DynamicObject::TrySetMember Method (SetMemberBinder^, Object^)

 
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Provides the implementation for operations that set member values. Classes derived from the DynamicObject class can override this method to specify dynamic behavior for operations such as setting a value for a property.

Namespace:   System.Dynamic
Assembly:  System.Core (in System.Core.dll)

public:
virtual bool TrySetMember(
	SetMemberBinder^ binder,
	Object^ value
)

Parameters

binder
Type: System.Dynamic::SetMemberBinder^

Provides information about the object that called the dynamic operation. The binder.Name property provides the name of the member to which the value is being assigned. For example, for the statement sampleObject.SampleProperty = "Test", where sampleObject is an instance of the class derived from the DynamicObject class, binder.Name returns "SampleProperty". The binder.IgnoreCase property specifies whether the member name is case-sensitive.

value
Type: System::Object^

The value to set to the member. For example, for sampleObject.SampleProperty = "Test", where sampleObject is an instance of the class derived from the DynamicObject class, the value is "Test".

Return Value

Type: System::Boolean

true if the operation is successful; otherwise, false. If this method returns false, the run-time binder of the language determines the behavior. (In most cases, a language-specific run-time exception is thrown.)

Classes derived from the DynamicObject class can override this method to specify how operations that set a value to a member should be performed for a dynamic object. When the method is not overridden, the run-time binder of the language determines the behavior. (In most cases, a language-specific run-time exception is thrown.)

This method is called when you have statements like sampleObject.SampleProperty = "Test", where sampleObject is an instance of the class that is derived from the DynamicObject class.

You can also add your own members to classes derived from the DynamicObject class. If your class defines properties and also overrides the TrySetMember method, the dynamic language runtime (DLR) first uses the language binder to look for a static definition of a property in the class. If there is no such property, the DLR calls the TrySetMember method.

Assume that you want to provide alternative syntax for accessing values in a dictionary, so that instead of writing sampleDictionary["Text"] = "Sample text" (sampleDictionary("Text") = "Sample text" in Visual Basic), you can write sampleDictionary.Text = "Sample text". Also, this syntax must be case-insensitive, so that sampleDictionary.Text is equivalent to sampleDictionary.text.

The following code example demonstrates the DynamicDictionary class, which is derived from the DynamicObject class. The DynamicDictionary class contains an object of the Dictionary<string, object> type (Dictionary(Of String, Object) in Visual Basic) to store the key-value pairs, and overrides the TrySetMember and TryGetMember methods to support the new syntax. It also provides a Count property, which shows how many dynamic properties the dictionary contains.

No code example is currently available or this language may not be supported.

Universal Windows Platform
Available since 8
.NET Framework
Available since 4.0
Portable Class Library
Supported in: portable .NET platforms
Silverlight
Available since 4.0
Windows Phone Silverlight
Available since 8.0
Windows Phone
Available since 8.1
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