Improve debug views of dictionaries

[JamesNK]

Fixes #51827

Update custom dictionaries in ASP.NET Core to display the key in the name column. There are a lot of dictionaries and I haven't tested all of them, but reusing debugger proxies on most dictionary types means they should just work.

Background: .NET debugging has supported customizing the name for years, but for some reason dictionaries have always displayed a meaningless index in the name column instead of the item key. See dotnet/runtime#88736

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Items before:

Items after:

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Cookies before:

Cookies after:

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Request headers before:

Request headers after:

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Route values before:

Route values after:

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Features before:

Features after:

[Meligy]

I have mixed feelings about this. Not sure I want to lose sight of index. Although I welcome an easier to read key.

Is 3 columns easily possible? Or some format that preserves the index?

[JamesNK]

Three columns isn't possible. What do you want the existing number in the name column for? It is meaningless. The new value is actually the index.

For example:

var headers = new Dictionary<string, string> { ["content-type"] = "application/json" };
var v1 = headers["content-type"]; // works
var v2 = headers[0]; // trying to use the number causes a compile error that a string is expected

And displaying the number becomes confusing in the cases when the dictionary key is an integer:

var products = new Dictionary<int, string> { [1] = "Apple", [0] = "Orange" };

[halter73]

One more thing. In the screenshot, one of the headers shows up as ["Accept-Encoding"] "gzip, deflate, br". It should probably be ["Accept-Encoding"] "gzip", "deflate", "br". This would make it easier to tell if the request was

Accept-Encoding: gzip
Accept-Encoding: deflate
Accept-Encoding: br

vs

Accept-Encoding: gzip, deflate, br

Of course, the server should handle it the same way, but I could see it mattering for query strings or something. Since quotes inside the StringValue are already getting escaped with \", I think it would only make it more clear to quote each value independently when there are multiple.

[JamesNK]

I took a look at the value and at least in this case the StringValues is one string:

I presume Chrome is sending the header as one comma delimited value instead of separate values.