DropEdit

unit DropEdit; interface uses Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs, StdCtrls, ShellApi; type TMyNotifyEvent = procedure (Sender: TObject;FileNames:TStringList) of object; //自定义事件类型。 TDropEdit = class(TEdit) //新的类从TListBox继承 private { Private declarations } FEnabled:Boolean; //属性DropEnabled的内部变量 protected FDropFile:TMyNotifyEvent; //事件指针 procedure DropFiles(var Mes:TMessage);message WM_DROPFILES; procedure FDropEnabled(Enabled:Boolean); //设置DropEnabled属性的过程 { Protected declarations } public constructor Create(AOwner: TComponent);override; destructor Destroy;override; { Public declarations } published property OnDropFiles:TMyNotifyEvent read FDropFile write FDropFile; property DropEnabled:Boolean read FEnabled write FDropEnabled; { Published declarations } end; procedure Register; implementation procedure Register; begin RegisterComponents('HaiouEdit', [TDropEdit]); //注册组件到组件板上 end; constructor TDropEdit.Create(AOwner: TComponent); begin inherited Create(AOwner); FEnabled:=true; //类被构造时，使DropEnabeld的默认值为True end; destructor TDropEdit.Destroy; begin inherited Destroy; end; //改变属性DropEnabled的调用过程 procedure TDropEdit.FDropEnabled(Enabled:Boolean); begin FEnabled:=Enabled; DragAcceptFiles(Self.Handle,Enabled);//设置组件窗口是否接受文件拖放 end; //接受WM_DropFiles消息的过程 procedure TDropEdit.DropFiles(var Mes:TMessage); var FN:TStringList; FileName:array [1..256] of char; sFN:String; i,Count,p:integer; begin FN:=TStringList.Create; Count:=DragQueryFile(Mes.WParam,$FFFFFFFF,@FileName,256);//得到拖放文件的个数 For i:=0 to Count-1 do begin DragQueryFile(mes.WParam,i,@FileName,256);//查询文件名称 sFN:=FileName; p:=pos(chr(0),sFN);//去掉文件名末尾的ASCII码为0的字符 sFN:=copy(sFN,1,p-1); FN.Add(sFN); end; DragFinish(mes.WParam); //释放所使用的资源 if Assigned(FDropFile) then FDropFile(self, FN); //调用事件，并返回文件名列表参数 FN.Free; end; end. { 组件的OnDropFiles事件中写下具体处理拖放操作的代码。 　　例如将所有拖放的文件名加入该列表中，添加代码如下： procedure TForm1.DropEdt1DropFiles(Sender: TObject;FileNames: TStringList); begin DropEdit1.text:=FileNames; end; }