Question

I try binding generic collection listContact to propGrid but output does not match what I expected. I want listContact to be shown like ListBox in propGrid. How do I do it? Thank you.

class Contact
{
    public string Name { get; set; }
    public string Address { get; set; }
}

PropertyGrid propGrid = new PropertyGrid();
List<Contact> listContact   = new List<Contact>();

private void Form1_Load(object sender, EventArgs e)
{
    listContact.Clear();
    Contact newContact = null;

    newContact = new Contact();
    newContact.Name = "diana";
    newContact.Address = "en";
    listContact.Add(newContact);

    newContact = null;
    newContact = new Contact();
    newContact.Name = "maxim";
    newContact.Address = "cand";
    listContact.Add(newContact);

    propGrid.SelectedObject = listContact;
    this.Controls.Add(propGrid);
    propGrid.Dock = DockStyle.Fill;

}

Answer 1

You have to extend you class to use ExpandableObjectConverter. This makes the parseable happen.

See the below code. Just a fell examples. Pick the one you like the most.
The source used to code : MSDN

[TypeConverter(typeof(Contact))]
[DescriptionAttribute("Expand to see the spelling options for the application.")]
class Contact : ExpandableObjectConverter
{
    [DefaultValueAttribute("Contact Name")]
    public string Name { get; set; }
    public string Address { get; set; }

    public override bool CanConvertTo(ITypeDescriptorContext context, Type destinationType)
    {
        if (destinationType == typeof(Contact))
        {
            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.String) && value is Contact)
        {
            Contact contact = value as Contact;

            return string.Format("Name: {0} - Address: {1}", contact.Name, contact.Address);
        }
        return base.ConvertTo(context, culture, value, destinationType);
    }
}

[TypeConverter(typeof(Contact2))]
[DescriptionAttribute("Expand to see the spelling options for the application.")]
class Contact2 : ExpandableObjectConverter
{
    private Contact contato1;
    public Contact Contato1
    {
        get
        {
            return contato1;
        }
        set
        {
            contato1 = value;
        }
    }

    private Contact contato3;
    public Contact Contato3
    {
        get
        {
            return contato3;
        }
        set
        {
            contato3 = value;
        }
    }

    public Contact2()
    {
        this.contato1 = new Contact()
        {
            Address = "Add1",
            Name = "Name1"
        };
        this.contato3 = new Contact()
        {
            Address = "Add3",
            Name = "Name3"
        };
    }
}

public partial class Form2 : Form
{
    PropertiesList<Contact> listContact = new PropertiesList<Contact>();
    //List<Contact> listContact = new List<Contact>();

    public Form2()
    {
        InitializeComponent();
    }

    private void Form2_Load(object sender, EventArgs e)
    {
        listContact.Clear();
        Contact newContact = null;

        newContact = new Contact();
        newContact.Name = "diana";
        newContact.Address = "en";
        listContact.Add(newContact);

        newContact = null;
        newContact = new Contact();
        newContact.Name = "maxim";
        newContact.Address = "cand";
        listContact.Add(newContact);

        propGrid.AllowDrop = true;

        object[] itens = new object[2];
        itens[0] = listContact;
        itens[1] = newContact;
        propGrid.SelectedObject = listContact;
        this.Controls.Add(propGrid);
        propGrid.Dock = DockStyle.Fill;
    }
}

[TypeConverter(typeof(Contact))]
class PropertiesList<T> : ExpandableObjectConverter where T : Contact
{
    private List<T> innerList = new List<T>();

    public List<string> Names
    {
        get
        {
            List<string> valuesReturned = null;
            if (innerList.Count > 0)
            {
                valuesReturned = new List<string>();
                for (int i = 0; i < innerList.Count; i++)
                {
                    valuesReturned.Add(innerList[i].Name);
                }

            }
            return valuesReturned;
        }
    }

    public List<T> Item
    {
        get
        {
            List<T> valuesReturned = null;
            if (innerList.Count > 0)
            {
                valuesReturned = new List<T>();
                for (int i = 0; i < innerList.Count; i++)
                {
                    valuesReturned.Add(innerList[i]);
                }

            }
            return valuesReturned;
        }
    }

    public Color GetColors { get; set; }

    public Contact2 Contato22
    {
        get
        {
            return new Contact2();
        }
    }

    public override bool CanConvertTo(ITypeDescriptorContext context, Type destinationType)
    {
        if (destinationType == typeof(Contact))
        {
            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.String) && value is Contact)
        {
            Contact contact = value as Contact;

            return string.Format("Name: {0} - Address: {1}", contact.Name, contact.Address);
        }
        return base.ConvertTo(context, culture, value, destinationType);
    }

    #region Simulate List
    public void Add(T item)
    {
        innerList.Add(item);
    }

    public void Clear()
    {
        innerList.Clear();
    }
    #endregion
}