如何为自定义控件添加值为某个结构的属性?

[SadEmprie]

控件TT继承自TextBox，TT中有个public属性MyPro，类型的MyStruct

定义为
public struct MyStruct
{
public byte i;
public byte j;

public MyStruct(byte a, byte b)
{
i = a;
j = b;
}
}


可是为什么控件的属性窗口中，属性MyPro是灰色的？不能像控件的Padding或Size属性那样展开一个属性菜单，然后设置里面的值？

[兔子-顾问]

因为吧struct作为属性的时候，get返回的是属性的副本，所以设计器对值类型属性设置为只读，因为你实际修改了副本的字段并不能对控件本身那个属性有改变。
你用类就可以了。

[DataBox-MDX]

因为你这里只定义了访问属性，没定义设置属性:
public byte i;
public byte j;
改为：

private byte _i;
Public byte i
{
  get {return _i;}
  set { _i=value;}
}
private byte _j;
Public byte j
{
  get {return _j;}
  set { _j=value;}
}

[itrefer]

属性上加标签[Browsable(true), Category("XX"), Description("XX")]

如果想自动选择 试试 枚举 （没试过）

[whrspsoft3723]

看来问题已经解决了

[兔子-顾问]

我想当然了。看这个文章介绍的吧。
http://hi.baidu.com/wanhongnan/blog/item/e0d9863de9901603baa1670a.html/cmtid/122369cfd1137331f9dc6164

[边城的刀声]

如果能编辑才叫有问题呢

[yangqizhong]

我觉得用类，然后把get set 都写出来，一起实现吧

[边城的刀声]

得指定自定义的TypeConverter，我写了个例子

[DefaultProperty("Text")]
    [ToolboxData("<{0}:HasCustomClassProperty runat=server></{0}:HasCustomClassProperty>")]
    public class HasCustomClassProperty : WebControl
    {
        [TypeConverter(typeof(MyStructConverter))]
        [Browsable(true)]
        public MyStruct MyPro
        {
            get { return ViewState["MyPro"] == null ? default(MyStruct) : (MyStruct) ViewState["MyPro"]; }
            set { ViewState["MyPro"] = value; }
        }

        

        protected override void RenderContents(HtmlTextWriter output)
        {
            output.Write(String.Format("i:{0}",MyPro.i));
            output.Write(String.Format("j:{0}", MyPro.j));
        }
    }

    public class MyStructConverter : TypeConverter
    {
        public override bool CanConvertFrom(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)
        {
            if (value is String)
            {
                String[] values = value.ToString().Split(',');
                MyStruct result = new MyStruct(Byte.Parse(values[0]), Byte.Parse(values[1]));
                return result;
            }
            else
            {
                return base.ConvertFrom(context, culture, value);
            }
        }

        public override object ConvertTo(ITypeDescriptorContext context, System.Globalization.CultureInfo culture, object value, Type destinationType)
        {
            if (destinationType == typeof(String))
            {
                MyStruct myStruct = (MyStruct) value;
                return String.Format("{0},{1}", myStruct.i, myStruct.j);
            }
            else
            {
                return base.ConvertTo(context, culture, value, destinationType);
            }
        }

        public override bool CanConvertTo(ITypeDescriptorContext context, Type destinationType)
        {
            if (destinationType == typeof(String))
            {
                return true;
            }
            else
            {
                return base.CanConvertTo(context, destinationType);
            }
        }
    }

    [Serializable]
    public struct MyStruct
    {
        public byte i;
        public byte j;

        public MyStruct(byte a, byte b)
        {
            i = a;
            j = b;
        }
    }

[边城的刀声]

如果想展开分别设置i和j呢？,继承下ExpandableObjectConverter,并公布出i和j

[DefaultProperty("Text")]
    [ToolboxData("<{0}:HasCustomClassProperty runat=server></{0}:HasCustomClassProperty>")]
    public class HasCustomClassProperty : WebControl
    {
        [TypeConverter(typeof(MyStructConverter))]
        [Browsable(true)]
        public MyStruct MyPro
        {
            get { return ViewState["MyPro"] == null ? default(MyStruct) : (MyStruct) ViewState["MyPro"]; }
            set { ViewState["MyPro"] = value; }
        }

        

        protected override void RenderContents(HtmlTextWriter output)
        {
            output.Write(String.Format("i:{0}",MyPro.I));
            output.Write(String.Format("j:{0}", MyPro.J));
        }
    }

    public class MyStructConverter : ExpandableObjectConverter
    {
        public override bool CanConvertFrom(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)
        {
            if (value is String)
            {
                String[] values = value.ToString().Split(',');
                MyStruct result = new MyStruct(Byte.Parse(values[0]), Byte.Parse(values[1]));
                return result;
            }
            else
            {
                return base.ConvertFrom(context, culture, value);
            }
        }

        public override object ConvertTo(ITypeDescriptorContext context, System.Globalization.CultureInfo culture, object value, Type destinationType)
        {
            if (destinationType == typeof(String))
            {
                MyStruct myStruct = (MyStruct) value;
                return String.Format("{0},{1}", myStruct.I, myStruct.J);
            }
            else
            {
                return base.ConvertTo(context, culture, value, destinationType);
            }
        }

        public override bool CanConvertTo(ITypeDescriptorContext context, Type destinationType)
        {
            if (destinationType == typeof(String))
            {
                return true;
            }
            else
            {
                return base.CanConvertTo(context, destinationType);
            }
        }
    }

    [Serializable]
    public struct MyStruct
    {
        private byte i;
        private byte j;

        public MyStruct(byte a, byte b)
        {
            i = a;
            j = b;
        }

        public byte J
        {
            get { return j; }
            set { j = value; }
        }

        public byte I
        {
            get { return i; }
            set { i = value; }
        }
    }

[边城的刀声]

那如果你想控制它在“源”视图中的数据怎么办，也就是序列化的时候，可以通过PersistenceMode来设置，具体 的值楼主可以看下MSDN里的详细介绍

[PersistenceMode(PersistenceMode.InnerDefaultProperty)]
public MyStruct MyPro

结果

<MyPro I="1" J="2" />

这样易读多了