C # помочь объявить переменную я инициализировать его

Я посмотрел на источник, который вы опубликовали, и он работает для меня. Вот код:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Runtime.InteropServices;
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.Interop;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Shapes;

namespace PAUL.Allgemein.Seiten
{
/// <summary>
/// Interaktionslogik für Robbe.xaml
/// </summary>
public partial class Robbe : Window
{
    #region The Classic Window API
    //The SendMessage function sends a message to a window or windows.
    [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = false)]
    static extern IntPtr SendMessage(IntPtr hWnd, uint Msg, int wParam, int lParam);

    //ReleaseCapture releases a mouse capture
    [DllImportAttribute("user32.dll", CharSet = CharSet.Auto, SetLastError = false)]
    public static extern bool ReleaseCapture();

    //SetWindowLong lets you set a window style
    [System.Runtime.InteropServices.DllImport("user32.dll")]
    static extern int SetWindowLong(IntPtr hWnd, int nIndex, long dwNewLong);
    #endregion

    const int GWL_STYLE = -16;
    const long WS_POPUP = 2147483648;

    //private const int GWL_STYLE = -16;
    //private const int WS_SYSMENU = 0x80000;
    //[DllImport("user32.dll", SetLastError = true)]
    //private static extern int GetWindowLong(IntPtr hWnd, int nIndex);
    //[DllImport("user32.dll")]
    //private static extern int SetWindowLong(IntPtr hWnd, int nIndex, int dwNewLong);
    public Robbe()
    {

        InitializeComponent();
    }

    private void Window_Loaded(object sender, RoutedEventArgs e)
    {
        IntPtr hWnd = new System.Windows.Interop.WindowInteropHelper(this).Handle;
        SetWindowLong(hWnd, GWL_STYLE, WS_POPUP);
    }
}
}

xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="Robbe" Height="300" Width="300"
    Loaded="Window_Loaded">
<Grid>
    <!-- Creates the shadow on the right and bottom -->
    <Border Focusable="False" BorderBrush="Gray"           
        BorderThickness="0,0,2,2"
        CornerRadius="10"
        Background="Beige" >
        <WebBrowser Source="C:\Users\nicholas\Desktop\puale\PAUL\bin\Debug\robbe.swf" Margin="62,71,69,56"></WebBrowser>
    </Border>
</Grid>