[Yugabyte C# Driver for YCQL](https://github.com/yugabyte/cassandra-csharp-driver) is based on [DataStax C# Driver](https://github.com/datastax/csharp-driver) with additional [smart driver](../../smart-drivers-ycql/) features.
{{< note title="YugabyteDB Aeon" >}}
To use the driver's partition-aware load balancing feature in a YugabyteDB Aeon cluster, applications must be deployed in a VPC that has been peered with the cluster VPC so that they have access to all nodes in the cluster. For more information, refer to [Using YCQL drivers with YugabyteDB Aeon](../../smart-drivers-ycql/#using-ycql-drivers-with-yugabytedb-aeon).
{{< /note >}}
## Prerequisites
This tutorial assumes that you have:
- installed YugabyteDB, created a universe and are able to interact with it using the YCQL shell. If not, follow the steps in [Quick start](/stable/quick-start/macos/).
- installed Visual Studio.
## Write the HelloWorld C# app
In your Visual Studio create a new **Project** and choose **Console Application** as template. Follow the instructions to save the project.
### Install YugabyteDB C# Driver for YCQL
The [Yugabyte C# Driver for YCQL](https://github.com/yugabyte/cassandra-csharp-driver) is based on a fork of the Apache Cassandra C# Driver, but adds features unique to YCQL, including [JSONB support](../../../../api/ycql/type_jsonb/) and a different routing policy.
To install the [Yugabyte C# Driver for YCQL](https://www.nuget.org/packages/YugaByteCassandraCSharpDriver/) in your Visual Studio project, follow the instructions in the [README](https://github.com/yugabyte/cassandra-csharp-driver).
### Create the program
Copy the contents below to your `Program.cs` file:
```csharp
using System;
using System.Linq;
using Cassandra;
namespace Yugabyte_CSharp_Demo
{
class Program
{
static void Main(string[] args)
{
try
{
var cluster = Cluster.Builder()
.AddContactPoints("127.0.0.1")
.WithPort(9042)
.Build();
var session = cluster.Connect();
session.Execute("CREATE KEYSPACE IF NOT EXISTS ybdemo");
Console.WriteLine("Created keyspace ybdemo");
var createStmt = "CREATE TABLE IF NOT EXISTS ybdemo.employee(" +
"id int PRIMARY KEY, name varchar, age int, language varchar)";
session.Execute(createStmt);
Console.WriteLine("Created keyspace employee");
var insertStmt = "INSERT INTO ybdemo.employee(id, name, age, language) " +
"VALUES (1, 'John', 35, 'C#')";
session.Execute(insertStmt);
Console.WriteLine("Inserted data: {0}", insertStmt);
var preparedStmt = session.Prepare("SELECT name, age, language " +
"FROM ybdemo.employee WHERE id = ?");
var selectStmt = preparedStmt.Bind(1);
var result = session.Execute(selectStmt);
var rows = result.GetRows().ToList();
Console.WriteLine("Select query returned {0} rows", rows.Count());
Console.WriteLine("Name\tAge\tLanguage");
foreach (Row row in rows)
Console.WriteLine("{0}\t{1}\t{2}", row["name"], row["age"], row["language"]);
session.Dispose();
cluster.Dispose();
}
catch (Cassandra.NoHostAvailableException)
{
Console.WriteLine("Make sure YugabyteDB is running locally!.");
}
catch (Cassandra.InvalidQueryException ie)
{
Console.WriteLine("Invalid Query: " + ie.Message);
}
}
}
}
```
### Run the application
To run the C# app from the Visual Studio menu, select `Run > Start Without Debugging`.
You should see the following as the output.
```output
Created keyspace ybdemo
Created keyspace employee
Inserted data: INSERT INTO ybdemo.employee(id, name, age, language) VALUES (1, 'John', 35, 'C#')
Select query returned 1 rows
Name Age Language
John 35 C#
```