[C#] DirectX AccesViolationException (Buffer)

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Diagnostics;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using Microsoft.DirectX;
using Microsoft.DirectX.Direct3D;

namespace WaveSim
{
 public partial class Form1 : Form
 {
 
 Functions fc = new Functions(); //instantiate the object for all required functions
 private Device dv; //DirectX device
 private CustomVertex.PositionColored[] vertices; //variable vertices
 static VertexBuffer vBuffer;
 

 
 public Form1()
 {
 InitializeComponent();
 }

 private void buttonBeenden_Click(object sender, EventArgs e)
 {
 Close(); //exit programm
 }

 private void buttonStart_Click(object sender, EventArgs e)
 {
 fc.Time = 0; 
 timer.Enabled = true;
 initGraphics(); //initialize graphics
 }

 private void buttonStop_Click(object sender, EventArgs e)
 {
 timer.Enabled = false;
 fc.GridAcceleration = fc.resetArray(fc.GridAcceleration); //reset all array to 0
 fc.GridSpeed = fc.resetArray(fc.GridSpeed);
 fc.GridZ = fc.resetArray(fc.GridZ);
 eraseDevice(); //erase 3D device from memory
 }

 private void trackBarFrequency_Scroll(object sender, EventArgs e)
 {
 fc.Periode = (1.0 / (trackBarFrequency.Value/100.0)); //Periode T = 1 / frequency
 showStatusInfo(); //show infos in status bar
 }

 private void trackBarAmplitude_Scroll(object sender, EventArgs e)
 {
 fc.Amplitude = trackBarAmplitude.Value; //assign the amplification from trackBarAmplitude
 showStatusInfo(); //show infos in status bar
 }

 private void trackBarDamping_Scroll(object sender, EventArgs e)
 {
 fc.Damping = trackBarDamping.Value / 1000.0d; //assign the damping from trackBarDamping
 showStatusInfo(); //show infos in status bar
 }

 private void Form1_Load(object sender, EventArgs e)
 {
 fc.Periode = 1.0d; //Default start with T = 1
 fc.Time = 0; //start time t=0
 timer.Interval = (int)( 1 * fc.Periode);
 fc.generateArrays();
 trackBarAmplitude.Value = (int)fc.Amplitude;
 labelX.Text = "X= " + fc.DimensionX.ToString();
 trackBarDimX.Value = fc.DimensionX;

 labelY.Text = "Y= " + fc.DimensionY.ToString();
 trackBarDimY.Value = fc.DimensionY;
 showStatusInfo(); //show infos in status bar
 }

 public void showStatusInfo()
 {
 //show actual values in the toolStrip at the bottom
 toolStripStatusLabelAmplitude.Text = "Amplitude: " + (fc.Amplitude).ToString();
 toolStripStatusLabelDamping.Text = "Dämpfungsfaktor: " + fc.Damping.ToString();
 toolStripStatusLabelFrequency.Text = "Frequenz: " + (1.0/fc.Periode).ToString() + "Hz";
 }

 private void timer_Tick(object sender, EventArgs e)
 {
 //wave(fc.Time); //create wave at time t
 fc.Time+=0.09f; //t = t + 1
 fc.calcWave(fc.Time);
 render();
 }

 private void trackBarLambda_Scroll(object sender, EventArgs e)
 {
 fc.Lambda = trackBarLambda.Value; //assign wavelength
 }

 public void initGraphics()
 {
 try
 {
 panelSimulation.ClientSize = new Size(600, 600);
 PresentParameters pp = new PresentParameters();
 pp.Windowed = true;
 pp.SwapEffect = SwapEffect.Copy;
 dv = new Device(Manager.Adapters.Default.Adapter, DeviceType.Hardware, panelSimulation, CreateFlags.HardwareVertexProcessing, pp);

 }
 catch (DirectXException e)
 {
 timer.Stop();
 MessageBox.Show(e.ToString());
 }
 }

 public void render()
 {
 dv.Transform.Projection = Matrix.PerspectiveFovLH(1f, 1, 1f, 10000f);
 dv.Transform.View = Matrix.LookAtLH(new Vector3((1000), (1000), 500), new Vector3(fc.DimensionX, fc.DimensionY, 0), new Vector3(0, 0, 1));
 dv.RenderState.Lighting = false;

 vertices = new CustomVertex.PositionColored[fc.DimensionX*fc.DimensionY];

 int i = 0;

 for (int x = 1; x < fc.DimensionX; x++)
 {
 for (int y = 1; y < fc.DimensionY; y++)
 {
 vertices[i].Position = new Vector3((float)x * 15, (float)y * 15, (float)fc.GridZ[x, y]);
 vertices[i].Color = Color.Green.ToArgb(); 
 i++;
 }
 }
 dv.VertexFormat = CustomVertex.PositionColored.Format;
 try
 {
 vBuffer = new VertexBuffer(typeof(CustomVertex.PositionColored),
 360,
 dv,
 Usage.WriteOnly,
 CustomVertex.PositionColored.Format,
 Pool.Default);
 vBuffer.SetData(vertices, 0, LockFlags.None);
 }
 catch (AccessViolationException e)
 {
 timer.Stop();
 MessageBox.Show(e.ToString());
 }
 dv.SetStreamSource(0, vBuffer, 0);
 dv.Clear(ClearFlags.Target, Color.Black, 1.0f, 0);
 dv.BeginScene();
 dv.DrawUserPrimitives(PrimitiveType.PointList, i, vertices); //draw 1 dot
 dv.EndScene();
 dv.Present();
 }


 public void eraseDevice()
 {
 dv.Dispose(); //delete Device
 }

 private void chkBorder_CheckedChanged(object sender, EventArgs e)
 {
 fc.FixedEdges = !fc.FixedEdges;
 }

 private void chkDouble_CheckedChanged(object sender, EventArgs e)
 {
 fc.DoubleSlit = !fc.DoubleSlit;
 }

 private void trackBarDimX_ValueChanged(object sender, EventArgs e)
 {
 fc.DimensionX = trackBarDimX.Value;
 fc.generateArrays();
 labelX.Text = "X= " + fc.DimensionX;
 }

 private void trackBarDimY_Scroll(object sender, EventArgs e)
 {
 fc.DimensionY = trackBarDimY.Value;
 fc.generateArrays();
 labelY.Text = "Y= " + fc.DimensionY;
 }

 }
}