I remember that the Fiddler ScriptEditor in JScript provided IntelliSense years ago.
Installing Fiddler now to a new machine, having C# selected as script language, IntelliSense seems to have gone.
It's utterly hard to program rules without being able to search and find appropriate properties of the oSession object.
How can I enable IntelliSense for the C# ScriptEditor?
7 Answers, 1 is accepted
Hi A,
IntelliSense should be enabled by default for the included using statements at the top of the CustomRules.cs file. For example, if you open the CustomRules.cs file from the Fiddler Installation folder in Visual Studio Code, it should be similar to the screenshot below. Note the CustomRules.cs file is located in the scripts folder: %localappdata%\Programs\Fiddler\Scripts
Can you confirm that this is happening?
In the meantime, please let me know if you need any additional information. Thank you for using the Fiddler Forums.
Regards,
Eric R | Senior Technical Support Engineer
Progress Telerik
Our thoughts here at Progress are with those affected by the outbreak.

Thanks for replying!
From your answer there are two things I don't quite understand ...
(a) The help pages tell to use {MyDocuments}\Fiddler2\Scripts\CustomRules.cs. Shouldn't I preferrably edit that file when I want to update rules on the fly?
(b) The help pages tell to use Fiddler ScriptEditor for editing the CustomRules.cs file. Isn't that option supported anymore? Is VS Code the preferred editor now?
When using VS Code on the CustomRules.cs file in the My Documents folder, I don't get no IntelliSense (of course).
Hi A,
My apologies, I misunderstood where the editing was happening. You are correct. For editing the CustomRules.{js|cs} file I do recommend using FiddlerScript Editor from within Fiddler. Additionally, the FiddlerScript Editor will only provide some code completion features as it is not a complete IntelliSense editor. See below screenshot for completion on the FiddlerApplication object from within the FiddlerScript Editor using the CustomRules file located in the Documents folder.
For additional object related information, the FiddlerScript Editor also includes an Object Browser as shown in the below screenshot.
As for IntelliSense, I believe this is a Visual Studio feature and could be related to how IntelliSense works since Visual Studio Code and the FiddlerScript editor behave the same way when editing the same file in the Documents folder. It may even have something to do with the location of the file as well. In order to get full IntelliSense I recommend using Visual Studio.
I hope this helps. Please let me know if you need any additional information regarding Fiddler. Thank you.
Regards,
Eric R | Senior Technical Support Engineer
Progress Telerik
Our thoughts here at Progress are with those affected by the outbreak.

Hello Eric,
I remember when I hit `oSession` years ago I got code completion by it's own IntelliSense mechanism. So, I believe, back those days, ScriptEditor loaded the `Fiddler` assembly in its workspace to accomplish that. It doesn't seem to do that anymore.
My current challenge ist: Visual Studio (Code) cannot provide IntelliSense when they do not know where to find the corresponding symbols.
I couldn't find the `Fiddler` assembly that's referenced in the `CustomRules.cs` file. It's neither in the GAC nor somewhere in the `C:\Users\...\AppData\Local\Programs\Fiddler\` folder.
Could you tell me where to find the `Fiddler` assembly that's referenced in the `CustomRules.cs` file?
Your help is very much appreciated.
Best regards,
Axel
Hi Axel,
At this time, we don't distribute the Fiddler assembly with the Desktop application. Although, we do ship the Fiddler assemblies when using the FiddlerCore NuGet packages. In this case, it may be possible to sign-up for a FiddlerCore trial and use the assembly directly during the trial. Note that use of the assemblies is governed by the FiddlerCore End User License Agreement.
I hope this helps. Please let me know if you need any additional information. Thank you.
Regards,
Eric R | Senior Technical Support Engineer
Progress Telerik
Our thoughts here at Progress are with those affected by the outbreak.

Thank your for your valuable replies, Eric.
May I suggest to publish an interface assembly with Fiddler, containing only the interfaces of all the Fiddler public types?
This way, IntelliSense could be used, both, with ScriptEditor and with any of the Visual Studio products.
That would require Telerik to derive their public classes, like Session, from an interface, like ISession. That interface would need to be stored in a separate assembly that would be published then along with Fiddler.
Would you mind forwarding my feature request to the team?
Cheers,
Axel
Hi Alex,
Thank you for your feedback. As a token of gratitude, I have created a public feedback request and increased the priority of the item by casting a vote on your behalf. The feedback item can be found at the Publish Public Interfaces of Fiddler.dll link. I encourage following the item to receive the latest updates.
In the meantime, please let me know if you need any additional information. Thank you.
Regards,
Eric R | Senior Technical Support Engineer
Progress Telerik
Our thoughts here at Progress are with those affected by the outbreak.