dbgrid函数问题 ( 积分: 50 )

procedure TForm1.DBGrid1DragOver(Sender, Source: TObject; X, Y: Integer;
State: TDragState; var Accept: Boolean);????是个什么函数??
begin
Accept:=True;什么意思???
end;

procedure TForm1.DBGrid1DragDrop(Sender, Source: TObject; X, Y: Integer);和上面的函数有什么不同
begin
if Source<>ComboBox1 then
Exit;
with Sender as TDBGrid do
begin
Perform(wm_LButtonDown,0,MakeLong(x,y));
PerForm(WM_LButtonUp, 0,MakeLong(x,y));
SelectedField.Dataset.edit;
SelectedField.AsString:=ComboBox1.Text;
end;
整个一段有没有帮我解释一下
谢谢
end;

爲了在dbgrid的grid中顯示combobox形式的下拉框作的處理

procedure TForm1.DBGrid1DragOver(Sender, Source: TObject; X, Y: Integer;
State: TDragState; var Accept: Boolean);//拖动时鼠标经过 DBGrid1 时响应的事件
begin
Accept:=True;//是否允许接收拖放的内容
end;

procedure TForm1.DBGrid1DragDrop(Sender, Source: TObject; X, Y: Integer);//拖放时鼠标在 DBGrid1 放开（即拖放的内容“放下”）时响应的事件
begin
if Source<>ComboBox1 then //如果不是从 ComboBox1 拖过来就不处理，直接退出
Exit;
with Sender as TDBGrid do
begin
Perform(wm_LButtonDown,0,MakeLong(x,y));//这两句模仿鼠标左键点击(压下)
PerForm(WM_LButtonUp, 0,MakeLong(x,y));//这两句模仿鼠标左键点击(放开)
SelectedField.Dataset.edit;//数据表进入编辑状态
SelectedField.AsString:=ComboBox1.Text;//将 ComboBox1 的 Text 赋值给选择的字段
end;
end;