After deserialization, while fetching data from JSON if array don't have any value the error occur.

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"patients": [
    {
      "addresses": [
        {
          "city": "",
          "country": "United States of America",
          "county": "",
          "district": null,
          "email": [],
          "houseNumber": null,
          "phoneNumbers": [],
          "postalCode": "",
          "state": "",
          "street": [],
          "type": "Permanent"
        }]}]

this one is json format I am using and the code is like below to get the data,I am getting exceptions at the last line so if there is no data in JSON and it's in array format how do not get an exception, is there any typecasting of an array or something.. plz improve my code there

I am getting error here

if (!string.IsNullOrWhiteSpace(dJson6[0].ToString())  )
                   {
                       kv.Add("Address1", dJson6[0].ToString());
                   }}

What I have tried:

kv = new Dictionary<string, string>();
                  listKV = new List<Dictionary<string, string>>();



               FileInfo FI = new FileInfo(@"D:\Suraj\navicent\patientresponse500102785.json");
               FileStream FS = FI.Open(FileMode.OpenOrCreate, FileAccess.Read, FileShare.Read);
               StreamReader sJson = new StreamReader(FS);

               string fileContent = sJson.ReadToEnd();
               //dynamic Valuejson = JsonConvert.DeserializeObject<dynamic>(fileContent);
               dynamic Valuejson = new JavaScriptSerializer().Deserialize<dynamic>(fileContent);
               dynamic dJson = Valuejson["patients"][0];
                   Log.Write("Value in djson  " + dJson.ToString());
                   dynamic dJson2 = dJson["nameComponents"];
                   Log.Write("Value in dJson2 is  " + dJson2.ToString());
                   if (!string.IsNullOrWhiteSpace(dJson2["lastName"].ToString()))
                   {
                       kv.Add("Last Name", dJson2["lastName"].ToString());
                       Log.Write("Value in kv  " + kv.ToString());
                   }
                     dynamic dJson6 = dJson4["street"];

                   if (!string.IsNullOrWhiteSpace(dJson6[0].ToString())  )
                   {
                       kv.Add("Address1", dJson6[0].ToString());
                   }}

Posted 29-Jun-22 2:50am

Suraj Ingle

Updated 29-Jun-22 3:37am

v2

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Chris Copeland · Accepted Answer · 2022-06-29T03:37:00

First, you should consider naming your variables something easier to understand. dJson2 is not a good way to name something, especially when you add more and more of these variables. Instead, give it a meaningful name like nameComponents so you know what it is in the future.

Second, for the issue you're seeing, it's primarily because you're not doing safety checks to ensure that there is available data. If you look at your JSON:

"state": "",
"street": [], <<--------
"type": "Permanent"

You can clearly see that the street is an empty array, therefore the length (once deserialized) will be 0. Now, let's look at your code:

  dynamic dJson6 = dJson4["street"];

if (!string.IsNullOrWhiteSpace(dJson6[0].ToString())  ) <<--------
{
    kv.Add("Address1", dJson6[0].ToString());
}}

What you've done here is get the value of the "street" property (which is that empty array with a length of 0) and then tried to access the first element in the array. But, there is no element at index 0 because the array is empty! So, this will throw an exception. You need to add a check to ensure that at least one value exists in the array before attempting to access it.

Finally, I don't know why you're using JavaScriptSerializer for handling JSON content. The best practise is to instead create classes which match the structure of your JSON, and then deserialize the JSON into these class objects:

How to serialize and deserialize JSON using C# - .NET | Microsoft Docs[^]
Deserialize an Object[^]