[CodeGen/Roslyn] Turn a code compile unit to VB.Net code

[Merrion]

When working with Roslyn and Code Gen it is useful to be able to visualise the code graph you have built as raw VB.Net code (since most of us are accustomed to thinking in code).

This snippet turns any code compile unit into its VB.Net code:

    ''' <summary>
    ''' Turn whatever code compile unit is passed in to VB.Net code in a multi-line string
    ''' </summary>
    ''' <param name="codeUnitToShow">
    ''' The program graph (partial or complete) to turn into VB code
    ''' </param>
    ''' <returns></returns>
    Public Shared Function ToVBCodeString(ByVal codeUnitToShow As CodeCompileUnit) As String

        Using provider As New VBCodeProvider
            'Visual Basic specific initialisation
            Dim vbNetOptions As New CodeDom.Compiler.CodeGeneratorOptions()
            vbNetOptions.BlankLinesBetweenMembers = True

            Dim sbRet As New System.Text.StringBuilder
            Using textWriter As New System.IO.StringWriter(sbRet)
                Using codeWriter As New IndentedTextWriter(textWriter)
                    provider.GenerateCodeFromCompileUnit(codeUnitToShow, codeWriter, vbNetOptions)
                End Using
            End Using
            Return sbRet.ToString()
        End Using


    End Function

For example if I assemble a code graph thus:-

Imports System.CodeDom

'...

        Dim interfaceObj As CodeTypeDeclaration = CodeGeneration.InterfaceCodeGeneration.InterfaceDeclaration("Duncan's Interface")
        Dim interfaceHolder As New CodeCompileUnit
        Dim nsMain As New CodeNamespace("test")
        interfaceHolder.Namespaces.Add(nsMain)
        nsMain.Types.Add(interfaceObj)

Using the interface code generation function as:-

    Public Shared Function InterfaceDeclaration(ByVal entityName As String) As CodeTypeDeclaration

        Dim interfaceDeclarationRet As CodeTypeDeclaration = New CodeTypeDeclaration(ModelCodeGenerator.MakeInterfaceName(entityName))
        interfaceDeclarationRet.IsPartial = True
        interfaceDeclarationRet.IsInterface = True

        Return interfaceDeclarationRet

    End Function

The resulting code in the string will look like:

'------------------------------------------------------------------------------
' <auto-generated>
'     This code was generated by a tool.
'     Runtime Version:4.0.30319.42000
'
'     Changes to this file may cause incorrect behavior and will be lost if
'     the code is regenerated.
' </auto-generated>
'------------------------------------------------------------------------------

Option Strict Off
Option Explicit On


Namespace test
    
    Partial Public Interface IDuncan_s_Interface
    End Interface
End Namespace