thread safety - Invoke: how can I assign UI obj from BackgroundWorker? C# -

here core of code. i've tried invoke every way china, same big red x , objectdisposed exception on form1. (edited out unrelated code brevity.)

using system; using system.globalization; using system.componentmodel; using system.collections.generic; using system.drawing; using system.io; using system.windows.forms; using knowncolorspalette;  namespace color_visualizer {     public partial class form1 : form     {         static cultureinfo m_culture = cultureinfo.currentculture;         fastpixel m_fp; // fastpixel encapsulates                          // bitmap.lockbits() funcs & data          private void backgroundworker1_dowork(object sender, system.componentmodel.doworkeventargs e)         {             double fangle, fradius, d;             point3d vu, vv;             point plocation = new point();                          {                 m_pnormal = coord.plane.normal;                  fangle = math.atan2(m_pnormal.y, m_pnormal.x);                 fradius = math.sqrt(m_pnormal.x * m_pnormal.x + m_pnormal.y * m_pnormal.y);                 fangle += fspeed * 180 / math.pi;                 m_pnormal.x = math.cos(fangle) * fradius;                 m_pnormal.y = math.sin(fangle) * fradius;                  m_fp.lock();                 m_fp.clear(color.black);                 foreach (foundcolors fc in m_lcolors.values)                 {                     vu = new point3d(coord.u);                     d = dist(fc.pt, ref vu);                     vv = coord.v;                     vv.mult(d);                      plocation.x = (int)(m_midhoriz + vu.norm());                     plocation.y = (int)(m_midvert + vv.norm());                     m_fp.setpixel(plocation, fc.color);                 }                 m_fp.unlock();                 invoke((methodinvoker)delegate { picturebox1.image = m_fp.bitmap; });             } while (true);         }           public form1()         {             initializecomponent();             windowstate = formwindowstate.maximized;             coordinatesystem.assignme(this);         }          void readcolors() // saved of wikipedia's 1200+ named colors         {                 // text file.         }          private void form1_load(object sender, eventargs e)         {             readcolors();              point3d p = new point3d(127.5, 127.5, 127.5);             foreach (foundcolors fc in m_lcolors.values)                 fc.pt = fc.color - p; // point3d class has                             // implicit operator casts ,                            // color.              coord = new coordinatesystem(new plane(new point3d(-127.5, -127.5, -127.5), new point3d(-1, 0, 0)));             backgroundworker1.runworkerasync();         }           double fspeed = 5;         point3d m_pnormal = new point3d();          double m_fdist, m_fdot;         public double dist(point3d pt, ref point3d vu)         {             double c1 = pt.dot(vu);             double c2 = vu.dot(vu);             double b = c1 / c2;             vu.mult(b);             //m_fdot = pt.dot(coord.normal);             m_fdist = pt.norm(pt - vu);             return m_fdist;         }          double m_midhoriz, m_midvert;         private void form1_resize(object sender, eventargs e)         {             m_midhoriz = picturebox1.width / 2;             m_midvert = picturebox1.height / 2;             m_fp = new fastpixel(new bitmap(picturebox1.width, picturebox1.height));         }     } } 

this support code, not central question: sorting.cs

using system.collections.generic; using system.drawing; using system.diagnostics; using system.windows.forms; using knowncolorspalette;  namespace color_visualizer {     public partial class form1 : form     {         public static colorcomp m_compclr = new colorcomp();         public static namecomp m_compname = new namecomp();         sortedlist<color, foundcolors> m_lcolors = new sortedlist<color, foundcolors>(m_compclr);         sortedlist<string, foundcolors> m_lcolorbyname = new sortedlist<string, foundcolors>(m_compname);          [debuggerdisplayattribute("{name}, r={color.r}, g={color.g}, b={color.b}")]         class foundcolors         {             public color color = color.empty;             public string name = "";             public cielab_color clab;             public point3d pt;             public list<int> lclosest = new list<int>();             public int nfarthest;             public foundcolors(foundcolors fc)             {                 color = fc.color;                 name = fc.name;                 clab = new cielab_color(fc.clab.cie_l, fc.clab.cie_a, fc.clab.cie_b);                 lclosest.addrange(fc.lclosest);                 nfarthest = fc.nfarthest;             }             public foundcolors() { }         }           struct sort         {             public double dist;             public int index;             public sort(double _d, int _i) { dist = _d; index = _i; }         }          class distcomp : icomparer<sort>         {             int icomparer<sort>.compare(sort x, sort y)             {                 if ((object)x == null)                     if ((object)y == null)                         return 0;                     else                         return -1;                  if ((object)y == null) return 1;                  if (x.dist > y.dist) return -1;                  return 1;             }         }           public class namecomp : icomparer<string>         {             int icomparer<string>.compare(string x, string y)             {                 if ((object)x == null)                     if ((object)y == null)                         return 0;                     else                         return -1;                  if ((object)y == null) return 1;                  return x.compareto(y);             }         }          public class colorcomp : icomparer<color>         {             int icomparer<color>.compare(color x, color y)             {                 if ((object)x == null)                     if ((object)y == null)                         return 0;                     else                         return -1;                  if ((object)y == null) return 1;                  if (x.r > y.r)                     return -1;                 else if (x.r < y.r)                     return 1;                 else if (x.g > y.g)                     return -1;                 else if (x.g < y.g)                     return 1;                 else if (x.b > y.b)                     return -1;                 else if (x.b < y.b)                     return 1;                  return 0;             }         }     } } 

