C# PropertyGrid使用總結

1. 只有public的property能顯示出來，可以通過BrowsableAttribute來控制是否顯示，通過CategoryAttribute設置分類，通過DescriptionAttribute設置描述，Attribute可以加在Class上，也可以加在屬性上，屬性上的Attribute優先級更高；

2. enum會自動使用列表框表示；

3. 自帶輸入有效性檢查，如int類型輸入double數值，會彈出提示對話框；

4. 基本類型Array：增加刪除只能通過彈出的集合編輯器，修改可以直接展開，值為null時，可以通過集合編輯器創建；

5. 基本類型List：增刪改都只能通過集合編輯器，值為null時，能打開集合編輯器，但不能保存結果，所以必須初始化；

6. ReadOnlyAttribute設置為true時，顯示為灰色；對List無效，可以打開集合編輯器，在集合編輯器內可以進行增刪改；應用於Array時，不能打開集合編輯器，即不能增刪，但可以通過展開的方式修改Array元素；

7. 對象：值顯示Object.ToString()；Class上加了[TypeConverter(typeof(ExpandableObjectConverter))]之后（也可以加在屬性上），才能展開編輯，否則顯示為灰色只讀；不初始化什么也干不了；

8. 基類類型派生類對象：與普通對象沒有區別，[TypeConverter(typeof(ExpandableObjectConverter))]加在基類上即可；

9. 對象Array：增加刪除只能通過彈出的集合編輯器，修改可以直接展開，值為null時，可以通過集合編輯器創建；

10. 對象List：增加刪除修改只能通過彈出的集合編輯器，值為null時，能打開集合編輯器，但不能保存結果，所以必須初始化；

11. Hashtable和Dictionary能打開集合編輯器，但不能編輯；

12. 通過MyDoubleConverter實現Double類型只顯示小數點后兩位：

    public class MyDoubleConverter : DoubleConverter
    {
        public override object ConvertTo(ITypeDescriptorContext context, CultureInfo culture, object value, Type destinationType)
        {
            if (destinationType == typeof(string))
            {
                return string.Format("{0:0.00}", value);
            }
            return base.ConvertTo(context, culture, value, destinationType);
        }
    }

13. 通過TypeConverter實現用字符串表示對象

    [TypeConverter(typeof(StudentConverter))]
    public class Student
    {
        public Student(string name, int age)
        {
            Name = name;
            Age = age;
        }
        public string Name { get; set; }
        public int Age { get; set; }

        public static Student FromString(string s)
        {
            string name = "Default";
            int age = 0;
            string[] splits = s.Split(',');
            if (splits.Length == 2)
            {
                name = splits[0];
                int.TryParse(splits[1], out age);
            }
            return new Student(name, age);
        }

        public override string ToString()
        {
            return string.Format("{0},{1}", Name, Age);
        }
    }

    public class StudentConverter : TypeConverter
    {
        public override bool CanConvertFrom(System.ComponentModel.ITypeDescriptorContext context, Type sourceType)
        {
            if (sourceType == typeof(string))
            {
                return true;
            }
            return base.CanConvertFrom(context, sourceType);
        }
        public override object ConvertFrom(ITypeDescriptorContext context, System.Globalization.CultureInfo culture, object value)
        {
            Student result = null;
            if ((value as string) != null)
            {
                result = Student.FromString(value as string);
            }
            return result;
        }
        public override bool CanConvertTo(ITypeDescriptorContext context, Type destinationType)
        {
            if (destinationType == typeof(string))
            {
                return true;
            }
            return base.CanConvertTo(context, destinationType);
        }
        public override object ConvertTo(ITypeDescriptorContext context, System.Globalization.CultureInfo culture, object value, Type destinationType)
        {
            if (destinationType == typeof(string))
            {
                return value.ToString();
            }
            return base.ConvertTo(context, culture, value, destinationType);
        }
    }

14. 使用UITypeEditor實現文件或目錄選擇

        // 需要在項目里添加引用：程序集|框架|System.Design
        [Editor(typeof(FileNameEditor), typeof(UITypeEditor))]
        public string FileName { get; set; }

        [Editor(typeof(FolderNameEditor), typeof(UITypeEditor))]
        public string FolderName { get; set; }

