Class NullValueSource<T>

Definition

Namespace: StardewUI.Framework.Sources
Assembly: StardewUI.dll

Value source that always provides a null/default value, and does not allow writing.

public class NullValueSource<T> : StardewUI.Framework.Sources.IValueSource<T>, 
    StardewUI.Framework.Sources.IValueSource

Type Parameters

T
The return type of the context property.

Inheritance
Object ⇦ NullValueSource<T>

Implements
IValueSource<T>, IValueSource

Remarks

Can be used in place of a real IValueSource<T> when no data is available, e.g. when a complex binding is attempted when a null value is at the root, and therefore the destination type cannot be determined.

Members

Fields

Name	Description
Instance	Immutable default instance of a NullValueSource<T>.

Properties

Name	Description
CanRead	Whether or not the source can be read from, i.e. if an attempt to get the Value should succeed.
CanWrite	Whether or not the source can be written back to, i.e. if an attempt to set the Value should succeed.
DisplayName	Descriptive name for the property, used primarily for debug views and log/exception messages.
Value
ValueType	The compile-time type of the value tracked by this source; the type parameter for IValueSource<T>.

Methods

Name	Description
Update(Boolean)	Checks if the value needs updating, and if so, updates Value to the latest.

Details

Fields

Instance

Immutable default instance of a NullValueSource<T>.

public static readonly StardewUI.Framework.Sources.NullValueSource<T> Instance;

Field Value

NullValueSource<T>

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Properties

CanRead

Whether or not the source can be read from, i.e. if an attempt to get the Value should succeed.

public bool CanRead { get; }

Property Value

Boolean

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CanWrite

Whether or not the source can be written back to, i.e. if an attempt to set the Value should succeed.

public bool CanWrite { get; }

Property Value

Boolean

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DisplayName

Descriptive name for the property, used primarily for debug views and log/exception messages.

public string DisplayName { get; }

Property Value

string

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Value

public T Value { get; set; }

Property Value

T

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ValueType

The compile-time type of the value tracked by this source; the type parameter for IValueSource<T>.

public System.Type ValueType { get; }

Property Value

Type

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Methods

Update(bool)

Checks if the value needs updating, and if so, updates Value to the latest.

public bool Update(bool force);

Parameters

force   Boolean
If true, forces the source to update its value even if it isn't considered dirty. This should never be used in a regular binding, but can be useful in sources that are intended for occasional or one-shot use such as event handler arguments.

Returns

Boolean

true if the Value was updated; false if it already held the most recent value.

Remarks

This method is called every frame, for every binding, and providing a correct return value is essential in order to avoid slowdowns due to unnecessary rebinds.

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