Switch to verbatim style escaping since all VB strings are verbatim

Author: GrahamTheCoder

CHANGELOG.md

@@ -8,6 +8,9 @@ All notable changes to the code converter will be documented here.
 ### C# -> VB
 * Improve event identifier conversion
 
+### VB -> C#
+* Improve conversion of interpolated strings (format, alignment, escaping)
+
 # 6.5.0 03/03/2019
 * Avoid fatal error converting a project in a solution containing a website project (#243)
 * Improve best-effort conversion in the presence of errors

ICSharpCode.CodeConverter/VB/NodesVisitor.cs

@@ -765,7 +765,13 @@ public override VisualBasicSyntaxNode VisitInterpolatedStringExpression(CSS.Inte
 
         public override VisualBasicSyntaxNode VisitInterpolatedStringText(CSS.InterpolatedStringTextSyntax node)
         {
-            return SyntaxFactory.InterpolatedStringText(SyntaxFactory.InterpolatedStringTextToken(node.TextToken.Text, node.TextToken.ValueText));
+            return SyntaxFactory.InterpolatedStringText(SyntaxFactory.InterpolatedStringTextToken(ConvertUserText(node.TextToken), node.TextToken.ValueText));
+        }
+
+        private static string ConvertUserText(SyntaxToken token)
+        {
+            if (CS.CSharpExtensions.IsVerbatimStringLiteral(token)) return token.Text;
+            return token.ValueText.Replace("\"", "\"\"");
         }
 
         public override VisualBasicSyntaxNode VisitInterpolation(CSS.InterpolationSyntax node)

Tests/VB/ExpressionTests.cs

@@ -39,6 +39,7 @@ public string StringInter(string t, DateTime dt)
             var a = $""pre{t} t"";
             var b = $""pre{t} \"" t"";
             var c = $@""pre{t} """"\ t"";
+            var d = $""pre{t + ""\""""} \"" t"";
             var e = $@""pre{t + ""\""""} """"\ t"";
             var f = $""pre{{escapedBraces}}{dt,4:hh}"";
             return a + b + c + d + e + f;
@@ -53,6 +54,7 @@ Public Function StringInter(ByVal t As String, ByVal dt As DateTime) As String
             Dim a = $""pre{t} t""
             Dim b = $""pre{t} """" t""
             Dim c = $""pre{t} """"\ t""
+            Dim d = $""pre{t & """"""""} """" t""
             Dim e = $""pre{t & """"""""} """"\ t""
             Dim f = $""pre{{escapedBraces}}{dt,4:hh}""
             Return a & b & c & d & e & f