Custom Control Design-Time SiteMap Provider Error

Hi

I have created a custom control from scratch and it works fine as in you can build the project that uses it and it works fine at runtime. Problem is when you go to design view the control shows an error in the place of where the control should be rendered.

Error: '<SomeValue>' Could not be set to '<SomeProperty>'

This shows up on all my custom set properties. These properties are created as basic as possible. I can give the properties values in Source view and run the app just fine. I can even add a Onclick event. If I don't set any custom properties the control will render fine in Design view. It's only when I set a value to a custom property.

Property Code Example:

public string Text
        {
            get
            {
                string ret = "";
                object obj = ViewState["Text"];
                if (obj != null)
                {
                    ret = obj.ToString();
                }
                return ret;
            }
            set
            {
                ViewState["Text"] = value;
            }
        }

I've even removed the Category and Description tags with no difference.

I don't know if what I said makes sens, but I hope it

Dino Esposito

MSDN Magazine December 2003

Hi,

I created an Extender which has a custom property that drills down a list XML elements from an xml file, where users can select xml elements during design-time. This works perfectly fine. However, my code only has a hardcoded xml filename (source of the xml elements list) and I need to change this by maxing the xml file user-specified.

What I did is that I created another control (panel) which has a custom property that when clicked (through the ellipsis), it will allow a developer to select the xml file which is supposed to be the source xml file that the Extenders shall use. The filedialog from custom panel's property works perfectly fine.

However, my problem now is that when I drag-drop my Extender, I cannot find a way to get the property value of the custom Panel Control which contains the xml filename. I tried creating a static variable which I thought the custom controls can share but VS2010 is breaking.

Please take note that my problem is on Design-time, asp.net.

Appreciate any help. Thanks a lot.

Dhon Nuevo.

Let's say that I've got one custom webcontrol called MyControl.

[ParseChildren(true)]
public partial class MyControl: WebControl {
[DesignerSerializationVisibility(DesignerSerializationVisibility.Content)]
[PersistenceMode(PersistenceMode.InnerProperty)]
public IComplex Complex { get; set; }
}

The control is a very simple control but it holds an instance of a complex type that is accessable through a property. The property has the propertytype IComplex

public interface IComplex {
string Name { get; set; }
List<IComplex> Children {get;}
}

Let's say that I am able to pick one of several different types of object that derives from IComplex in design-time and assign it to the controls property "Complex" property.

Naturally I would like to persist this information to the HTML-View in a user-friendly way.

Because we don't know what type the user has picked there is no way to instansiate the type if we don't persist the name of that type. The Type could also contain more properties than the Interface the controls property is refering.

<cc1:MyControl id="MyControl1" runat="server">
<Complex> <!-

In this article, Paul Ballard shows how you can provide data binding support for your custom collections to enable sorting, searching, and editing in as simple a manner as possible. In addition, he shows how to make all of these features available in the Windows and Web Forms Designers, just like an ADO.NET DataSet.

Paul Ballard

MSDN Magazine August 2005