Question

我正在尝试为一个拥有事件系统的游戏编写一个编辑器，其中包含事件的基类，然后是另一个实际执行所有操作的类。

因此，我有一个显示在PropertyGrid中的BaseEvent列表，并且作为列表，打开了集合编辑器。我准备了一个TypeConverter，所以我有一个包含所有派生类的下拉列表，显示在“Value”属性中。

一切正常，派生类的属性显示为“Value”的子项，但是一旦我想从BaseEvent显示属性，“Value”属性就会消失，子节点会出现在根节点，所以我就是无法更改活动的类型。

有没有办法让“Value”属性与BaseEvent属性同时出现？

//This allows to get a dropdown for the derived classes
public class EventTypeConverter : ExpandableObjectConverter
{
    public override StandardValuesCollection GetStandardValues(ITypeDescriptorContext context)
    {
        return new StandardValuesCollection(GetAvailableTypes());
    }

    /*
    ...
    */
}

[TypeConverter(typeof(EventTypeConverter))]
public abstract class BaseEvent
{
    public bool BaseProperty; //{ get; set; } If I set this as a property, "Value" disappears
}

public class SomeEvent : BaseEvent
{
    public bool SomeOtherProperty { get; set; }
}

//The object selected in the PropertyGrid is of this type
public class EventManager
{
    public List<BaseEvent> Events { get; set; } //The list that opens the collection editor
}

Answer 1

最后我找到了解决这个问题的方法：通过GetProperties方法和自定义PropertyDescriptor：

public override PropertyDescriptorCollection GetProperties(ITypeDescriptorContext context, object value, Attribute[] attributes)
{
    //Get the base collection of properties
    PropertyDescriptorCollection basePdc = base.GetProperties(context, value, attributes);

    //Create a modifiable copy
    PropertyDescriptorCollection pdc = new PropertyDesctiptorCollection(null);
    foreach (PropertyDescriptor descriptor in basePdc)
        pdc.Add(descriptor);

    //Probably redundant check to see if the value is of a correct type
    if (value is BaseEvent)
        pdc.Add(new FieldDescriptor(typeof(BaseEvent), "BaseProperty"));
    return pdc;
}

public class FieldDescriptor : SimplePropertyDescriptor
{
    //Saves the information of the field we add
    FieldInfo field;

    public FieldDescriptor(Type componentType, string propertyName)
        : base(componentType, propertyName, componentType.GetField(propertyName, BindingFlags.Instance | BindingFlags.NonPublic).FieldType)
    {
        field = componentType.GetField(propertyName, BindingFlags.Instance | BindingFlags.NonPublic);
    }

    public override object GetValue(object component)
    {
        return field.GetValue(component);
    }

    public override void SetValue(object component, object value)
    {
        field.SetValue(component, value);
    }
}

如何在PropertyGrid中显示对象的“Value”属性

1 个答案: