How to create a login command?

See more:

C#

XAML

MVVM

Hello,

how can i create a login command in mvvm with sql database account?

In normal wpf is the login button :

private void Login_Click(object sender, RoutedEventArgs e)
{
    if (txtUser.Text != "" && pwdUser.Password != "")
    {
        DBconnection objconn = new DBconnection();

        try
        {
            objconn.connection(); //calling connection

            SqlCommand com = new SqlCommand("Loginsp", objconn.con);
            com.CommandType = CommandType.StoredProcedure;
            com.Parameters.AddWithValue("@UserId", txtUser.Text);
            com.Parameters.AddWithValue("@password", pwdUser.Password);

            int IsValidUser = Convert.ToInt32(com.ExecuteScalar());
            if (IsValidUser == 1) //if user found it returns 1
            {
                MainWindow obj = new MainWindow();

                App.Current.MainWindow = obj;
                obj.Show(); //after login Redirect to second window
                this.Close();//after login hide the  Login window


            }
            else
            {

                MessageBox.Show("InValid UserId or Password");

            }
        }
        catch (Exception ex)
        {
            MessageBox.Show(ex.ToString());
        }
        finally
        {
            objconn.Close();
        }
    }
    else
    {

        MessageBox.Show("UserId and Password Is Required");

    }
}

Thanks.

What I have tried:

I have tried with delegate command and Relay command but he don't execute the command.