creating expressions dynamically?

Is there an equivalent function in VB to eval() in javascript
I vaugley rememebr being able to use eval() to build expressions on the fly.

example:

for i = 0 to arSeg.length -1
   for j = 1 to 4
        if instr(arSeg(i),j)<>0 then
          result = eval(seg&j) ' result should be the value of variable seg1 through seg4
        end if
    next j
next i

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creating expressions dynamically?

Raj Chidipudi
may be this one could be what you're looking for <a href="http://msdn.microsoft.com/msdnmag/issues/02/09/CuttingEdge/default.aspx"> Using an Eval Function in Web Services</a>
Gisela
Thanx Jacob,

Found this:
Although I'm not sure I understand it yet.

'You can use the CallByName VB methode of the
'Microsoft.VisualBasic.Interaction class.

'Or you can create your own function

Public Function MyCallByName(ByVal O As Object, ByVal functionName As
String, ByVal Parameters() As Object) As Object
Try
Dim T As Type
Dim MI As MethodInfo
Dim ParamTypes(Parameters.Length - 1) As Type
Dim i As Integer

For i = 0 To Parameters.Length - 1
ParamTypes(i) = Parameters(i).GetType
Next i

T = O.GetType
MI = T.GetMethod(functionName, ParamTypes)

Return MI.Invoke(O, Parameters)

MI = Nothing
T = Nothing
Catch
Return Nothing
End Try
End Function

'The first parameter is the object or the module where the function is
'implemented.

'For exemple, you can use the functions like that :

Dim S As String

S = ""
S = S.Concat("Essai", " Toto")
Debug.WriteLine(S)

S = ""
S = CType(CallByName(S, "Concat", CallType.Method, New Object() {"Essai", "
Toto"}), String)
Debug.WriteLine(S)

S = ""
S = CType(MyCallByName(S, "Concat", New Object() {"Essai", " Toto"}),
String)
Debug.WriteLine(S)

we'll see how it pans out.
Todd
Grouchypb
Unfortunately, there is no Eval equivalent in .NET. I have a very, very vague recollection of someone putting out a library that did some basic forms of evaluation, but I can't recall where I saw it... Perhaps some aggressive searching with google or at www.dotnet247.com will help bring it to light... Sorry can't be of more help.
Googhum
Yes I don't know of any Eval in .Net but I love utilizing the System.Reflection namspace (which is what some of the code above uses) to create types or call methods via a string name. Of course the Reflection namespace is much more powerful than just that.
creating expressions dynamically?

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creating expressions dynamically?

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creating expressions dynamically?

creating expressions dynamically?

Raj Chidipudi

Gisela

Grouchypb

Googhum