWord in Options)) or
(SearchCount = 0) or
(Result[I] in WordDelimiters) then
Exit;
Break;
end;
end;
Inc(Result, Direction);
Dec(SearchCount);
end;
Result := nil;
end;
end.
4.4.3 替换对话框部件
替换对话框部件为应用程序提供替换对话框。如图
4.9。它包括查找对话框的所有功能，此外还允许使用者更换被选中的字符串。FindText 属性是应用程序需查找的字符串。ReplaceText属性是被选中字符的替换字符串。Options 属性决定对话框的显示方式。其值如表4.3所示。与查找对话框一样，替换对话框亦有
OnFind 事件。用户输入查找字符串并按FindNext按钮时，发生OnFind 事件。用户选择Replace 或ReplacAll 时， 对话框发生OnRelpace事件，要替换的字符串存入ReplaceText属性中，要编写相应的代码以支持替换功能。表4.3 替换对话框的Options属性的取值及含义
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
取值 含义
────────────────────────────────────────
frRelpace 如果是真值， 应用程序将ReplaceText 属性中的字符串替换
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