C#.Net组件开发(高级篇) - 使用自定义TypeConverter生成设计时代码

C# Code:

/// <summary>
/// 测试用的Component组件
/// </summary>
public partial class TestComponent : Component
{
   //使用.Net自带的InstanceDescriptor生成设计时代码
   private Guid _MyID;
   
   //使用自定义TypeConverter生成设计时代码
   private MyPoint _MyPoint;
   
   //使用自定义TypeConverter生成设计时代码
   private Person _Person;
   
   [Browsable(true)]
   public Guid MyID
   {
      get { return _MyID; }
      set { _MyID = value; }
   }
   
   [Browsable(true)]
   public MyPoint MyPoint
   {
      get { return _MyPoint; }
      set { _MyPoint = value; }
   }
   
   [Browsable(true)]
   public Person Person
   {
      get
      {
         return _Person;
      }
      
      set
      {
         this._Person = value;
      }
   }
}

//来源:C/S框架网(www.csframework.com) QQ:1980854898

C# Code:

/// <summary>
/// 生成设计时代码的对象
/// </summary>
[TypeConverter(typeof(PersonConverter))] //自定义类型转换器
//[TypeConverter(typeof(PersonConverterExpandable))]//试验第二种类型转换器
public class Person
{
   private string _FirstName = "";
   private string _LastName = "";
   private int _Age = 0;
   
   public Person(string firstName, string lastName, int age)
   {
      _FirstName = firstName;
      _LastName = lastName;
      _Age = age;
   }
   
   public int Age
   {
      get { return _Age; }
      set { _Age = value; }
   }
   
   public string FirstName
   {
      get { return _FirstName; }
      set { _FirstName = value; }
   }
   
   public string LastName
   {
      get { return _LastName; }
      set { _LastName = value; }
   }
   
}

//来源:C/S框架网(www.csframework.com) QQ:1980854898

C# Code:

/// <summary>
/// Person对象的类型转换器实现
/// </summary>
public class PersonConverter : TypeConverter
{
   public PersonConverter() { }
   
   public override bool CanConvertFrom(ITypeDescriptorContext context,
   Type sourceType)
   {
      if (sourceType == typeof(string)) return true;//字符串，如："Jonny,Sun,33"
      return base.CanConvertFrom(context, sourceType);
   }
   
   public override bool CanConvertTo(ITypeDescriptorContext context, Type destinationType)
   {
      if (destinationType == typeof(string)) return true;
      if (destinationType == typeof(InstanceDescriptor)) return true;
      
      return base.CanConvertTo(context, destinationType);
   }
   
   public override object ConvertFrom(ITypeDescriptorContext context, CultureInfo culture, object value)
   {
      string s = value as string;
      
      if (s == null) return base.ConvertFrom(context, culture, value);
      
      //字符串，如："Jonny,Sun,33"
      string[] ps = s.Split(new char[] { char.Parse(",") });
      
      if (ps.Length != 3)
      throw new ArgumentException("Failed to parse Text(" s
      ") expected text in the format \"FirstName,LastName,Age.\"");
      
      //解析字符串并实例化对象
      return new Person(ps[0], ps[1], int.Parse(ps[2]));
   }
   
   public override object ConvertTo(ITypeDescriptorContext context,
   CultureInfo culture,
   object value,
   Type destinationType)
   {
      //将对象转换为字符串，如："Jonny,Sun,33"
      if ((destinationType == typeof(string)) &&& (value is Person))
      return ((Person)value).FirstName "," ((Person)value).LastName "," ((Person)value).Age.ToString();
      
      //生成设计时的构造器代码
      // this.testComponent1.Person = new CSFramework.MyTypeConverter.Person("Jonny", "Sun", 33);
      if (destinationType == typeof(InstanceDescriptor) & value is Person)
      {
         Person p = (Person)value;
         ConstructorInfo ctor = typeof(Person).GetConstructor(
         new Type[] { typeof(string), typeof(string), typeof(int) });
         return new InstanceDescriptor(ctor, new object[] { p.FirstName, p.LastName, p.Age });
      }
      
      return base.ConvertTo(context, culture, value, destinationType);
   }
   
   public override object CreateInstance(ITypeDescriptorContext context,
   IDictionary propertyValues)
   {
      string s1 = (string)propertyValues["FirstName"];
      string s2 = (string)propertyValues["LastName"];
      int age = (int)propertyValues["Age"];
      
      return new Person(s1, s2, age);//创建实例
   }
   
   public override PropertyDescriptorCollection GetProperties(
   ITypeDescriptorContext context,
   object value, Attribute[] attributes)
   {
      if (value is Person)
      return TypeDescriptor.GetProperties(value, attributes);
      
      return base.GetProperties(context, value, attributes);
   }
   
   public override bool GetCreateInstanceSupported(ITypeDescriptorContext context)
   {
      return true;
   }
   
   public override bool GetPropertiesSupported(ITypeDescriptorContext context)
   {
      return true;
   }
   
}

//来源:C/S框架网(www.csframework.com) QQ:1980854898