程序中的对话框应用（6）- “替换”对话框

TReplaceDialog组件是TFindDialog类的特殊版本，提示用户查找和替换字符串，与“查找”对话框相同，替换对话框是一个无模式的windows对话框。

代码示例（窗体上添加按钮、RichEdit、ReplaceDialog）：

procedure TForm1.Button1Click(Sender: TObject);//打开替换对话框
begin
  ReplaceDialog1.Top:= 200;
  ReplaceDialog1.Left:= 400;
  ReplaceDialog1.Execute;
end;

procedure TForm1.ReplaceDialog1Find(Sender: TObject);//在文本中查找要替换的内容
var
  FoundAt: LongInt;
  StartPos,Toend: integer;
begin
  with RichEdit1 do
  begin
    if SelLength<> 0 then
    StartPos:= SelStart+ SelLength
    else
      StartPos:= 0;
    Toend:= Length(Text)- StartPos;
    FoundAt:= FindText(ReplaceDialog1.FindText,StartPos,Toend,[stMatchCase]);
    if FoundAt <> -1 then
    begin
      SetFocus;
      SelStart:= FoundAt;
      SelLength:= Length(ReplaceDialog1.FindText);
    end;
  end;
end;

procedure TForm1.ReplaceDialog1Replace(Sender: TObject);
var
  SelPos: Integer;
begin
  //对文本进行单个替换
  if frReplace in ReplaceDialog1.Options then
  begin
    with TReplaceDialog(Sender) do
    begin
      SelPos:= pos(FindText,RichEdit1.Lines.Text);
      if SelPos> 0 then
      begin
        RichEdit1.SelStart:= SelPos- 1;
        RichEdit1.SelLength:= Length(FindText);
        RichEdit1.SelText:= ReplaceText;
      end
      else
        MessageDlg(Concat('Could not find',Findtext,'in Memo1.'),mtError,[mbOK],0);
    end;
    //对文本进行全部替换
    if frReplaceAll in ReplaceDialog1.Options then
    while True do
    begin
      with TReplaceDialog(Sender) do
      begin
        if SelPos= 0 then
        Break;
      SelPos:= Pos(FindText,RichEdit1.Lines.Text);
        if SelPos> 0 then
        begin
          RichEdit1.SelStart:= SelPos- 1;
          RichEdit1.SelLength:= Length(FindText);
          RichEdit1.SelText:= ReplaceText;
        end;
      end;
    end;
  end;
end;