Public Overridable Function TryUnaryOperation ( _
    binder As UnaryOperationBinder, _
    <OutAttribute> ByRef result As Object _
) As Boolean

Dim instance As DynamicObject
Dim binder As UnaryOperationBinder
Dim result As Object
Dim returnValue As Boolean

returnValue = instance.TryUnaryOperation(binder, _
    result)

public virtual bool TryUnaryOperation(
    UnaryOperationBinder binder,
    out Object result
)

public:
virtual bool TryUnaryOperation(
    UnaryOperationBinder^ binder, 
    [OutAttribute] Object^% result
)

abstract TryUnaryOperation : 
        binder:UnaryOperationBinder * 
        result:Object byref -> bool 
override TryUnaryOperation : 
        binder:UnaryOperationBinder * 
        result:Object byref -> bool 

using System;
using System.Collections.Generic;
using System.Dynamic;
using System.Linq.Expressions;

// The class derived from DynamicObject.
public class DynamicNumber : DynamicObject
{
    // The inner dictionary to store field names and values.
    Dictionary<string, object> dictionary
        = new Dictionary<string, object>();

    // Get the property value.
    public override bool TryGetMember(
        GetMemberBinder binder, out object result)
    {
        return dictionary.TryGetValue(binder.Name, out result);
    }

    // Set the property value.
    public override bool TrySetMember(
        SetMemberBinder binder, object value)
    {
        dictionary[binder.Name] = value;
        return true;
    }

    // Perform the unary operation. 
    public override bool TryUnaryOperation(
        UnaryOperationBinder binder, out object result)
    {
        // The Textual property contains 
        // the name of the unary operation in addition 
        // to the textual representaion of the number.
        string resultTextual =
             binder.Operation + " " +
             dictionary["Textual"].ToString();
        int resultNumeric;

        // Determining what type of operation is being performed.
        switch (binder.Operation)
        {
            case ExpressionType.Negate:
                resultNumeric =
                     -(int)dictionary["Numeric"];
                break;
            default:
                // In case of any other unary operation,
                // print out the type of operation and return false,
                // which means that the language should determine 
                // what to do.
                // (Usually the language just throws an exception.)            
                Console.WriteLine(
                    binder.Operation +
                    ": This unary operation is not implemented");
                result = null;
                return false;
        }

        dynamic finalResult = new DynamicNumber();
        finalResult.Textual = resultTextual;
        finalResult.Numeric = resultNumeric;
        result = finalResult;
        return true;
    }
}
   
class Program
{
    static void Main(string[] args)
    {
        // Creating the first dynamic number.
        dynamic number = new DynamicNumber();

        // Creating properties and setting their values
        // for the dynamic number.
        // The TrySetMember method is called.
        number.Textual = "One";
        number.Numeric = 1;

        // Printing out properties. The TryGetMember method is called.
        Console.WriteLine(
            number.Textual + " " + number.Numeric);

        dynamic negativeNumber = new DynamicNumber();

        // Performing a mathematical negation.
        // TryUnaryOperation is called.
        negativeNumber = -number;

        Console.WriteLine(
            negativeNumber.Textual + " " + negativeNumber.Numeric);
       
        // The following statement produces a run-time exception
        // because the unary plus operation is not implemented.
        // negativeNumber = +number;
    }
}

// This code example produces the following output:

// One 1
// Negate One -1

Imports System.Linq.Expressions
Imports System.Dynamic

' The class derived from DynamicObject.
Public Class DynamicNumber
    Inherits DynamicObject

    ' The inner dictionary to store field names and values.
    Dim dictionary As New Dictionary(Of String, Object)

    ' Get the property value.
    Public Overrides Function TryGetMember(
        ByVal binder As System.Dynamic.GetMemberBinder, 
        ByRef result As Object) As Boolean

        Return dictionary.TryGetValue(binder.Name, result)

    End Function

    ' Set the property value.
    Public Overrides Function TrySetMember(
        ByVal binder As System.Dynamic.SetMemberBinder, 
        ByVal value As Object) As Boolean

        dictionary(binder.Name) = value
        Return True

    End Function

    ' Perform the unary operation. 
    Public Overrides Function TryUnaryOperation(
        ByVal binder As System.Dynamic.UnaryOperationBinder,
        ByRef result As Object) As Boolean

        ' The Textual property contains the name of the unary operation
        ' in addition to the textual representaion of the number.
        Dim resultTextual As String =
        binder.Operation.ToString() & " " &
        dictionary("Textual")
        Dim resultNumeric As Integer

        ' Determining what type of operation is being performed.
        Select Case binder.Operation
            Case ExpressionType.Negate
                resultNumeric = -CInt(dictionary("Numeric"))
            Case Else
                ' In case of any other unary operation,
                ' print out the type of operation and return false,
                ' which means that the language should determine 
                ' what to do.
                ' (Usually the language just throws an exception.)            
                Console.WriteLine(
                    binder.Operation.ToString() &
                    ": This unary operation is not implemented")
                result = Nothing
                Return False
        End Select

        Dim finalResult As Object = New DynamicNumber()
        finalResult.Textual = resultTextual
        finalResult.Numeric = resultNumeric
        result = finalResult
        Return True
    End Function    
End Class


Module Module1
    Sub Main()
        ' Creating the first dynamic number.
        Dim number As Object = New DynamicNumber()

        ' Creating properties and setting their values
        ' for the dynamic number.
        ' The TrySetMember method is called.
        number.Textual = "One"
        number.Numeric = 1

        ' Printing out properties. The TryGetMember method is called.
        Console.WriteLine(
            number.Textual & " " & number.Numeric)

        Dim negativeNumber As Object = New DynamicNumber()

        ' Performing a mathematical negation.
        ' The TryUnaryOperation is called.
        negativeNumber = -number

        Console.WriteLine(
            negativeNumber.Textual & " " & negativeNumber.Numeric)

        '// The following statement produces a run-time exception
        '// because the unary plus operation is not implemented.
        'negativeNumber = +number
    End Sub
End Module

' This code example produces the following output:

' One 1
' Negate One -1