private void convertToPdfButton_Click(object sender, EventArgs e)
{
    // Create a HTML to PDF converter object with default settings
    HtmlToPdfConverter htmlToPdfConverter = new HtmlToPdfConverter();

    // Set license key received after purchase to use the converter in licensed mode
    // Leave it not set to use the converter in demo mode
    htmlToPdfConverter.LicenseKey = "fvDh8eDx4fHg4P/h8eLg/+Dj/+jo6Og=";

    string param1Name = param1NameTextBox.Text.Length > 0 ? param1NameTextBox.Text : "param1";
    string param1Value = param1ValueTextBox.Text.Length > 0 ? param1ValueTextBox.Text : "Value 1";

    string param2Name = param2NameTextBox.Text.Length > 0 ? param2NameTextBox.Text : "param2";
    string param2Value = param2ValueTextBox.Text.Length > 0 ? param2ValueTextBox.Text : "Value 2";

    string param3Name = param3NameTextBox.Text.Length > 0 ? param3NameTextBox.Text : "param3";
    string param3Value = param3ValueTextBox.Text.Length > 0 ? param3ValueTextBox.Text : "Value 3";

    string param4Name = param4NameTextBox.Text.Length > 0 ? param4NameTextBox.Text : "param4";
    string param4Value = param4ValueTextBox.Text.Length > 0 ? param4ValueTextBox.Text : "Value 4";

    string param5Name = param5NameTextBox.Text.Length > 0 ? param5NameTextBox.Text : "param5";
    string param5Value = param5ValueTextBox.Text.Length > 0 ? param5ValueTextBox.Text : "Value 5";

    string urlToConvert = urlTextBox.Text;

    if (postMethodRadioButton.Checked)
    {
        htmlToPdfConverter.HttpPostFields.Add(param1Name, param1Value);
        htmlToPdfConverter.HttpPostFields.Add(param2Name, param2Value);
        htmlToPdfConverter.HttpPostFields.Add(param3Name, param3Value);
        htmlToPdfConverter.HttpPostFields.Add(param4Name, param4Value);
        htmlToPdfConverter.HttpPostFields.Add(param5Name, param5Value);
    }
    else
    {
        Uri getMethodUri = new Uri(urlTextBox.Text);
                
        string query = getMethodUri.Query.Length > 0 ? "&" : "?" + String.Format("{0}={1}", param1Name, param1Value);
        query += String.Format("&{0}={1}", param2Name, param2Value);
        query += String.Format("&{0}={1}", param3Name, param3Value);
        query += String.Format("&{0}={1}", param4Name, param4Value);
        query += String.Format("&{0}={1}", param5Name, param5Value);

        urlToConvert = urlTextBox.Text + query;
    }
            
    Cursor = Cursors.WaitCursor;

    // Convert HTML to PDF using the settings above
    string outPdfFile = @"DemoAppFiles\Output\HTML_to_PDF\GET_and_POST.pdf";
    try
    {
        // Convert the HTML page to a PDF document in a memory buffer
        byte[] outPdfBuffer = htmlToPdfConverter.ConvertUrl(urlToConvert);

        // Write the memory buffer in a PDF file
        System.IO.File.WriteAllBytes(outPdfFile, outPdfBuffer);
    }
    catch (Exception ex)
    {
        // The HTML to PDF conversion failed
        MessageBox.Show(String.Format("HTML to PDF Error. {0}", ex.Message));
        return;
    }
    finally
    {
        Cursor = Cursors.Arrow;
    }

    // Open the created PDF document in default PDF viewer
    try
    {
        System.Diagnostics.Process.Start(outPdfFile);
    }
    catch (Exception ex)
    {
        MessageBox.Show(String.Format("Cannot open created PDF file '{0}'. {1}", outPdfFile, ex.Message));
    }
}