V-Light V-Light - 1 year ago 80
Vb.net Question

Get current enumerator (iterator ?) in LINQ query. Like a current index in for loops

Is that possible to get current Enumerator (...or iterator? Don't know which tern is the correct one) in a LINQ query ?

For example, I try to create a XML output (via LINQ to XML) of all currently loaded assemblies.

Dim xmldoc As XDocument = New XDocument(
New XElement("Types",
Assembly.GetExecutingAssembly().GetReferencedAssemblies() _
.Select(Function(name) Assembly.Load(name)) _
.SelectMany(Function(assembly) assembly.GetTypes()) _
.Select(Function(type) New XElement("Type", type.FullName))))


Tho output looks like this.

<Types>
<Type>System.Object</Type>
<Type>FXAssembly</Type>
<Type>ThisAssembly</Type>
<Type>AssemblyRef</Type>
<Type>System.Runtime.Serialization.ISerializable</Type>
<Type>System.Runtime.InteropServices._Exception</Type>
.....
</Types>


is it possible to somehow get current "index" (counter?) from LINQ's Selects? I would like to use it in XML

<Types>
<Type ID="1">System.Object</Type>
<Type ID="2">FXAssembly</Type>
<Type ID="3">ThisAssembly</Type>
<Type ID="4">AssemblyRef</Type>
<Type ID="or-some-other-unique-id-#5">System.Runtime.Serialization.ISerializable</Type>
.....
</Types>

Answer Source

Yup - you just need to use the overload of Select which takes a Func<TSource, int, TResult>. So in C# it would be something like:

XDocument doc = new XDocument(new XElement("Types",
    Assembly.GetExecutingAssembly().GetReferencedAssemblies()
        .Select(name => Assembly.Load(name))
        .SelectMany(assembly => assembly.GetTypes())
        .Select((type, index) => new XElement("Type",
                                              new XAttribute("ID", index + 1), 
                                              type.FullName))));

Sorry it's not in VB, but it's more likely to work this way - hopefully you can work out the translation :)

Recommended from our users: Dynamic Network Monitoring from WhatsUp Gold from IPSwitch. Free Download