Display Pictures from Folder in a List Box

Hi,

This is my code and I'm getting the error 'The name 'folderBrowserDialog1' does not exist in the current context' but I can't see why not and it's not pulling pictures from my picture folder.


using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.IO;
using System.Windows.Forms.FolderBrowserDialog;

namespace Pictures
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}

private void btnOpen_Click(object sender, EventArgs e)
{
if (folderBrowserDialog1.ShowDialog() == System.Windows.Forms.DialogResult.OK)
{

getPics(folderBrowserDialog1.SelectedPath);// getl list of files
}
}
public void getPics(string fPath)
{

foreach (string file in Directory.GetFiles(fPath))
{
if (checkIfimage(file))//check if file is image
{
listBox1.Items.Add(file);
}
}
}


public bool checkIfimage(string fname)
{
bool isImage = false;
string extension = Path.GetExtension(fname).ToLower();

if (extension == ".jpg" | extension == ".png" | extension == ".bmp")
{
isImage = true;
}
return isImage;
}
}
}

Can you help? Thanks