C# how to use parameters reading different parts of a Json output?

Question

Hello. I will need assistance with figuring out how to use parameters to read a different part of a Json file output. My project involves getting a response from coinmarketcap api and getting coin price value. See below sample. This part works fine.

while(sqlReader.Read()) 
{
    dynamic jObj = JsonConvert.DeserializeObject<dynamic>(response);
    decimal jUSDPrice = jObj.data.BTC[0].quote.USD.price;                 
}

Now, my challenge is to use a parameter CoinCode instead of hardcoded BTC so every time sql reader reads new record it will pull our new coin price eg ETH,XRP etc.

How do I use a variable so it looks similar to below?

decimal jUSDPrice = jObj.data.CoinName[0].quote.USD.price;

Your help will be much appreciated.
CC

Daniel Wright · Answer

Certainly! You are on the right track by wanting to use a parameter to dynamically read different parts of a Json output based on the CoinCode provided. To achieve this in C#, you can use the following approach: while (sqlReader.Read()) { dynamic jObj = JsonConvert.DeserializeObject (response); // Assuming CoinCode is a variable holding the coin's code like "ETH", "XRP", etc. string coinCode = sqlReader["CoinCode"].ToString(); // Assuming "CoinCode" is the column name from SQL Reader decimal jUSDPrice = jObj.data[coinCode][0].quote.USD.price; } In this code snippet: 1. We first retrieve the coin code from the SQL Reader assuming it is stored in a column named "CoinCode." 2. Then, we use this coin code dynamically to access the corresponding part of the Json output using `jObj.data[coinCode]`. This way, every time the SQL Reader reads a new record, the `CoinCode` parameter will determine which coin's price value to extract from the Json output. I hope this helps clarify how you can use parameters to read different parts of a Json output based on the CoinCode provided. Let me know if you need further assistance or more explanation!

Tuhin Paul · Answer

By using indexer syntax ( jObj.data[coinCode] ), you can dynamically access JSON properties based on a variable. This approach integrates seamlessly with your SQL reader and allows you to process multiple coin codes efficiently.

Tuhin Paul · Answer

Assume the JSON response from the CoinMarketCap API looks like this: { "data": { "BTC": [ { "quote": { "USD": { "price": 27000.50 } } } ], "ETH": [ { "quote": { "USD": { "price": 1800.75 } } } ] } } For coinCode = "BTC" , the code accesses jObj.data["BTC"][0].quote.USD.price . For coinCode = "ETH" , the code accesses jObj.data["ETH"][0].quote.USD.price .

Tuhin Paul · Answer

while (sqlReader.Read()) { // Assuming CoinCode is read from the SQL reader string coinCode = sqlReader["CoinCode"].ToString(); // Example: "BTC", "ETH", "XRP" // Deserialize the JSON response into a dynamic object dynamic jObj = JsonConvert.DeserializeObject (response); // Use the variable `coinCode` to dynamically access the JSON property decimal jUSDPrice = jObj.data[coinCode][0].quote.USD.price; // Output or process the price as needed Console.WriteLine($"The price of {coinCode} is {jUSDPrice}"); } Dynamic Access with Indexer Syntax : The data object in your JSON is essentially a dictionary-like structure where keys are coin codes (e.g., "BTC" , "ETH" ). Using jObj.data[coinCode] allows you to dynamically access the value associated with the key stored in the coinCode variable. SQL Reader Integration : The sqlReader["CoinCode"] retrieves the coin code (e.g., "BTC" , "ETH" ) from the current record in the SQL result set. This value is then used to fetch the corresponding price from the JSON response. Deserialization : The JsonConvert.DeserializeObject (response) converts the JSON string into a dynamic object, enabling flexible access to its properties.

Tuhin Paul · Answer

To dynamically access a part of a JSON object using a variable (e.g., CoinCode ), you can use indexer syntax in C#. This allows you to replace the hardcoded key (like "BTC" ) with a variable. Here's how you can modify your code to achieve this: Use Indexer Syntax : Instead of hardcoding the key ( BTC ), you can use a variable (e.g., CoinCode ) to dynamically access the corresponding part of the JSON object. In C#, dynamic objects allow you to use indexer syntax ( [] ) to access properties dynamically. Modify Your Code : Replace the hardcoded key with a variable that changes for each record in your SQL reader.