使用路由在 QueryParameters 中传递字典

Question

I want to pass a dictionary through my controller using .Net Web Api.

Unfortunately it isn't working as described at Microsoft Docs .

My code looks the following:

[HttpGet]
[Route("{key}")]
public ResponseType SearchObjects([FromUri] string key, 
    [FromUri]Dictionary<string, string> options) {}

The parameter 'index' works, but the parameter 'options' is always empty (length=0)...

Requests I've tried so far:

http://localhost/key?index=1&filter[foo]=bar

http://localhost/key?index=1&filter[ 'foo']=bar

http://localhost/key?index=1&filter.foo=bar

Anyone sees what I'm missing? Are there any steps to debug/simulate the serialisation?

Answer 1

You could use JSON! Just add the Newtonsoft.Json Package

Some thing like:

    [HttpGet("{json}")]
    public async Task<IActionResult> GetAsync([FromRoute] string json)
    {
        var dictionary = JsonConvert.DeserializeObject<IDictionary<string, string>>(json);
        return await Task.FromResult(Ok());
    }

EDIT:

Exemple of JSON:

{ "Key1": "Value1", "Key2": "Value2", "Key3": "Value3" }

Answer 2

My solution now is a bit hacky but it seems that there isn't any better way at the moment...

There is a Method parameter just as before. To pass around the problem, that the Web Api not fills the dictionary automatically, I've implemented my own method... (If the Web Api does it in a later release, it will be simle to remove the method and everything should work then...

[HttpGet]
[Route("{key}")]
public ResponseType SearchObjects([FromUri] string key, [FromUri] Dictionary<string, string> options)
{
    AddMatchingQueryParamsToDictionary(Request, nameof(options), options);
    //options are now ready to use
}


/// <summary>
/// Fills the dictionary with additional values found in query parameters
/// In the query parameters given by the request, dictionary items will be in the format "dictName.dictKey".
/// </summary>
private static void AddMatchingQueryParamsToDictionary(HttpRequestMessage request, string dictionaryModelName, IDictionary<string, string> dictionaryToFill)
{
    var queryParams = request.GetQueryNameValuePairs();
    queryParams
        .Where(pair => pair.Key.StartsWith(dictionaryModelName))
        .Select(pair =>
        {
            var key = pair.Key;
            var index = key.IndexOf(dictionaryModelName, StringComparison.InvariantCultureIgnoreCase);
            var newKey = index < 0 ? key : key.Remove(index, dictionaryModelName.Length + 1 /*the dot*/);
            return (key: newKey, value: pair.Value);
        }).ToList()
        .ForEach(pair => dictionaryToFill[pair.key] = pair.value);
}

What do you think about this solution?