CODEWITHSUNDEEP
c#.net-coreconfigappsettings
Konrad Viltersten
Konrad Viltersten

Reputation: 39190

GetValue<T> always getting null/default regardless of type

I noticed that the following statement produces a discrepancy.

public static string GetValidation(this IConfiguration self, string key)
{
  IConfigurationSection section = self.GetSection(key);

  string value1 = section.Value;
  string value2 = section.GetValue<string>(key);

  return "";
}

The corresponding section in the config has correctly set value and is correctly located using the specified path.

...
"SomePath": "Some value",
"AlsoTried": 13,
"AndEven": true,
...

The first value is as expected, the content of the node. The second is null. When I tried typing to integers and booleans, I got zero and falsity, i.e. defaults (of course I changed the value in the config file to non-string, e.g. 13 and true respectively.

I've scrutinized the docs and googled the issue, coming up with nothing useful.

What am I missing here (because I'm sure like a rat's behind it's not a bug in .NET, hehe)?

Upvotes: 0

Views: 893

Answers (2)

Simply Ged
Simply Ged

Reputation: 8662

I'm going to assume you are passing test:SomeValue as your key and you configuration looks like:

"test": {
    "SomePath": "Some value",
    "AlsoTried": 13,
    "AndEven": true
}

Your call to self.GetSection(key); is returning the specific value you have asked for e.g.

var section = self.GetSection("test:SomePath");

This means section is now the "value" of that path e.g. Some value, which is why the section.Value property returns the correct data. But when you call section.GetValue<string>("test:SomePath") or just section.GetValue<string>("SomePath") then section does not contain a KeyValuePair for "SomePath", so you get null.

If you call GetValue<string>(key) on self it will return the correct value:

var section = self.GetValue<string>(key);

Upvotes: 2

Jawad
Jawad

Reputation: 11364

the values in your configuration should be all strings. Use GetValue to convert them to their proper formats. Configuration is supposed to be a dictionary of < string Key, string Value>.

"SomePath": "Some value",
"AlsoTried": "13",
"AndEven": "true",

with the following commands, you should get the proper values and their types

section.GetValue<int>("AlsoTried"); // out type will int and value 13.
section.GetValue<bool>("AndEven"); // out type will be bool and value true

hope it helps.
Found this URL that explains about Configuration and data retrieval as well. Good read.

Upvotes: 0

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