RoutedCommand 源码中构造器赋值的一个疑问？
0
悬赏园豆：20
[已解决问题]
解决于 2019-10-17 17:02
RoutedCommand 位于 System.Windows.Input 命名空间下，唯一继承自 ICommand，
其构造方法为
/// <summary>Initializes a new instance of the <see cref="T:System.Windows.Input.RoutedCommand" /> class.</summary>
public RoutedCommand()
{
this._name = string.Empty;
this._ownerType = (Type) null;
this._inputGestureCollection = (InputGestureCollection) null;
}
/// <summary>Initializes a new instance of the <see cref="T:System.Windows.Input.RoutedCommand" /> class with the specified name and owner type.</summary>
/// <param name="name">Declared name for serialization.</param>
/// <param name="ownerType">The type which is registering the command.</param>
/// <exception cref="T:System.ArgumentNullException">
/// <paramref name="name" /> is <see langword="null" />.</exception>
/// <exception cref="T:System.ArgumentException">the length of <paramref name="name" /> is zero.</exception>
/// <exception cref="T:System.ArgumentException">
/// <paramref name="ownerType" /> is <see langword="null" />.</exception>
public RoutedCommand(string name, Type ownerType)
: this(name, ownerType, (InputGestureCollection) null)
{
}this._inputGestureCollection = (InputGestureCollection) null;
为什么 赋值 null 还需要给它强制转换成 InputGestrueCollection 类型呢？ 避免装拆箱，影响性能？
最佳答案
0
#region Constructors
/// <summary>
/// Default Constructor - needed to allow markup creation
/// </summary>
public RoutedCommand()
{
_name = String.Empty;
_ownerType = null;
_inputGestureCollection = null;
}
/// <summary>
/// RoutedCommand Constructor with Name and OwnerType
/// </summary>
/// <param name="name">Declared Name of the RoutedCommand for Serialization</param>
/// <param name="ownerType">Type that is registering the property</param>
public RoutedCommand(string name, Type ownerType) : this(name, ownerType, null)
{
}
/// <summary>
/// RoutedCommand Constructor with Name and OwnerType
/// </summary>
/// <param name="name">Declared Name of the RoutedCommand for Serialization</param>
/// <param name="ownerType">Type that is registering the property</param>
/// <param name="inputGestures">Default Input Gestures associated</param>
public RoutedCommand(string name, Type ownerType, InputGestureCollection inputGestures)
{
if (name == null)
{
throw new ArgumentNullException("name");
}
if (name.Length == 0)
{
throw new ArgumentException(SR.Get(SRID.StringEmpty), "name");
}
if (ownerType == null)
{
throw new ArgumentNullException("ownerType");
}
_name = name;
_ownerType = ownerType;
_inputGestureCollection = inputGestures;
}
/// <summary>
/// RoutedCommand Constructor with Name and OwnerType and command identifier.
/// </summary>
/// <param name="name">Declared Name of the RoutedCommand for Serialization</param>
/// <param name="ownerType">Type that is registering the property</param>
/// <param name="commandId">Byte identifier for the command assigned by the owning type</param>
internal RoutedCommand(string name, Type ownerType, byte commandId) : this(name, ownerType, null)
{
_commandId = commandId;
}
#endregion我这边.NET4.8源码显示和你的不一样啊
收获园豆：20
应该是 Resharper 自己反编译后处理过的，不是源码的问题。O(∩_∩)O哈哈~
@BUTTERAPPLE: 应该是的
