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11-10-2019 - |
题
有没有一种方法可以使“可浏览”属性有条件,因此适用它的属性有时会出现在属性页面中,有时不会出现?
谢谢 :)
解决方案
没有简单的方法。
您可以通过实现IcustomTypedScriptor来解决此问题。这是一篇很好的文章 实现IcustomTypedScriptor.
其他提示
我不确定这适用于您的情况,但是您可以通过调用以下功能来调整运行时的“可浏览”装饰。
/// <summary>
/// Set the Browsable property.
/// NOTE: Be sure to decorate the property with [Browsable(true)]
/// </summary>
/// <param name="PropertyName">Name of the variable</param>
/// <param name="bIsBrowsable">Browsable Value</param>
private void setBrowsableProperty(string strPropertyName, bool bIsBrowsable)
{
// Get the Descriptor's Properties
PropertyDescriptor theDescriptor = TypeDescriptor.GetProperties(this.GetType())[strPropertyName];
// Get the Descriptor's "Browsable" Attribute
BrowsableAttribute theDescriptorBrowsableAttribute = (BrowsableAttribute)theDescriptor.Attributes[typeof(BrowsableAttribute)];
FieldInfo isBrowsable = theDescriptorBrowsableAttribute.GetType().GetField("Browsable", BindingFlags.IgnoreCase | BindingFlags.NonPublic | BindingFlags.Instance);
// Set the Descriptor's "Browsable" Attribute
isBrowsable.SetValue(theDescriptorBrowsableAttribute, bIsBrowsable);
}
您可以通过提供自定义类型模型来做到这一点;在 最简单 级别,您可以提供自定义 TypeDescriptor
对于您的类型 ExpandableObjectConverter
, ,并简单地包括/排除在一时兴起的给定属性 - 但这仅适用于 PropertyGrid
- 属性页面使用。一种更复杂的方法是使用 ICustomTypeDescriptor
/ TypeDescriptionProvider
- 然后可以在内部工作 DataGridView
作为对 @neoikon上述答案的改进,为了避免评论中提到的例外,这是一个使用仿制药来获取类型的版本:
/// <summary>
/// Set the Browsable property.
/// NOTE: Be sure to decorate the property with [Browsable(true)]
/// </summary>
/// <param name="PropertyName">Name of the variable</param>
/// <param name="bIsBrowsable">Browsable Value</param>
private void SetBrowsableProperty<T>(string strPropertyName, bool bIsBrowsable)
{
// Get the Descriptor's Properties
PropertyDescriptor theDescriptor = TypeDescriptor.GetProperties(typeof(T))[strPropertyName];
// Get the Descriptor's "Browsable" Attribute
BrowsableAttribute theDescriptorBrowsableAttribute = (BrowsableAttribute)theDescriptor.Attributes[typeof(BrowsableAttribute)];
FieldInfo isBrowsable = theDescriptorBrowsableAttribute.GetType().GetField("Browsable", BindingFlags.IgnoreCase | BindingFlags.NonPublic | BindingFlags.Instance);
// Set the Descriptor's "Browsable" Attribute
isBrowsable.SetValue(theDescriptorBrowsableAttribute, bIsBrowsable);
}
然后,您还可以添加一个使用实例的版本:
/// <summary>
/// Set the Browsable property.
/// NOTE: Be sure to decorate the property with [Browsable(true)]
/// </summary>
/// <param name="obj">An instance of the object whose property should be modified.</param>
/// <param name="PropertyName">Name of the variable</param>
/// <param name="bIsBrowsable">Browsable Value</param>
private void SetBrowsableProperty<T>(T obj, string strPropertyName, bool bIsBrowsable)
{
SetBrowsableProperty<T>(strPropertyName, bIsBrowsable);
}
用法:
class Foo
{
[Browsable(false)]
public string Bar { get; set; }
}
void Example()
{
SetBrowsableProperty<Foo>("Bar", true);
Foo foo = new Foo();
SetBrowsableProperty(foo, "Bar", false);
}
我遇到了这一点,以寻找一种方式来声明某些成员在Intellisense中可见或隐藏,并能够将其更改为所有需要在编译时间内隐藏的内容。我无法判断您是否正在寻找,但是我找到了我的问题的答案……认为分享不会受到伤害。
我设置了有条件的汇编符号(在项目属性的“构建选项卡”中找到)IS_VIS(如果您希望某些成员显示,则为true,如果您想隐藏它们,则为false),然后:
#if IS_VIS
public const System.ComponentModel.EditorBrowsableState isVis =
ComponentModel.EditorBrowsableState.Always;
#else
public const System.ComponentModel.EditorBrowsableState isVis =
ComponentModel.EditorBrowsableState.Never;
#endif
然后,您在属性中引用ISVIS变量:
[EditorBrowsable(isVis)]
public string myMethod...
