"news.microsoft.com" <x@x.com> wrote in message
news:OPGhZG1XFHA.3876@TK2MSFTNGP10.phx.gbl...
> Hi,
> I am a new .NET programmer starting with the Visual C# 2005 Express Beta
> 2, trying to replicate a VCL component that I use. I am trying to handle
> a collection of classes within the component, this class has its own
> properties that are editable by the standard collection editor. To break
> down the problem as much as possible, I have the following code:
>
> namespace mycomps {
>
> public partial class testcomp : UserControl
> {
> public class itemcollection : List<item>
> {
> public itemcollection() : base() { }
> public itemcollection(IEnumerable<item> collection) :
> base(collection) { }
> }
> private itemcollection FItems;
> public testcomp()
> {
> FItems = new itemcollection();
> InitializeComponent();
> }
>
> [DesignerSerializationVisibility(DesignerSerializationVisibility.Content)]
> public itemcollection Items { get { return FItems; } }
> }
>
> [TypeConverter(typeof(item.converter))]
> public class item
> {
> private string FCaption;
> public item()
> {
> }
> public item(string caption)
> {
> FCaption = caption;
> }
> public class converter : TypeConverter
> {
> public override bool CanConvertTo(ITypeDescriptorContext context,
> Type destinationType)
> {
> if (destinationType ==
> typeof(System.ComponentModel.Design.Serialization.InstanceDescriptor))
> return true;
> return base.CanConvertTo(context, destinationType);
> }
> public override object ConvertTo(ITypeDescriptorContext context,
> System.Globalization.CultureInfo culture, object value, Type
> destinationType)
> {
> if (destinationType ==
> typeof(System.ComponentModel.Design.Serialization.InstanceDescriptor))
> {
> item value_item = (item)value;
> System.Reflection.ConstructorInfo ctor =
> typeof(item).GetConstructor(new Type[] { typeof(string) });
> return new
> System.ComponentModel.Design.Serialization.InstanceDescriptor(ctor, new
> object[] { value_item.FCaption });
> }
> return base.ConvertTo(context, culture, value,
> destinationType);
> }
> }
> public string Caption { get { return FCaption; } set { FCaption =
> value; } }
> }
>
> } // namespace mycomps
>
> When I place this component on a form, I can edit the Items property ok,
> adding new items and changing the Caption property. But when I hit ok and
> try to run it or look at the designer code I get the following in a
> message box:
>
> Code generation for property 'Items' failed. Error was: 'Unable to case
> object of type 'mycomps.item' to type 'mycomps.item'.'
>
> Thanks for any help that anyone can give,
>
> Steve
>