Silverlight智能表单实现代码

作者：袖梨 2022-06-25

silverlight智能表单实现代码

控件从工具箱到画板的拖动让我想到了tookit中dragdroptarget控件，工具箱好说用listbox或者treeview，画板就不知道怎么搞了，于是决定自己做dragdrop。

左侧的是一个listbox，右侧红色的是canvas。创建一个类库dragdroplibrary（这个名不知道好不好听）。

点击左侧的listbox，然后移动鼠标到右侧红色部分，松开鼠标控件就放到松开的位置，思路就这么简单。

listbox的xaml：（controls = new string[3] { "textbox", "button", "textblock" };这个是给listbox的数据，测试。。。）

item就一个textblock，我们要注册mouseleftbuttondown事件。

在dragdroplibrary中添加一个类：

show sourceview sourceprint?01 using system.windows;

02 using system.windows.controls;

03 using system.windows.input;

04 using system.windows.media;

05 using system.windows.media.imaging;

06

07 namespace dragdroplibrary

08 {

09     public static class dragdropmanage

10     {

11         private static panel _root, _board;

12         //drop

13         public delegate void drop(dragdropeventargs target);

14         private static drop _ondrag;

15         private static dragdropeventargs eveargs;

16

17         //鼠标拖动时跟随效果

18         private static image _mouseeffert;

19

20         ///

21         /// 拖动之前调用

22         ///

23         /// 根panel（children中包含工具箱和画板）

24         /// 画板

25         public static void register(panel root, panel board)

26         {

27             _root = root;

28             _board = board;

29             if (_root is grid)

30             {

31                 grid.setcolumnspan(_mouseeffert, (_root as grid).columndefinitions.count+1);

32                 grid.setrowspan(_mouseeffert, (_root as grid).rowdefinitions.count+1);

33             }

34         }

35

36         static dragdropmanage()

37         {

38             _mouseeffert = new image();

39         }

40

41         public static void begindrag(object sender, mousebuttoneventargs e, drop drop)

42         {

43             frameworkelement target = sender as frameworkelement;

44             writeablebitmap bitmap = new writeablebitmap(target, new translatetransform());

45             _mouseeffert.source =bitmap;

46             _mouseeffert.height = bitmap.pixelheight;

47             _mouseeffert.width = bitmap.pixelwidth;

48             _root.children.add(_mouseeffert);

49             point position = e.getposition(_root);

50             _mouseeffert.margin = new thickness(position.x, position.y, 0, 0);

51

52             _mouseeffert.horizontalalignment = horizontalalignment.left;

53             _mouseeffert.verticalalignment = verticalalignment.top;

54             _mouseeffert.capturemouse();

55             eveargs = new dragdropeventargs(target);

56

57             _ondrag = drop;

58             _root.mousemove += onrootmousemove;

59             _root.mouseleftbuttonup += onrootmouseleftbuttonup;

60         }

61

62         private static void clear()

63         {

64             _root.mousemove -= onrootmousemove;

65             _root.mouseleftbuttonup -= onrootmouseleftbuttonup;

66             _root.children.remove(_mouseeffert);

67             _ondrag = null;

68             eveargs = null;

69         }

70

71         private static void onrootmouseleftbuttonup(object sender, mousebuttoneventargs e)

72         {

73             eveargs.position = e.getposition(_board);

74             _ondrag(eveargs);

75             clear();

76         }

77

78         private static void onrootmousemove(object sender, mouseeventargs e)

79         {

80             point position = e.getposition(_root);

81             _mouseeffert.margin = new thickness(position.x, position.y, 0, 0);

82

83             point currentposition = e.getposition(_board);

84             if (currentposition.x > 0 && currentposition.x < _board.actualwidth

85                 && currentposition.y > 0 && currentposition.y < _board.actualheight)

86             {

87                 eveargs.accept = true;

88             }

89             else

90             {

91                 eveargs.accept = false;

92             }

93         }

94     }

95 }
show sourceview sourceprint?01 using system;

02 using system.windows;

03

04 namespace dragdroplibrary

05 {

06     public class dragdropeventargs : eventargs

07     {

08         public bool accept { get; set; }

09

10         public point position { get; internal set; }

11

12         public frameworkelement target { get; private set; }

13

14         public dragdropeventargs(frameworkelement target)

15         {

16             target = target;

17             position = new point(0, 0);

18         }

19     }

20 }

这个eventargs类也一并贴出。

dragdropmanage我做成了静态类，我的电脑只有一个鼠标，而且我也没有多点触控的装备，不知道多点触控能不能同时托两个或者更多控件。

在最最最开始，我们需要初始化dragdroplibrary.dragdropmanage.register(layoutroot, boardcanvas);

layoutroot这个都知道，就是程序的根容器，boardcanvas就是上面说的红色的canvas。

textblock鼠标点击事件，这时我们就开始拖动了。drop1是一个方法，用来当我们松开鼠标时的回调方法。

private void onlistboxitemmouseleftbuttondown(object sender, mousebuttoneventargs e)
{
            dragdroplibrary.dragdropmanage.begindrag(sender, e, drop1);
}

show sourceview sourceprint?01 public void drag1(dragdroplibrary.dragdropeventargs target)

02 {

03     if (target.accept)

04     {

05         string name = (target.target as textblock).text;

06         frameworkelement element = null;

07

08         type type = gettypefromstring(name);

09         if (type != null)

10         {

11             element = activator.createinstance(type) as frameworkelement;

12

13             if (target.position != null)

14             {

15                 canvas.setleft(element, target.position.x);

16                 canvas.settop(element, target.position.y);

17             }

18

19             element.;

20             element.;

21

22             boardcanvas.children.add(element);

23         }

24     }

25 }

26 private type gettypefromstring(string typename)

27 {

28     type type = null;

29     typename = "system.windows.controls." + typename;

30     assembly assembly = assembly.load("system.windows, version=2.0.5.0, culture=neutral, publickeytoken=7cec85d7bea7798e");

31

32     type = assembly.gettype(typename);

33     return type;

34 }