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DynamicObject.TryGetIndex Method

Provides the implementation for operations that get a value by index. Classes derived from the DynamicObject class can override this method to specify dynamic behavior for indexing operations.

Namespace:  System.Dynamic
Assemblies:   System.Dynamic.Runtime (in System.Dynamic.Runtime.dll)
  System.Core (in System.Core.dll)

abstract TryGetIndex : 
        binder:GetIndexBinder * 
        indexes:Object[] * 
        result:Object byref -> bool  
override TryGetIndex : 
        binder:GetIndexBinder * 
        indexes:Object[] * 
        result:Object byref -> bool

Parameters

binder
Type: System.Dynamic.GetIndexBinder

Provides information about the operation.

indexes
Type: System.Object[]

The indexes that are used in the operation. For example, for the sampleObject[3] operation in C# (sampleObject(3) in Visual Basic), where sampleObject is derived from the DynamicObject class, indexes[0] is equal to 3.

result
Type: System.Object

The result of the index operation.

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 run-time exception is thrown.)

Classes derived from the DynamicObject class can override this method to specify how getting a value by index 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 run-time exception is thrown.)

If this method is overridden, it is automatically invoked when you have an operation like sampleObject[3] in C# or sampleObject(3) in Visual Basic, where sampleObject is derived from the DynamicObject class.

Assume that you want to create an object in which properties can be accessed either by names such as Property0, Property1, and so on, or by index, so that, for example, sampleObject.Property0 is equivalent to sampleObject[0] in C# or sampleObject(0) in Visual Basic.

The following code example demonstrates the SampleDynamicObject class, which is derived from the DynamicObject class. The SampleDynamicObject class contains an object of the Dictionary<string, object> type (Dictionary(Of String, Object) in Visual Basic) to store the key-value pairs. SampleDynamicObject overrides the TrySetIndex and TryGetIndex methods to enable access by index. It overrides the TrySetMember and TryGetMember methods to enable access by property name.

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

.NET Framework

Supported in: 4.6, 4.5, 4

.NET Framework Client Profile

Supported in: 4

Portable Class Library

Supported in: Portable Class Library

Supported in: Windows Phone 8.1

Supported in: Windows Phone Silverlight 8.1

Supported in: Windows Phone Silverlight 8
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