Bug Report Checklist

• Have you provided a full/minimal spec to reproduce the issue?
• Have you validated the input using an OpenAPI validator (example)?
• Have you tested with the latest master to confirm the issue still exists?
• Have you searched for related issues/PRs?
• What's the actual output vs expected output?
• [Optional] Sponsorship to speed up the bug fix or feature request (example)

Description

Running the generator against a stablediffusion webui on Windows creates invalid escape sequences because its openapi.json includes defaults that are properly escaped, but OpenAPI incorrectly unescapes them.

 java -jar modules/openapi-generator-cli/target/openapi-generator-cli.jar generate  -i openapi.json  -g csharp-netcore --library unityWebRequest --skip-validate-spec

The generator needs to not unescape backslashes and use the default strings literally.

openapi.zip

openapi-generator version

a601002 (HEAD at time of writing)

OpenAPI declaration file content or url

attached

critical section:

          "data_dir": {
            "title": "Data Dir",
            "type": "string",
            "description": "base path where all user data is stored",
            "default": "C:\\Users\\bberman\\Documents\\stable-diffusion-webui"
          },

Generation Details

 java -jar modules/openapi-generator-cli/target/openapi-generator-cli.jar generate  -i http://127.0.0.1:7860/openapi.json  -g csharp-netcore --library unityWebRequest --skip-validate-spec

Steps to reproduce

1. Download the attached zip.
2. Unpack it.
3. Run the generation command.

Related issues/PRs

(none)

Suggest a fix

{{{defaultValue}}} for strings in csharp-netcore should be verbatim strings (i.e. @"...")

diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractCSharpCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractCSharpCodegen.java
index 651a015111b..571061a6587 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractCSharpCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractCSharpCodegen.java
@@ -1121,7 +1121,7 @@ public abstract class AbstractCSharpCodegen extends DefaultCodegen implements Co
             if (p.getDefault() != null) {
                 String _default = String.valueOf(p.getDefault());
                 if (p.getEnum() == null) {
-                    return "\"" + _default + "\"";
+                    return "@\"" + _default + "\"";
                 } else {
                     // convert to enum var name later in postProcessModels
                     return _default;