' Add the following directive to your file:
' Imports System.Linq.Expressions  

' This parameter expression represents a variable that will hold the array.
Dim arrayExpr As ParameterExpression = Expression.Parameter(GetType(Integer()), "Array")

' This parameter expression represents an array index.
' For multidimensional arrays, you can define several indexes. 
Dim indexExpr As ParameterExpression = Expression.Parameter(GetType(Integer), "Index")

' This parameter represents the value that will be added to a corresponding array element.
Dim valueExpr As ParameterExpression = Expression.Parameter(GetType(Integer), "Value")

' This expression represents an array access operation.
' It can be used for assigning to, or reading from, an array element.
Dim arrayAccessExpr As Expression = Expression.ArrayAccess(
    arrayExpr,
    indexExpr
)

' This lambda expression assigns a value provided to it to a specified array element.
' The array, the index of the array element, and the value to be added to the element
' are parameters of the lambda expression.
Dim lambdaExpr As Expression(Of Func(Of Integer(), Integer, Integer, Integer)) =
    Expression.Lambda(Of Func(Of Integer(), Integer, Integer, Integer))(
        Expression.Assign(arrayAccessExpr, Expression.Add(arrayAccessExpr, valueExpr)),
    arrayExpr,
    indexExpr,
    valueExpr
  )

' Print expressions.
Console.WriteLine("Array Access Expression:")
Console.WriteLine(arrayAccessExpr.ToString())

Console.WriteLine("Lambda Expression:")
Console.WriteLine(lambdaExpr.ToString())

Console.WriteLine("The result of executing the lambda expression:")

' The following statement first creates an expression tree,
' then compiles it, and then executes it.
' Parameters passed to the Invoke method are passed to the lambda expression.
Console.WriteLine(lambdaExpr.Compile().Invoke(New Integer() {10, 20, 30}, 0, 5))