Insert and update in sql table using datagrid in WPF.

Here i have done insert and update operation using sp in datagrid...
But I am getting an error ...No mapping exists from object type System.Windows.Controls.DataGridTextColumn to a known managed provider native type.'

Can AnyOne Solve This Problem?
Thank You ..

namespace DataGrid_StoreProcedure
{
///

/// Interaction logic for MainWindow.xaml
///

public partial class MainWindow : Window
{
string cs = ConfigurationManager.ConnectionStrings["DBMS"].ConnectionString;

public MainWindow()
{
InitializeComponent();
}

private void Window_Loaded(object sender, RoutedEventArgs e)
{



PopulateDatagrid();


}

void PopulateDatagrid()
{

using (SqlConnection con = new SqlConnection(cs))
{

con.Open();
SqlDataAdapter sda = new SqlDataAdapter("SELECT * from Emp", con);
DataTable dt = new DataTable();
sda.Fill(dt);
Mydg.ItemsSource = dt.AsDataView();


}
}

private void Mydg_RowEditEnding(object sender, DataGridRowEditEndingEventArgs e)
{


if (Mydg.SelectedIndex == 0)
{
using (SqlConnection con = new SqlConnection(cs))
{
con.Open();

SqlCommand cmd = new SqlCommand("SPemployee", con);
cmd.CommandType = CommandType.StoredProcedure;
cmd.Parameters.AddWithValue("@Action", "INSERT");
cmd.Parameters.AddWithValue("@EmployeeId", 0);
cmd.Parameters.AddWithValue("@FirstName", FirstName);
cmd.Parameters.AddWithValue("LastName", LastName);
cmd.Parameters.AddWithValue("@Age", Age);
cmd.Parameters.AddWithValue("@IsAvailable", IsAvailable);
cmd.ExecuteNonQuery();
con.Close();

}
}
else
{
using (SqlConnection con = new SqlConnection(cs))
{
con.Open();
SqlCommand cmd = new SqlCommand("SPemployee", con);
cmd.CommandType = CommandType.StoredProcedure;
cmd.Parameters.AddWithValue("@Action", "UPDATE");
cmd.Parameters.AddWithValue("@EmployeeId", SqlDbType.Int).Value = EmployeeId;
cmd.Parameters.AddWithValue("@FirstName", SqlDbType.NVarChar).Value = FirstName;
cmd.Parameters.AddWithValue("LastName", SqlDbType.NVarChar).Value = LastName;
cmd.Parameters.AddWithValue("@Age", SqlDbType.Int).Value = Age;
cmd.Parameters.AddWithValue("@IsAvailable", SqlDbType.Bit).Value = IsAvailable;
cmd.ExecuteNonQuery();




}


}


PopulateDatagrid();





}
}
}