15. 使用自定義的下拉式編輯界面

    public class MyAddress
    {
        public string Province { get; set; }
        public string City { get; set; }
        public override string ToString()
        {
            return string.Format("{0}-{1}", Province, City);
        }
    }

    public class MyAddressEditor : UITypeEditor
    {
        public override UITypeEditorEditStyle GetEditStyle(ITypeDescriptorContext context)
        {
            return UITypeEditorEditStyle.DropDown;
        }

        public override object EditValue(ITypeDescriptorContext context, IServiceProvider provider, object value)
        {
            IWindowsFormsEditorService service = provider.GetService(typeof(IWindowsFormsEditorService)) as IWindowsFormsEditorService;
            if (service != null)
            {
                service.DropDownControl(new MyEditorControl(value as MyAddress));
            }
            return value;
        }
    }

    // 實現兩個ComboBox用來編輯MyAddress的屬性
    public partial class MyEditorControl : UserControl
    {
        private MyAddress _address;
        public MyEditorControl(MyAddress address)
        {
            InitializeComponent();
            _address = address;
            comboBoxProvince.Text = _address.Province;
            comboBoxCity.Text = _address.City;
        }

        private void comboBoxProvince_SelectedIndexChanged(object sender, EventArgs e)
        {
            _address.Province = comboBoxProvince.Text;
        }

        private void comboBoxCity_SelectedIndexChanged(object sender, EventArgs e)
        {
            _address.City = comboBoxCity.Text;
        }
    }

    // MyAddress屬性聲明
    [Editor(typeof(MyAddressEditor), typeof(UITypeEditor))]
    public MyAddress Address { get; set; }

效果如圖：

16. 實現彈出式編輯對話框，只要將UserControl改成Form，EditStyle改成Modal，service.DropDownControl改成service.ShowDialog

    public partial class MyEditorForm : Form
    {
        private MyAddress _address;
        public MyEditorForm(MyAddress address)
        {
            InitializeComponent();
            _address = address;
            comboBoxProvince.Text = _address.Province;
            comboBoxCity.Text = _address.City;
        }

        private void comboBoxProvince_SelectedIndexChanged(object sender, EventArgs e)
        {
            _address.Province = comboBoxProvince.Text;
        }

        private void comboBoxCity_SelectedIndexChanged(object sender, EventArgs e)
        {
            _address.City = comboBoxCity.Text;
        }
    }

    public class MyAddressEditor : UITypeEditor
    {
        public override UITypeEditorEditStyle GetEditStyle(ITypeDescriptorContext context)
        {
            return UITypeEditorEditStyle.Modal;
        }

        public override object EditValue(ITypeDescriptorContext context, IServiceProvider provider, object value)
        {
            IWindowsFormsEditorService service = provider.GetService(typeof(IWindowsFormsEditorService)) as IWindowsFormsEditorService;
            if (service != null)
            {
                service.ShowDialog(new MyEditorForm(value as MyAddress));
            }
            return value;
        }
    }

17. 密碼表示：[PasswordPropertyText(true)]

18. 動態顯示/隱藏屬性

    class MyData
    {
        public static void SetPropertyAttribute(object obj, string propertyName, Type attrType, string attrField, object value)
        {
            PropertyDescriptorCollection props = TypeDescriptor.GetProperties(obj);
            Attribute attr = props[propertyName].Attributes[attrType];
            FieldInfo field = attrType.GetField(attrField, BindingFlags.Instance | BindingFlags.NonPublic);
            field.SetValue(attr, value);
        }

        private bool _ShowPassword = false;
        public bool ShowPassword
        {
            get { return _ShowPassword; }
            set
            {
                _ShowPassword = value;
                SetPropertyAttribute(this, "Password", typeof(BrowsableAttribute), "browsable", _ShowPassword);
            }
        }

        [PasswordPropertyText(true)]
        [Browsable(true)]
        public string Password { get; set; }
    }

    public partial class MainFrm : Form
    {
        // 不添加PropertyValueChanged事件，不能實現動態顯示/隱藏
        private void myData_PropertyValueChanged(object s, PropertyValueChangedEventArgs e)
        {
            this.myData.SelectedObject = this.myData.SelectedObject;
        }
    }

19. 提供下拉選項的string

    public class ListStringConverter : StringConverter
    {
        public override bool GetStandardValuesSupported(ITypeDescriptorContext context)
        {
            return true;
        }

        public override StandardValuesCollection GetStandardValues(ITypeDescriptorContext context)
        {
            return new StandardValuesCollection(new string[] { "A", "B" });
        }

        public override bool GetStandardValuesExclusive(ITypeDescriptorContext context)
        {
            return false;
        }
    }

    [TypeConverter(typeof(ListStringConverter))]
    public string Name { get; set; }