Add VB side.

src/Features/CSharp/Portable/ConvertToInterpolatedString/CSharpConvertConcatenationToInterpolatedStringRefactoringProvider.cs

@@ -10,7 +10,7 @@
 
 namespace Microsoft.CodeAnalysis.CSharp.ConvertToInterpolatedString
 {
-    [ExportCodeRefactoringProvider(LanguageNames.CSharp, Name = PredefinedCodeRefactoringProviderNames.ConvertToInterpolatedString + "2"), Shared]
+    [ExportCodeRefactoringProvider(LanguageNames.CSharp, Name = PredefinedCodeRefactoringProviderNames.ConvertToInterpolatedString), Shared]
     internal class CSharpConvertConcatenationToInterpolatedStringRefactoringProvider :
         AbstractConvertConcatenationToInterpolatedStringRefactoringProvider
     {

src/Features/Core/Portable/ConvertToInterpolatedString/AbstractConvertConcatenationToInterpolatedStringRefactoringProvider.cs

@@ -125,8 +125,9 @@ private bool SameLiteralKind(SyntaxNode literal1, SyntaxToken firstStringToken)
 
             var method = semanticModel.GetSymbolInfo(expression, cancellationToken).Symbol as IMethodSymbol;
             return method?.MethodKind == MethodKind.BuiltinOperator &&
-                   method.MetadataName == WellKnownMemberNames.AdditionOperatorName &&
-                   method.ContainingType.SpecialType == SpecialType.System_String;
+                   method.ContainingType.SpecialType == SpecialType.System_String &&
+                   (method.MetadataName == WellKnownMemberNames.AdditionOperatorName ||
+                    method.MetadataName == WellKnownMemberNames.ConcatenateOperatorName);
         }
 
         private class MyCodeAction : CodeAction.DocumentChangeAction

src/Features/VisualBasic/Portable/BasicFeatures.vbproj

@@ -123,6 +123,7 @@
     <Compile Include="CodeFixes\Spellcheck\VisualBasicSpellCheckCodeFixProvider.vb" />
     <Compile Include="CodeFixes\Suppression\VisualBasicSuppressionCodeFixProvider.vb" />
     <Compile Include="CodeLens\VisualBasicDisplayInfoService.vb" />
+    <Compile Include="ConvertToInterpolatedString\VisualBasicConvertConcatenationToInterpolatedStringRefactoringProvider.vb" />
     <Compile Include="ConvertToInterpolatedString\VisualBasicConvertPlaceholderToInterpolatedStringRefactoringProvider.vb" />
     <Compile Include="CodeRefactorings\EncapsulateField\EncapsulateFieldRefactoringProvider.vb" />
     <Compile Include="CodeRefactorings\ExtractInterface\ExtractInterfaceCodeRefactoringProvider.vb" />

src/Features/VisualBasic/Portable/ConvertToInterpolatedString/VisualBasicConvertConcatenationToInterpolatedStringRefactoringProvider.vb

+' Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
+
+Imports System.Composition
+Imports Microsoft.CodeAnalysis.CodeRefactorings
+Imports Microsoft.CodeAnalysis.ConvertToInterpolatedString
+Imports Microsoft.CodeAnalysis.VisualBasic.Syntax
+
+Namespace Microsoft.CodeAnalysis.VisualBasic.ConvertToInterpolatedString
+    <ExportCodeRefactoringProvider(LanguageNames.VisualBasic, Name:=PredefinedCodeRefactoringProviderNames.ExtractMethod), [Shared]>
+    Friend Class VisualBasicConvertConcatenationToInterpolatedStringRefactoringProvider
+        Inherits AbstractConvertConcatenationToInterpolatedStringRefactoringProvider
+
+        Protected Overrides Function CreateInterpolatedString(firstStringToken As SyntaxToken,
+                                                              pieces As List(Of SyntaxNode)) As SyntaxNode
+
+            Dim startToken = SyntaxFactory.Token(SyntaxKind.DollarSignDoubleQuoteToken).
+                                           WithLeadingTrivia(pieces.First().GetLeadingTrivia())
+
+            Dim endToken = SyntaxFactory.Token(SyntaxKind.DoubleQuoteToken).
+                                         WithTrailingTrivia(pieces.Last().GetTrailingTrivia())
+
+            Dim contents As New List(Of InterpolatedStringContentSyntax)
+            For Each piece In pieces
+                If piece.Kind() = SyntaxKind.StringLiteralExpression Then
+                    Dim text = piece.GetFirstToken().Text
+                    Dim textWithoutQuotes = text.Substring("'".Length, text.Length - "''".Length)
+
+                    contents.Add(SyntaxFactory.InterpolatedStringText(
+                                 SyntaxFactory.InterpolatedStringTextToken(textWithoutQuotes, "")))
+                Else
+                    contents.Add(SyntaxFactory.Interpolation(
+                                 DirectCast(piece, ExpressionSyntax).WithoutTrivia()))
+                End If
+            Next
+
+            Dim expression = SyntaxFactory.InterpolatedStringExpression(
+                startToken, SyntaxFactory.List(contents), endToken)
+
+            Return expression
+        End Function
+    End Class
+End Namespace