Import data excel to WPF

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C#

WPF

VS2012

I have a WPF, and i want the data which selected by a OpenFileDialog (from excel files), imported to GridControl, so wrote this.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Shapes;
using DevExpress.Xpf.Core;
using DevExpress.Xpf.Bars;
using DevExpress.Xpf.Grid;
using DevExpress.Xpf.Printing;
using System.ComponentModel;
using System.Collections.ObjectModel;
using DevExpress.Xpf.NavBar;
using System.Data.SqlClient;
using System.Data;
using System.Data.OleDb;
using Excel = Microsoft.Office.Interop.Excel;

...

    InitializeComponent();
        DataContext = new DataSource();
    }

    private void Button_Click_1(object sender, RoutedEventArgs e)
    {

    }

    private void Button_Click_2(object sender, RoutedEventArgs e)
    {


        // Create OpenFileDialog
        Microsoft.Win32.OpenFileDialog dlg = new Microsoft.Win32.OpenFileDialog();



        // Set filter for file extension and default file extension
        dlg.DefaultExt = ".txt";
        dlg.Filter = "EXCEL Files (*.xlsx)|*.xlsx";


        // Display OpenFileDialog by calling ShowDialog method
        Nullable<bool> result = dlg.ShowDialog();


        // Get the selected file name and display in a TextBox
        if (result == true)
        {
            // Open document
            string filename = dlg.FileName;
        }
    }
     public class ExcelData
{
    public DataView Data
    {
        get
        {
            Excel.Application excelApp = new Excel.Application();
            Excel.Workbook workbook;
            Excel.Worksheet worksheet;
            Excel.Range range;
            workbook = excelApp.Workbooks.Open(Environment.CurrentDirectory + "\\Excel.xlsx");
            worksheet = (Excel.Worksheet)workbook.Sheets["Test Sheet"];//.get_Item(1);

            int column = 0;
            int row = 0;
             range = worksheet.UsedRange;
            DataTable dt = new DataTable();
            dt.Columns.Add("ID");
            dt.Columns.Add("Name");
            dt.Columns.Add("Position");
            dt.Columns.Add("Web Site");
            for (row = 2; row <= range.Rows.Count; row++)
            {
             DataRow dr = dt.NewRow();
             for (column = 1; column <= range.Columns.Count; column++)
                {
             dr[column - 1] = (range.Cells[row, column] as Excel.Range).Value2.ToString();
                }
                dt.Rows.Add(dr);
                dt.AcceptChanges();
            }
            workbook.Close(true, Missing.Value, Missing.Value);
            excelApp.Quit();
            return dt.DefaultView;

        }

But it gave three errors (the underlined ones)
first two :"One or more types required to compiled a dynamic expression cannot be found"
last one : "The name "Missing" does not exist in the current context

Why i get those errors?

Thanks in advance.