自定义控件开发5--自定义属性编辑器(Modal,DropDown)

要实现这样的效果,我们只需要做2件事情。

1. 在控件类库中,添加一个WindowForm类,然后编辑相应的界面,并初始化

因为默认情况下 控件在designer.cs中定义为private,所以我们将他改为Public。

  public   partial   class  CategoryWindow : Form
    {
         public  CategoryWindow()
        {
            InitializeComponent();
            SetSelectData();
        }
         public   void  SetSelectData()
        {
             try
            {
                 this .comboBox1.Items.Add( " 水果 " );
                 this .comboBox1.Items.Add( " 蔬菜 " );
                 this .comboBox1.Items.Add( " 肉类 " );
                 this .comboBox1.Items.Add( " 蛋类 " );
                 this .comboBox1.Items.Add( " 面食 " );
                 this .comboBox1.SelectedItem  =  comboBox1.Items[ 0 ];
            }
             catch  (Exception eee)
            {
                 throw  eee;
            }
             finally
            {
            }
        }
    }

2. 定制自己的UITypeEditor类。

  public   class  CategoryModalEditor : System.Drawing.Design.UITypeEditor
    {
         public  CategoryModalEditor()
        {
        }
         public   override  System.Drawing.Design.UITypeEditorEditStyle GetEditStyle(System.ComponentModel.ITypeDescriptorContext context)
        {
             return  UITypeEditorEditStyle.Modal;
        }
         public   override   object  EditValue(System.ComponentModel.ITypeDescriptorContext context, 
            System.IServiceProvider provider,  object  value)
        {
            IWindowsFormsEditorService service  =  
                (IWindowsFormsEditorService)provider.GetService( typeof (IWindowsFormsEditorService));
             if  (service  ==   null )
            {
                 return   null ;
            }
            CategoryWindow form  =   new  CategoryWindow();
             if  (service.ShowDialog(form)  ==  DialogResult.OK)
            {
                 return  form.comboBox1.SelectedItem;
            }
             return  value;
        }
    }

 2. 属性下拉编辑器.

1.在ClassLibrary中,新建一个UserControl(CategoryDorpDown.cs).

2.实现自定义UITypeEditor.

3.因为WindowForm里的控件在Designer.cs声明为Private,如果声明为Public,则在自定义UITypeEditor中引用不到控件,所以我们需要

ComboBox obj = dropform.Controls[2] as ComboBox;需要找到下拉控件 并根据Value 参数赋值,但我们要判断是否控件为NULL和是否为"".

赋值为obj.Text=value as string.

  public   class  CategoryDropDownEditor : System.Drawing.Design.UITypeEditor
    {
         public  CategoryDropDownEditor()
        {
        }
         public   override  System.Drawing.Design.UITypeEditorEditStyle
            GetEditStyle(System.ComponentModel.ITypeDescriptorContext context)
        {
             // 指定编辑样式为下拉形状, 且基于Control 类型
             return  UITypeEditorEditStyle.DropDown;
        }
         public   override   object  EditValue(System.ComponentModel.ITypeDescriptorContext context, 
            System.IServiceProvider provider,  object  value)
        {
             // 取得编辑器服务对象
            IWindowsFormsEditorService service  =  
                (IWindowsFormsEditorService)provider.GetService( typeof (IWindowsFormsEditorService));
             if  (service  ==   null )
            {
                 return   null ;
            }
      
             // 定义一个用户控件对象
             string  original  =   string .Empty;
             string  strReturn  =   string .Empty;
            CategoryDorpDown dropform  =   new  CategoryDorpDown(service);
            ComboBox obj  =  dropform.Controls[ 2 ]  as  ComboBox;
             if  (obj  !=   null )
            {
                 if  (value  !=   null && value.ToString() != "" )
                {
                    obj.Text =  ( string )value;
                }
            }
            service.DropDownControl(dropform);
            strReturn  =  dropform.strReturnValue;
             if  (strReturn  +  String.Empty  !=  String.Empty)
            {
                 return  strReturn;
            }
             return  ( string )value;
        }
    }

 3.

 

在这个自定义属性中,我继承StringConverter并通过返回一个string数组来实现下拉：

代码

     public   class  CustomCollectionPropertyConverter : StringConverter
    {
         public   override   bool  GetStandardValuesSupported(ITypeDescriptorContext
context)
        {
             return   true ;
        }
         public   override   bool  GetStandardValuesExclusive(ITypeDescriptorContext
        context)
        {
             return   false ;
        }
         public   override  StandardValuesCollection
        GetStandardValues(ITypeDescriptorContext context)
        {
             string [] strArray  =   new   string [] {  " 水果 " ,  " 蔬菜 " ,  " 肉食 " ,  " 面食 " ,  " 蛋类 "  };
            StandardValuesCollection returnStandardValuesCollection  =   new
            StandardValuesCollection(strArray);
             return  returnStandardValuesCollection;
        }
    }

没有特别之处,只是当我们重写GetStandardValuesExclusive为true是，我们就不能手动输入字符串，只能根据下拉选择值.