我在VB中做到了这一点,然后匆匆转换为C#。如果某事不正确,请告诉我。
约翰·卡明斯(John Cummings)的解决方案基本上对我有用,但由于他引入了仿制药(虽然这很明智),因此存在以下两个问题:
1-版本 SetBrowsableProperty<T>(T obj, string strPropertyName, bool bIsBrowsable)
当集合作为参数OBJ传递时,将失败,因为在这种情况下,T将是IEnumerable(例如列表,数组等)的实现,而不是实际打算的集合的类型。
2-它也允许传递原始类型,在这种情况下这是毫无意义的,几乎总是会失败。
完整的修订解决方案:
因此,这是解决这些问题并为我工作的修订解决方案:(我略微重命名了方法和变量)
首先要执行更改可浏览属性值的主要工作:
/// <summary>
/// Sets the Browsable attribute value of a property of a non premitive type.
/// NOTE: The class property must be decorated with [Browsable(...)] attribute.
/// </summary>
/// <param name="type">The type that contains the property, of which the Browsable attribute value needs to be changed</param>
/// <param name="propertyName">Name of the type property, of which the Browsable attribute value needs to be changed</param>
/// <param name="isBrowsable">The new Browsable value</param>
public static void SetBrowsableAttributeOfAProperty(Type type, string propertyName, bool isBrowsable)
{
//Validate type - disallow primitive types (this will eliminate problem-2 as mentioned above)
if (type.IsEnum || BuiltInTypes.Contains(type))
throw new Exception($"The type '{type.Name}' is not supported");
var objPropertyInfo = TypeDescriptor.GetProperties(type);
// Get the Descriptor's Properties
PropertyDescriptor theDescriptor = objPropertyInfo[propertyName];
if (theDescriptor == null)
throw new Exception($"The property '{propertyName}' is not found in the Type '{type}'");
// Get the Descriptor's "Browsable" Attribute
BrowsableAttribute theDescriptorBrowsableAttribute = (BrowsableAttribute)theDescriptor.Attributes[typeof(BrowsableAttribute)];
FieldInfo browsablility = theDescriptorBrowsableAttribute.GetType().GetField("Browsable", BindingFlags.IgnoreCase | BindingFlags.NonPublic | BindingFlags.Instance);
// Set the Descriptor's "Browsable" Attribute
browsablility.SetValue(theDescriptorBrowsableAttribute, isBrowsable);
}
现在,约翰·卡明斯(John Cummings)的解决方案中提出的变体 <T>
:
public static void SetBrowsableAttributeOfAProperty<T>(string propertyName, bool isBrowsable)
{
SetBrowsableAttributeOfAProperty(typeof(T), propertyName, isBrowsable);
}
现在有问题的超载。 1,但是以下修改现在可以处理:
/// <summary>
/// Sets the Browsable attribute value of a property of a non premitive type.
/// NOTE: The class property must be decorated with [Browsable(...)] attribute.
/// </summary>
/// <param name="obj">An instance of the type that contains the property, of which the Browsable attribute value needs to be changed.</param>
/// <param name="propertyName">Name of the type property, of which the Browsable attribute value needs to be changed</param>
/// <param name="isBrowsable">Browsable Value</param>
public static void SetBrowsableAttributeOfAProperty<T>(T obj, string propertyName, bool isBrowsable)
{
if (typeof(T).GetInterface("IEnumerable") != null && typeof(T) != typeof(string)) //String type needs to be filtered out as String also implements IEnumerable<char> but its not a normal collection rather a primitive type
{
//Get the element type of the IEnumerable collection
Type objType = obj.GetType().GetGenericArguments()?.FirstOrDefault(); //when T is a collection that implements IEnumerable except Array
if (objType == null) objType = obj.GetType().GetElementType(); //when T is an Array
SetBrowsableAttributeOfAProperty(objType, propertyName, isBrowsable);
}
else
SetBrowsableAttributeOfAProperty(typeof(T), propertyName, isBrowsable);
这是实用程序功能,以获取所有C#系统内置(原始)类型:
public static List<Type> BuiltInTypes
{
get
{
if (builtInTypes == null)
builtInTypes = Enum.GetValues(typeof(TypeCode)).Cast<TypeCode>().Select(t => Type.GetType("System." + Enum.GetName(typeof(TypeCode), t)))
.ToList();
return builtInTypes;
}
}
用法:
class Foo
{
[Browsable(false)]
public string Bar { get; set; }
}
void Example()
{
SetBrowsableAttributeOfAProperty<Foo>("Bar", true); //works
Foo foo = new Foo();
SetBrowsableAttributeOfAProperty(foo, "Bar", false); //works
List<Foo> foos = new List<Foo> { foo, new Foo { Bar = "item2" } };
SetBrowsableAttributeOfAProperty(foos, "Bar", true); //works now, whereas it would crash with an exception in John Cummings's solution
}