C#

MessageBoxManager.Yes = "Yes/Oo";
MessageBoxManager.No = "No/Hindi";
MessageBoxManager.Unregister();

{"store": [
{
    "name": "Sunshine Department Store",
    "address": "Wangfujing Street",
    "goods": {
        "book": [
            {
                "category": "Reference",
                "title": "Sayings of the Century",
                "author": "Nigel Rees",
                "price": 8.88
            },
            {
                "category": "Fiction",
                "title": "Sword of Honour",
                "author": "Evelyn Waugh",
                "price": 12.66
            }
        ],
        "bicycle": {
            "type": "GIANT OCR2600",
            "color": "White",
            "price": 276
        }
    }
}
]
}

private string ParseBookNode(JObject bookJSONFile)
        {
            JArray bookJson = null;
            string bookFarmNode = null;
            if (bookJSONFile != null && bookJSONFile["store"] != null)
            {
                bookJson = (JArray)bookJSONFile["store"];
                bookFarmNode = bookJson[0].ToString();

                if (bookJSONFile["book"] != null)
                {
                    bookJson = (JArray)bookJSONFile["book"];
                    bookFarmNode = bookJson[0].ToString();
                }
            }
            else
            {
                throw new Exception("Book node not found.");
            }
            return bookFarmNode;
        }

if (bookJSONFile["book"] != null)
                {
                    bookJson = (JArray)bookJSONFile["book"];
                    bookFarmNode = bookJson[0].ToString();
                }

private void totalsize_TextChanged(object sender, EventArgs e)
{
    if (System.Text.RegularExpressions.Regex.IsMatch(totalsize.Text, "[^0-9]"))
    {
        MessageBox.Show("Please enter only full numbers i.e. 70  NOT  65.5");
        totalsize.Text = totalsize.Text.Remove(totalsize.Text.Length - 1);
        totalsize.Focus();
    }
}

private void nicstrength_TextChanged(object sender, EventArgs e)
{
        if (System.Text.RegularExpressions.Regex.IsMatch(nicstrength.Text, "insert jibberish here"))
        {
            MessageBox.Show("Please enter only numbers.");
            nicstrength.Text = nicstrength.Text.Remove(nicstrength.Text.Length - 1);
            nicstrength.Focus();
        }

    }

private void finalnicstrength_TextChanged(object sender, EventArgs e)
{
    if (System.Text.RegularExpressions.Regex.IsMatch(finalnicstrength.Text, @"^[1-9]\d*(\.\d+)?$"))
    {
        MessageBox.Show("Please enter only numbers.");
        finalnicstrength.Text = finalnicstrength.Text.Remove(finalnicstrength.Text.Length - 1);
        finalnicstrength.Focus();
    }
}