.net WinForm用户控件开发--(7)用户控件下拉式属性设置

  这一节我们共同学习下用户控件的下拉式属性设置，可以为用户控件设置属性以下拉框的形式显示出来，效果图如下

     

   这里我们定义一个用户控件，设置一个属性dropdownpropery

   代码如下

   

[csharp]
public partial class uclab : usercontrol 
  { 
      public uclab() 
      { 
          initializecomponent(); 
      } 
 
      
 
      private string dropdownpropery="hello"; 
      [description("下拉属性")] 
      [editor(typeof(droptypedialogeditor),typeof(uitypeeditor))] 
      public string dropdownpropery 
      { 
          get 
          { 
              return dropdownpropery; 
          } 
          set 
          { 
              dropdownpropery = value; 
          } 
      } 
 
      
  } 

  public partial class uclab : usercontrol
    {
        public uclab()
        {
            initializecomponent();
        }

      

        private string dropdownpropery="hello";
        [description("下拉属性")]
        [editor(typeof(droptypedialogeditor),typeof(uitypeeditor))]
        public string dropdownpropery
        {
            get
            {
                return dropdownpropery;
            }
            set
            {
                dropdownpropery = value;
            }
        }

      
    }
    接着我们该属性设置一个下拉式编辑器，代码如下

     

[csharp]
/// <summary>  
   /// 下拉式编辑器  
   /// </summary>  
   public class droptypedialogeditor:uitypeeditor 
   { 
       public override uitypeeditoreditstyle geteditstyle(itypedescriptorcontext context) 
       { 
           if (context!=null&&context.instance!=null) 
           { 
               return uitypeeditoreditstyle.dropdown;//显示下拉箭头  
           } 
           return base.geteditstyle(context); 
       } 
 
       public override object editvalue(itypedescriptorcontext context, iserviceprovider provider, object value) 
       { 
           system.windows.forms.design.iwindowsformseditorservice editorservice = null; 
           if (context!=null&&context.instance!=null&&provider!=null) 
           { 
               editorservice = (system.windows.forms.design.iwindowsformseditorservice)provider.getservice(typeof(system.windows.forms.design.iwindowsformseditorservice)); 
               if (editorservice!=null) 
               { 
                   uclab lab =(uclab)context.instance; 
                   ucdrop drop = new ucdrop(lab.dropdownpropery); 
                   editorservice.dropdowncontrol(drop); 
                   value = drop.result; 
                   return value; 
               } 
 
           } 
           //return base.editvalue(context, provider, value);  
           return value; 
       } 
    
   } 

 /// <summary>
    /// 下拉式编辑器
    /// </summary>
    public class droptypedialogeditor:uitypeeditor
    {
        public override uitypeeditoreditstyle geteditstyle(itypedescriptorcontext context)
        {
            if (context!=null&&context.instance!=null)
            {
                return uitypeeditoreditstyle.dropdown;//显示下拉箭头
            }
            return base.geteditstyle(context);
        }

        public override object editvalue(itypedescriptorcontext context, iserviceprovider provider, object value)
        {
            system.windows.forms.design.iwindowsformseditorservice editorservice = null;
            if (context!=null&&context.instance!=null&&provider!=null)
            {
                editorservice = (system.windows.forms.design.iwindowsformseditorservice)provider.getservice(typeof(system.windows.forms.design.iwindowsformseditorservice));
                if (editorservice!=null)
                {
                    uclab lab =(uclab)context.instance;
                    ucdrop drop = new ucdrop(lab.dropdownpropery);
                    editorservice.dropdowncontrol(drop);
                    value = drop.result;
                    return value;
                }

            }
            //return base.editvalue(context, provider, value);
            return value;
        }
   
    }
   以上代码就可以实现，当我们把用户控件拖动到窗体上，设置该属性，就可以以下拉式窗体显示。