(一). 概述

        1. 当鼠标悬浮到控件对象上,  会弹出此自定义控件.

        2. 具有通用性, 只要支持 onmouseenter/onmouseleave 等几个事件方法的目标控件都可以使用此控件.

        3. 此控件与前面自定义控件[右击弹出菜单]控件有些类似,  区别是这个控件客户端JavaScript部分有些麻烦.

(二). 运行如图

  

(三). 用法

   1. 将FloatTraceMenu控件Dll添加引用到Web站点工程中

   2. 从工具箱拖动一个FloatTraceMenu控件和另一个支持onmouseenter/onmouseleave 等事件

       的控件到设计器中, 比如:     1 /// 

  2     /// Author: [ ChengKing(ZhengJian) ] 

  3     /// Blog:   Http://blog.csdn.net/ChengKing

  4     /// Date:   2007/4/3

  5     /// 

  6      [DefaultProperty( " TargetControl " )]

  7      [ToolboxData( " <{0}:FloatTraceMenu runat=server> " )]

  8       // [Designer(typeof(System.ComponentModel.Design.DesignerCollection))]

  9       public   class  FloatTraceMenu : Control, IComponent

 10      {

 11 

 12          [Bindable( true )]

 13          [Category( " Appearance " )]

 14          [DefaultValue( " [FloatTraceMenu / " FloatTraceMenu1/ " ] " )]

 15          [Localizable( true )]

 16           public   string  Text

 17          {

 18               get

 19              {

 20                  String s  =  (String)ViewState[ " Text " ];

 21                   return  ((s  ==   null )  ?  String.Empty : s);

 22              }

 23 

 24               set

 25              {

 26                  ViewState[ " Text " ]  =  value;

 27              }

 28          }

 29 

 30          [Bindable( true )]

 31          [Category( " Appearance " )]

 32          [DefaultValue( "" )]

 33          [Description( " 设置此控件的寄主控件 " )]

 34          [TypeConverter( typeof (ControlIDConverter))]  

 35           public   string  TargetControl

 36          {

 37               get

 38              {

 39                  String s  =  (String)ViewState[ " TargetControl " ];

 40                   return  ((s  ==   null )  ?  String.Empty : s);                                                

 41              }

 42               set

 43              {

 44                  ViewState[ " TargetControl " ]  =  value;

 45              }

 46          }

 47 

 48           protected   override   void  Render(HtmlTextWriter writer)

 49          {

 50               if  (DesignMode)

 51              {

 52                   this .Controls.Clear();                

 53                  LiteralControl lc  =   new  LiteralControl();

 54                  lc.Text  =   this .Text;                

 55                   this .Controls.Add(lc);                

 56              }

 57               base .Render(writer);            

 58          }

 59 

 60           protected   override   void  CreateChildControls()

 61          {            

 62               base .CreateChildControls();

 63          }

 64 

 65           protected   override   void  OnPreRender(EventArgs e)

 66          {

 67 

 68               if  ( ! Page.ClientScript.IsClientScriptBlockRegistered( " BuildMenu " ))

 69              {

 70                  Page.ClientScript.RegisterClientScriptBlock( this .GetType(),  " BuildMenu " ,

 71                       " <script type='text/javascript' src='JScript.js'></script> " );

 72              }

 73              

 74               // GridView增加FloatMenu

 75              Control targetControl  =   this .FindControl(TargetControl);

 76 

 77               // 给GridView头增加FloatMenu

 78               // Control targetControl = this.FindControl(TargetControl).Controls[0].Controls[0];

 79 

 80              StringBuilder strInitScript  =   new  StringBuilder();

 81               if  (targetControl  !=   null )

 82              {                

 83                  strInitScript.Append( " <script text/javascript>  " );

 84                  strInitScript.Append( "    writeStyle(); makeMenu(); var obj; " );

 85                  strInitScript.Append( "    if( document.all&&window.print )  " );

 86                  strInitScript.Append( "    {  " );

 87                  strInitScript.Append( "       var objClientId = ' "   +  targetControl.ClientID  +   " '; " );

 88                  strInitScript.Append( "       if(objClientId != null)  " );

 89                  strInitScript.Append( "       {

" );

 90                  strInitScript.Append( "          obj = document.getElementById(objClientId); " );

 91                  strInitScript.Append( "          document.onclick = forcehideMenu; " );

 92                   // strInitScript.Append("         obj.onmouseover = showMenu;");

 93                  strInitScript.Append( "          obj.onmouseenter = showMenu; " );

 94                   // strInitScript.Append("         obj.onmouseout = hideMenu;");

 95                  strInitScript.Append( "          obj.onmouseleave = hideMenu; " );

 96                  strInitScript.Append( "          obj.onmousemove = moveMenu; " );

 97                  strInitScript.Append( "          obj.oncontextmenu = showMenu; " );

 98                  strInitScript.Append( "       } " );

 99                  strInitScript.Append( "       else {alert('Please Set TargetControl Property!')} " );

100                  strInitScript.Append( "    }  " );

101                  strInitScript.Append( " </script> " );

102              }

103               else

104              {

105                  strInitScript.Append( " <script text/javascript>  " );

106                  strInitScript.Append( "    alert('Please Set TargetControl Property!');  " );

107                  strInitScript.Append( " </script> " );

108              }

109               if  ( ! Page.ClientScript.IsStartupScriptRegistered( " InitScript " ))

110              {

111                  Page.ClientScript.RegisterStartupScript( this .GetType(),  " InitScript " ,

112                      strInitScript.ToString());

113              }

114             

115               base .OnPreRender(e);

116          }        

117      }