The 'name' does not exist in the current context C#

Question

I was using the sample code for my project to export Html-pdf using EvoPdf converter. This is the If Else statement.

if (convertUrlRadioButton.Checked)
            {
                string url = urlTextBox.Text;
                outPdfBuffer = htmlToPdfConverter.ConvertUrl(url);
            }
            else
            {
                string htmlString = htmlStringTextBox.Text;
                string baseUrl = baseUrlTextBox.Text;
                outPdfBuffer = htmlToPdfConverter.ConvertHtml(htmlString, baseUrl);
            }

The name convertUrlRadioButton does not exists in the current context

I get this error, The name 'convertUrlRadioButton' does not exist in the current context. What am I doing wrong?

I tried to generate a field object with the name convertUrlRadioButton but

'type' does not contain a definition for 'name' and no accessible extension method 'name' accepting a first argument of type 'type' could be found (are you missing a using directive or an assembly reference?). This error occurs.