I am new to using JSON and I am struggling to return specifically a list, within a list. I get the following JSON:
{
"parameters": {
"tbdb": "trudon",
"min_prefix_length": "2",
"service": "prefix",
"template": "service.json",
"term_prefix": "plu"},
"termHints": [
{
"name": "Plumbers & Sanitary Engineers",
"id":"209654",
"values": {
"value":"Plumbers & Sanitary Engineers",
"pre_em":"",
"em":"Plu",
"post_em":"mbers & Sanitary Engineers",
"nature":"PT",
"id":"209654"
}
},
],
"facets": [
{
"id":"209654",
"name":"Plumbers & Sanitary Engineers"
}
],
"total":1
}
I have desrialized this using the the JSON DataContractJsonSerializer and it looks like the following:
edited: made the changes that were suggested by carlosfigueira here
[DataContract]
public class AutoCompleteResponse
{
[DataMember(Name = "parameters")]
public Parameter Parameters { get; set; }
[DataMember(Name = "termHints")]
public List<termHints> hints { get; set; }
[DataMember(Name = "total")]
public string Total { get; set; }
}
[DataContract]
public class Parameter
{
[DataMember(Name = "tbdb")]
public string tbdb { get; set; }
[DataMember(Name = "min_prefix_length")]
public string min_prefix_length { get; set; }
[DataMember(Name = "service")]
public string service { get; set; }
[DataMember(Name = "template")]
public string template { get; set; }
[DataMember(Name = "term_prefix")]
public string term_prefrix { get; set; }
}
[DataContract]
public class termHints
{
[DataMember(Name = "name")]
public string Name { get; set; }
[DataMember(Name = "id")]
public string id { get; set; }
[DataMember(Name = "values")]
public values Values { get; set; }
[DataMember(Name = "facets")]
public facets Facets { get; set; }
}
[DataContract]
public class values
{
[DataMember(Name = "value")]
public string value_name { get; set; }
[DataMember(Name = "pre_em")]
public string pre_em { get; set; }
[DataMember(Name = "em")]
public string em { get; set; }
[DataMember(Name = "post_em")]
public string post_em { get; set; }
[DataMember(Name = "nature")]
public string nature { get; set; }
[DataMember(Name = "id")]
public string value_id { get; set; }
}
[DataContract]
public class facets
{
[DataMember(Name = "id")]
public string facet_id { get; set; }
[DataMember (Name = "name")]
public string facet_name {get; set; }
}
The serialization I do looks like the following:
WebClient w = new WebClient();
w.DownloadStringCompleted += (a, b) =>
{
// Check for errors
if (b == null) { return; }
if (b.Error != null) { return; }
if (string.IsNullOrEmpty(b.Result)) { return; }
// Desearealize from JSON to .NET objects
Byte[] bytes = Encoding.Unicode.GetBytes(b.Result);
MemoryStream memoryStream = new MemoryStream(bytes);
DataContractJsonSerializer dataContractJsonSerializer = new DataContractJsonSerializer(typeof(AutoCompleteResponse));
AutoCompleteResponse autocompleteSearchResponse = dataContractJsonSerializer.ReadObject(memoryStream) as AutoCompleteResponse;
memoryStream.Close();
// Raise Event
this.OnSearchCompleted(
new WhatEventArgs()
{
response = autocompleteSearchResponse
}
);
};
w.DownloadStringAsync(builder.Uri);
The return I create looks like the following:
public class WhatEventArgs : EventArgs
{
public AutoCompleteResponse response { get; set; }
}
*edit: adding the code that is used to get the data here incase this is helpful… This is how I am getting the data from the values, perhaps I am doing something wrong but I am not getting any data (it’s null) and I have no idea what I have done wrong *
protected void cmdSearch_Click(object sender, EventArgs e)
{
AutocompleteWhat search = new AutocompleteWhat()
{
Num = 2
};
search.SearchCompleted += (a, b) =>
{
List<values> _value = new List<values>();
foreach (termHints item in b.response.hints)
{
_value.Add(item.Values);
}
if (_value.Count > 0)
{
dgvResults.DataSource = _value;
}
else
{
dgvResults.DataSource = null;
}
dgvResults.DataBind();
};
search.Search("plu");
}
I now need to get the actual values from hints, however the data returned from values is empty. I have no idea why, please see if you can see what I can not see.
edit Fixed the Json, was missing the closing ] for “facets”
For the
DataContractJsonSerializerto work you need to have the a type system with the schema which matches the JSON. The “values” field isn’t a list (or an array) – it’s another JSON object, so you don’t need to declare it as aList<Value>– it’s just a Value object there.Also, the DataMember Name properties on the termHints class are set to ‘Values’ and ‘Facets’ for their respective members, but in the json the names are in lower case, so you’ll need to change that as well (DataMember(Name = “values”) and DataMember(Name = “facets”).
Update with code
Another problem I see in the code / JSON is that in the JSON document,
facetsis a sibling oftermHints, but in the data contracts you have, the facets are a child of the hints. So one of those needs to be changed. Below is a code with both versions, just pick one 🙂