Hi,

We are writing an application that will host a form's designer to the user in a windows application. We looked at some sample designer hosting application and we were able to get this running.

Now, for the standard windows controls (like Button, Textbox etc) we need to provide custom properties in the property window. We need to hide most of the properties available for this standard controls and include our own custom properties. Is there any sample that is available for customizing the properties of standard controls?

We tried creating a UserControl with the Designer Attribute referencing a type of another class derived from ControlDesigner. When we try to reference this class instance for propertygrid.SelectedObject, the application is throwing "Cannot cast Button_Properties to IDesigner". Any help will be appreciated.

Anandan

Hi,

You can do this by overriding PreFilterProperties or PostFilterProperties on the control designer. You can then remove the properties you need, or all of them, and then add the ones you need. You should be aware that by doing so some of the designer features might stop working as they rely on various properties being available on the control.

If your PreFilterProperties/PostFilterProperties method is not being called, you need to install aTypeDescriptorFilterService, which for FilterProperties, gets the IDesigner for the component, and if that designer is IDesignerFilter calls designer.PreFilterProperties(properties) and designer.PostFilterProperties(properties). Should also do the same for the other methods (FilterAttributes, FilterEvents,). I.e. something like this:

bool ITypeDescriptorFilterService.FilterProperties(IComponent component, IDictionary properties) {

if (component != null && properties != null) {

IDesigner designer = <get the designer>

if (designer is IDesignerFilter) {

((IDesignerFilter)designer).PreFilterProperties(properties);

((IDesignerFilter)designer).PostFilterProperties(properties);

}

}

return designer != null;

}

Martin

Hi,

You can do this by overriding PreFilterProperties or PostFilterProperties on the control designer. You can then remove the properties you need, or all of them, and then add the ones you need. You should be aware that by doing so some of the designer features might stop working as they rely on various properties being available on the control.

If your PreFilterProperties/PostFilterProperties method is not being called, you need to install aTypeDescriptorFilterService, which for FilterProperties, gets the IDesigner for the component, and if that designer is IDesignerFilter calls designer.PreFilterProperties(properties) and designer.PostFilterProperties(properties). Should also do the same for the other methods (FilterAttributes, FilterEvents,). I.e. something like this:

bool ITypeDescriptorFilterService.FilterProperties(IComponent component, IDictionary properties) {

if (component != null && properties != null) {

IDesigner designer = <get the designer>

if (designer is IDesignerFilter) {

((IDesignerFilter)designer).PreFilterProperties(properties);

((IDesignerFilter)designer).PostFilterProperties(properties);

}

}

return designer != null;

}

Martin

Thanks Martin.

We are able to trim out unwantedproperties using the method you mentioned above. But what we really need is to add some custom properties. We tried creating a seperate class derived from UserControl (pl. see my previous post) with our own properties.

When we try to use this against PropertyGrid.SelectedObject class (propertygrid.selectedobject = new myclass()), we are getting a cast error. The error message in the exception is "Unable to cast myclass to IDesigner".

We are not sure what we are missing. Any code sample for overriding standard windows controls (like Button, Textbox) with new properties will help us greatly.

Thanks

[ProvideProperty("YourPropertyName", typeof(IComponent))]
public class MyPropertyExtender : System.ComponentModel.Component, IExtenderProvider
{
public bool CanExtend(object extendee)
{
return (extendee is IComponent);
}

type GetYourPropertyName(IComponent component) { return values[compent];}

}

Online help for IExtenderProvider is available.

Hi,

You could also you PreFilterProperties to do something similar bycallingTypeDescriptor.CreateProperty.

properties["<your property>"] = TypeDescriptor.CreateProperty

Martin