protected object EditValueHelper(ITypeDescriptorContext context,
IServiceProvider provider, object value,
FlagsEditorControl.ValueExclusionCheck valueCheck)
{
// if value is not an enum than we can not edit it
if (!(value is Enum))
throw new Exception("Value is not supported");
// try to figure out that is this a Flags enum or not ?
Type enumType = value.GetType();
object[] attributes = enumType.GetCustomAttributes(typeof(FlagsAttribute), true);
if (attributes.Length == 0)
throw new Exception("Editing enum hasn't got Flags attribute");
// check the underlying type
Type type = Enum.GetUnderlyingType(value.GetType());
if (type != typeof(byte) && type != typeof(sbyte)
&& type != typeof(short) && type != typeof(ushort)
&& type != typeof(int) && type != typeof(uint))
return value;
if (provider != null)
{
// use windows forms editor service to show drop down
IWindowsFormsEditorService edSvc = provider.GetService(
typeof(IWindowsFormsEditorService))
as IWindowsFormsEditorService;
if (edSvc == null)
return value;
//if (editor == null)
// editor = new FlagsEditorControl(this);
// prepare list
editor.Begin(edSvc, value, valueCheck);
// show drop down now
edSvc.DropDownControl(editor);
// now we take the result
value = editor.Value;
// reset editor
editor.End();
}
return Convert.ChangeType(value, type);
}
public FlagsEditor()
{
editor = new FlagsEditorControl(this);
}