MainWindowViewModel.cs

using DevExpress.Mvvm;
using DevExpress.Mvvm.CodeGenerators;
using HTMLToQPDF.Example.Properties;
using HTMLToQPDF.Example.Utilities;
using System;
using System.IO;

namespace HTMLToQPDF.Example.ViewModels
{
    [GenerateViewModel]
    public partial class MainWindowViewModel : ViewModelBase
    {
        public string Html { get; set; }
        public string SavePath { get; set; }
        public bool CustomStyles { get; set; }

        public MainWindowViewModel()
        {
            Html = Resources.testHtml;
            var desktop = Environment.GetFolderPath(Environment.SpecialFolder.Desktop);
            SavePath = Path.Combine(desktop, "example.pdf");
        }

        [GenerateCommand]
        private void SelectSavePath()
        {
            SavePath = FileDialogHelper.GetSaveFilePath(SavePath);
        }

        [GenerateCommand]
        private void CreatePdf()
        {
            PdfCreator.Create(Html, SavePath, CustomStyles);
        }

        private bool CanCreatePdf() => !string.IsNullOrEmpty(Html);
    }
}