Wpf C# login system with hashing and databas

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C#

WPF

MySQL

hash

I want to make an account system with login and register. I already have the login system, this is also connected to the database. However, the passwords are not hashed. I can't find any help on how to do the hashing in connection with the database and the same thing with a register system.

What I have tried:

private void btn_login_Click(object sender, RoutedEventArgs e)
        {
            SqlConnection sqlCon = new SqlConnection("Server=xxxxx;Database=x;User Id=xxx;Password=xx;");
            try
            {
                if (sqlCon.State == System.Data.ConnectionState.Closed)
                    sqlCon.Open();
                String query = "SELECT COUNT(1) FROM tblUser WHERE Username=@Username AND Password=@Password";
                SqlCommand sqlCmd = new SqlCommand(query, sqlCon);
                sqlCmd.CommandType = System.Data.CommandType.Text;
                sqlCmd.Parameters.AddWithValue("@Username", txtUsername.Text);
                sqlCmd.Parameters.AddWithValue("@Password", txtPassword.Text);
                int count = Convert.ToInt32(sqlCmd.ExecuteScalar());
                if (count == 1)
                {
                    MessageBox.Show("Success!");
                }
                else
                {
                    MessageBox.Show("Wrong!");
                }
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
            }
            finally
            {
                sqlCon.Close();
            }
        }

private static string GetSHA384(string userID, string password)
{
    // SHA classes are disposable, use using to ensure any managed resources are properly disposed of by the runtime
    using SHA384 sha = new SHA384CryptoServiceProvider();

    // convert the username and password into bytes
    byte[] preHash = Encoding.ASCII.GetBytes(userID + password);

    // hash the bytes
    byte[] hash = sha.ComputeHash(preHash);

    // convert the raw bytes into a string that we can save to a database
    return Convert.ToBase64String(hash);
}