Delphi10.3关键字自动填充完成AutoComplete

声明两个全局变量

var
aStringList: TStringList; //读取 关键字
aMemoInput:string;       //当前 已输入 项

procedure TSearchReplaceDemoForm.FormCreate(Sender: TObject);
begin
 aStringList:=TStringList.Create;
 aStringList.LoadFromFile('keyWord.txt');  //从文件加载 关键字
end;

拖一个ListBox,命名为ListBox_keyWords

procedure TSearchReplaceDemoForm.ListBox_keyWordsKeyPress(Sender: TObject;
  var Key: Char);
var  tempStr:string;
begin
 if key=#27  then   //esc
     begin
     ListBox_keyWords.Visible:=false;
     SynEditor.SetFocus;
     aMemoInput:='';
     end;

  if key =#13  then  begin    //回车键

      tempStr:=  ListBox_keyWords.Items[ListBox_keyWords.ItemIndex] ;

      SynEditor.SelText := rightstr(  tempStr ,length(tempStr)-length(aMemoInput));
      ListBox_keyWords.Visible:=false;
      SynEditor.SetFocus;
      aMemoInput:='';
  end;
end;

鼠标双击，选择

procedure TSearchReplaceDemoForm.ListBox_keyWordsDblClick(Sender: TObject);
begin
var    tempStr: string;
begin
  if ListBox_keyWords.ItemIndex >= 0 then
  begin
      tempStr:=  ListBox_keyWords.Items[ListBox_keyWords.ItemIndex] ;
      SynEditor.SelText := rightstr(  tempStr ,length(tempStr)-length(aMemoInput));
      ListBox_keyWords.Visible:=false;
      SynEditor.SetFocus;

       aMemoInput:='';
  end;
end;
end;

 假设SynEditor为Memo类型

procedure TSearchReplaceDemoForm.SynEditorKeyDown(Sender: TObject;
  var Key: Word; Shift: TShiftState);
begin
 if ( key=VK_DOWN)  and (ListBox_keyWords.Visible)     then begin //按 向下键，选择
  ListBox_keyWords.SetFocus;
   ListBox_keyWords.ItemIndex:=0;

    exit;
  end;

 if ( key=VK_BACK)     then begin // 向后删除键
    aMemoInput:=leftstr(aMemoInput,length(aMemoInput)-1) ;
   ListBox_keyWords_Refresh(aMemoInput);
     exit;
  end;

 if ( key=VK_ESCAPE ) or(key= VK_RETURN)    then begin // ESC  和 回车
   ListBox_keyWords.Visible:= false;
   aMemoInput:='';
   exit;
  end;
end;

procedure TSearchReplaceDemoForm.SynEditorKeyPress(Sender: TObject;
  var Key: Char);
begin
 if CharInSet( key , ['a'..'z','A'..'Z','_']){ or (Key > #127)}  then   begin
  aMemoInput:=aMemoInput+key;
  ListBox_keyWords_Refresh(aMemoInput);
 end;

 if tulaterIsSeparator(key ) then     begin   //输入 间隔符， ListBox 消失
     aMemoInput:='' ;
    ListBox_keyWords.Visible:=false;
  end;
end;