// Shadow control properties with design time properties.
protected override void PreFilterProperties(IDictionary properties)
{
    // Call the base class method first.
    base.PreFilterProperties(properties);

    // Add the ConnectionString property to the property grid.
    PropertyDescriptor property =
        (PropertyDescriptor)properties["ConnectionString"];
    Attribute[] attributes = new Attribute[]
    {
        new BrowsableAttribute(true),
        new ReadOnlyAttribute(true)
    };
    properties["ConnectionString"] = TypeDescriptor.CreateProperty(
        GetType(), property, attributes);
}

// Create a control and bind it to the ExampleAccessDataSourceDesigner.
[AspNetHostingPermission(System.Security.Permissions.SecurityAction.Demand,
    Level = AspNetHostingPermissionLevel.Minimal)]
[AspNetHostingPermission(System.Security.Permissions.SecurityAction.InheritanceDemand,
    Level = AspNetHostingPermissionLevel.Minimal)]
[Designer(typeof(CustomControls.Design.ExampleAccessDataSourceDesigner))]
public class ExampleAccessDataSource : AccessDataSource
{
    // Does nothing extra
}