propertyGrid实现选项（原创）

Draw Dorp-Down propertyGrid

[TypeConverter(typeof(backgroundRepeatConverter)),
            DescriptionAttribute("description"),
            CategoryAttribute("行为")]
            public string backgroundRepeat
            {
                get
                {
                        if(e.style.backgroundRepeat==null)return "";
                        return e.style.backgroundRepeat;
                
                }
                set
                {
                    e.style.backgroundRepeat=value;
                }
            }

public class backgroundRepeatConverter: StringConverter
        {  
            public override StandardValuesCollection
                GetStandardValues(ITypeDescriptorContext context) 
            {
                return new StandardValuesCollection(new string[]{"repeat", 
                                                                    "repeat-x", 
                                                                    "repeat-y",
                "no-repeat"});
            }
            public override bool GetStandardValuesSupported(
                ITypeDescriptorContext context) 
            {
                return true;
            }
            public override bool GetStandardValuesExclusive(
                ITypeDescriptorContext context) 
            {
                return true;
            }
        }