public static class FormExtensions
 {
    private class DirectPostForm : IDisposable
    {
        private readonly HtmlHelper _helper;

        public DirectPostForm(HtmlHelper helper, string apiLogin, string transactionKey, decimal amount,
            string returnUrl, bool isTest)
        {
            _helper = helper;
            _helper.ViewContext.Writer.Write(DPMFormGenerator.OpenForm(apiLogin, transactionKey, amount, returnUrl,
                isTest));
        }

        public void Dispose()
        {
            _helper.ViewContext.Writer.Write(DPMFormGenerator.EndForm());
        }
    }

    public static IDisposable BeginDirectPostForm(this HtmlHelper helper, string apiLogin, string transactionKey,
        decimal amount,
        string returnUrl, bool isTest)
    {
        return new DirectPostForm(helper, apiLogin, transactionKey, amount, returnUrl, isTest);
    }
}