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VS 2015 [RESOLVED] New Expressions.ConstantExpression??-VBForums
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Thread: [RESOLVED] New Expressions.ConstantExpression??

  1. #1

    Thread Starter
    PowerPoster i00's Avatar
    Join Date
    Mar 2002
    1/2 way accross the galaxy.. and then some

    Resolved [RESOLVED] New Expressions.ConstantExpression??

    I want to delcare a new Expressions.ConstantExpression...

    I was hoping that there was just a constructor like:
    Public Sub New Expressions.ConstantExpression(Value As Object)
    So I could go:
    New Expressions.ConstantExpression("K")
    And get something like:
    Name:  Const.jpg
Views: 139
Size:  15.2 KB

    ...Now I know that you are probably wondering why I want to do this ... so ... basically I am wanting to replace expressions with the proper const values... for eg:
    VB.Net Code:
    1. Dim ExpressionWithProperConsts =
    2.     Query.Expression.Visit(Function(p As Expressions.MemberExpression)
    3.                                If p.Expression.NodeType = Expressions.ExpressionType.Constant Then
    4.                                    Dim Value = Expressions.Expression.Lambda(p).Compile.DynamicInvoke()
    5.                                    Return New Expressions.ConstantExpression(Value)
    6.                                Else
    7.                                    Return p
    8.                                End If
    9.                            End Function)
    ... And yes I have my reasons ... so please don't say why

    And before you ask.. the .Visit thing is an extension of mine that allows me to replace expressions within an expression tree... but it works basically the same way as any other standard visitor... Just a helper for me to replace parts of expressions easily.

    Thanks in advance,

  2. #2
    .NUT jmcilhinney's Avatar
    Join Date
    May 2005
    Sydney, Australia

    Re: New Expressions.ConstantExpression??

    Have you read the documentation for the ConstantExpression class? It states:
    Use the Constant factory methods to create a ConstantExpression.
    It provides a link to the documentation for those methods and it provides a code example.
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  3. #3

    Thread Starter
    PowerPoster i00's Avatar
    Join Date
    Mar 2002
    1/2 way accross the galaxy.. and then some

    Re: New Expressions.ConstantExpression??

    Whops ... missed that

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