Class LazyExpressionFieldDescriptor<TValue>

Definition

Namespace: StardewUI.Framework.Descriptors
Assembly: StardewUI.dll

Implementation of a field descriptor that supports a transition between two inner descriptor types.

public class LazyExpressionFieldDescriptor<TValue> : 
    StardewUI.Framework.Descriptors.IPropertyDescriptor<TValue>, 
    StardewUI.Framework.Descriptors.IPropertyDescriptor, 
    StardewUI.Framework.Descriptors.IMemberDescriptor

Type Parameters

TValue
The field's value type.

Inheritance
Object ⇦ LazyExpressionFieldDescriptor<TValue>

Implements
IPropertyDescriptor<TValue>, IPropertyDescriptor, IMemberDescriptor

Remarks

Designed to initially use a "slow" descriptor that is poorly optimized for access times, but is available immediately, and then transition to a "fast" descriptor that is created asynchronously and slowly, but is better optimized for frequent access.

Members

Constructors

Name	Description
LazyExpressionFieldDescriptor<TValue>(IPropertyDescriptor<TValue>, Task<IPropertyDescriptor<TValue>>)	Initializes a new LazyExpressionFieldDescriptor<TValue> instance.

Properties

Name	Description
CanRead	Whether or not the property is readable, i.e. has a public getter.
CanWrite	Whether or not the property is writable, i.e. has a public setter.
DeclaringType	The type on which the member is declared.
IsAutoProperty	Whether or not the property is likely auto-implemented.
IsField	Whether or not the underlying member is a field, rather than a real property.
Name	The member name.
ValueType	The property's value type.

Methods

Name	Description
GetValue(Object)	Reads the current property value.
SetValue(Object, TValue)	Writes a new property value.

Details

Constructors

LazyExpressionFieldDescriptor<TValue>(IPropertyDescriptor<TValue>, Task<IPropertyDescriptor<TValue>>)

Initializes a new LazyExpressionFieldDescriptor<TValue> instance.

public LazyExpressionFieldDescriptor<TValue>(StardewUI.Framework.Descriptors.IPropertyDescriptor<TValue> slowDescriptor, System.Threading.Tasks.Task<StardewUI.Framework.Descriptors.IPropertyDescriptor<TValue>> fastDescriptorTask);

Parameters

slowDescriptor   IPropertyDescriptor<TValue>
The slower but immediately-available descriptor to use initially; typically an instance of ReflectionFieldDescriptor<TValue>.

fastDescriptorTask   Task<IPropertyDescriptor<TValue>>
The faster, deferred descriptor to use once available; typically an instance of ExpressionFieldDescriptor<T, TValue>.

---

Properties

CanRead

Whether or not the property is readable, i.e. has a public getter.

public bool CanRead { get; }

Property Value

Boolean

Remarks

For fields, always returns true.

---

CanWrite

Whether or not the property is writable, i.e. has a public setter.

public bool CanWrite { get; }

Property Value

Boolean

---

DeclaringType

The type on which the member is declared.

public System.Type DeclaringType { get; }

Property Value

Type

---

IsAutoProperty

Whether or not the property is likely auto-implemented.

public bool IsAutoProperty { get; }

Property Value

Boolean

Remarks

Auto-property detection is heuristic, relying on the method's IL instructions and the name of its backing field. This can often be interpreted as a signal that the property won't receive property-change notifications, since to do so (whether explicitly or via some weaver/source generator) requires an implementation that is different from the auto-generated getter and setter.

Caveats: This only works as a negative signal (a value of false does not prove that the property will receive notifications, even if the declaring type implements INotifyPropertyChanged), and is somewhat fuzzy even as a negative signal; it is theoretically possible for a source generator or IL weaver to leave behind all the markers of an auto property and still emit notifications, although no known libraries actually do so.

---

IsField

Whether or not the underlying member is a field, rather than a real property.

public bool IsField { get; }

Property Value

Boolean

Remarks

For binding convenience, fields and properties are both called "properties" for descriptors, as the external access pattern is the same; however, mutable fields can never reliably emit property-change notifications regardless of whether the declaring type implements INotifyPropertyChanged, so this is usually used to emit some warning.

---

Name

The member name.

public string Name { get; }

Property Value

string

---

ValueType

The property's value type.

public System.Type ValueType { get; }

Property Value

Type

---

Methods

GetValue(Object)

Reads the current property value.

public TValue GetValue(System.Object source);

Parameters

source   Object
An instance of the property's DeclaringType.

Returns

TValue

---

SetValue(Object, TValue)

Writes a new property value.

public void SetValue(System.Object target, TValue value);

Parameters

target   Object
An instance of the property's DeclaringType.

value   TValue
The new property value.

---