Get Currency Exchange Rate using C# and VB.Net in ASP.Net

Hi nauna,

Check this example. Now please take its reference and correct your code.

HTML

<asp:TextBox runat="server" ID="txtSymbol" />
<asp:Button Text="Get Value" runat="server" OnClick="OnConvert" /><hr />
Rate : <asp:Label ID="lblValue" runat="server" />

Code

C#

protected void OnConvert(object sender, EventArgs e)
{
    string json = new System.Net.WebClient()
                .DownloadString("https://openexchangerates.org/api/latest.json?app_id=APP_Key&symbols=" + txtSymbol.Text.Trim());
    System.Web.Script.Serialization.JavaScriptSerializer js = new System.Web.Script.Serialization.JavaScriptSerializer();
    CurrencyRate rates = js.Deserialize<CurrencyRate>(json);
    KeyValuePair<string, decimal> rate = rates.Rates.FirstOrDefault();
    decimal currentrate = decimal.Parse(rate.Value.ToString());
    lblValue.Text = currentrate.ToString();
}

public class CurrencyRate
{
    public string Disclaimer { get; set; }
    public string License { get; set; }
    public int TimeStamp { get; set; }
    public string Base { get; set; }
    public Dictionary<string, decimal> Rates { get; set; }
}

VB.Net

Protected Sub OnConvert(ByVal sender As Object, ByVal e As EventArgs)
    Dim json As String = New Net.WebClient() _
                        .DownloadString("https://openexchangerates.org/api/latest.json?app_id=APP_Key&symbols=" & txtSymbol.Text.Trim())
    Dim js As Script.Serialization.JavaScriptSerializer = New Script.Serialization.JavaScriptSerializer()
    Dim rates As CurrencyRate = js.Deserialize(Of CurrencyRate)(json)
    Dim rate As KeyValuePair(Of String, Decimal) = rates.Rates.FirstOrDefault()
    Dim currentrate As Decimal = Decimal.Parse(rate.Value.ToString())
    lblValue.Text = currentrate.ToString()
End Sub

Public Class CurrencyRate
    Public Property Disclaimer As String
    Public Property License As String
    Public Property TimeStamp As Integer
    Public Property Base As String
    Public Property Rates As Dictionary(Of String, Decimal)
End Class

Screenshot