Word to PDF C#

Code :

 using System;  
 using System.Collections.Generic;  
 using System.ComponentModel;  
 using System.Data;  
 using System.Drawing;  
 using System.Linq;  
 using System.Text;  
 using System.Threading.Tasks;  
 using System.Windows.Forms;  
 using Microsoft.Office.Interop.Word;  
 using Microsoft.Office.Interop;  
 namespace WordToPdf  
 {  
   public partial class WordPDF : Form  
   {  
     public WordPDF()  
     {  
       InitializeComponent();  
     }  
     private void button1_Click(object sender, EventArgs e)  
     {  
       //set filter  
       openFileDialog1.Filter = "Document Word|*.doc;*.docx";  
       openFileDialog1.FilterIndex = 1;  
       openFileDialog1.Multiselect = false;  
       openFileDialog1.ShowDialog();  
       textBox1.Text = openFileDialog1.FileName;  
     }  
     private void button2_Click(object sender, EventArgs e)  
     {  
       saveFileDialog1.Filter = "PDF Format|*.pdf";  
       saveFileDialog1.ShowDialog();  
       textBox2.Text = saveFileDialog1.FileName;  
     }  
     private void button3_Click(object sender, EventArgs e)  
     {  
       this.timer1.Start();  
       Microsoft.Office.Interop.Word.Application appWord = new Microsoft.Office.Interop.Word.Application();  
       wordDocument = appWord.Documents.Open(textBox1.Text);  
       wordDocument.ExportAsFixedFormat(textBox2.Text, WdExportFormat.wdExportFormatPDF);  
     }  
     public Microsoft.Office.Interop.Word.Document wordDocument  
     {  
       get;  
       set;  
     }  
     private void progressBar1_Click(object sender, EventArgs e)  
     {  
     }  
     private void timer1_Tick(object sender, EventArgs e)  
     {  
       this.progressBar1.Increment(3);  
     }  
   }  
 }