and lastly more support code, coordinatesystem.cs:

using system; using system.drawing; using system.diagnostics; using system.windows.forms;  namespace color_visualizer {      public partial class form1 : form     {         class coordinatesystem         {             const int max = 256;             const double planewidth = 600;              static form1 me;             static point3d axisz = new point3d(0, 0, 1);             static point3d axisy = new point3d(0, 1, 0);             private plane m_plane = new plane(new point3d(128, 128, 128), new point3d(-128, 0, 0));             private point3d m_pv = new point3d(0, 0, 0);             private point3d m_pu = new point3d(0, 0, 0);             private double m_finc;              public coordinatesystem(plane axaxis)             {                 m_finc = planewidth / me.clientsize.height;                 plane = axaxis;             }             public static void assignme(form1 form) { me = form; }             public point3d u { { return m_pu; } protected set { m_pu = value; } }             public point3d v { { return m_pv; } protected set { m_pv = value; } }             public point3d normal { { return m_plane.normal; } set { m_plane.normal = value; } }             static double coserror = 0.99619469809174553229501040247389;              public plane plane             {                  { return m_plane; }                 set {                     m_plane = value;                     if (m_plane.dot(axisz) > coserror)                         u = u.cross(m_plane, axisy);                     else                         u = u.cross(m_plane, axisz);                     u.div(u.norm());                     v = u.cross(u, m_plane);                     v.div(v.norm());                 }             }         }          [debuggerdisplayattribute("x = {x}, y = {y}, z = {z}")]         public class point3d         {             public double x, y, z;              public point3d(double _x, double _y, double _z) { x = _x; y = _y; z = _z; }             public point3d(point3d p) { x = p.x; y = p.y; z = p.z; }             public point3d() { x = 0; y = 0; z = 0; }             public bool equals(point3d p) { return x == p.x & y == p.y & z == p.z; }             public override bool equals(object obj) { return equals((point3d)obj); }             public static bool operator ==(point3d p1, point3d p2) { return p1.equals(p2); }             public static bool operator !=(point3d p1, point3d p2) { return !p1.equals(p2); }             public static point3d operator -(point3d e, point3d s) { return new point3d(e.x - s.x, e.y - s.y, e.z - s.z); }             public static point3d operator +(point3d e, point3d s) { return new point3d(e.x + s.x, e.y + s.y, e.z + s.z); }             public static point3d operator *(double m, point3d v) { return new point3d(m * v.x, m * v.y, m * v.z); }             public static point3d operator *(point3d v, double m) { return new point3d(v.x / m, v.y / m, v.z / m); }             public static point3d operator /(double m, point3d v) { return new point3d(m * v.x, m * v.y, m * v.z); }             public static point3d operator /(point3d v, double m) { return new point3d(v.x / m, v.y / m, v.z / m); }             public static implicit operator color(point3d p) { return color.fromargb((int)p.x, (int)p.y, (int)p.z); }             public static implicit operator point3d(color c) { return new point3d(c.r, c.g, c.b); }             //public override int gethashcode()             //{             //    unchecked             //    {             //        var hash = new spookyhash();             //        hash.update(x);             //        hash.update(y);             //        hash.update(z);             //        return hash.final().gethashcode();             //    }             //}              // dot product (3d) allows vector operations in arguments             public double dot(point3d u, point3d v) { return u.x * v.x + u.y * v.y + u.z * v.z; }             public double dot(point3d u) { return u.x * x + u.y * y + u.z * z; }             public double norm(point3d v) { return math.sqrt(dot(v, v)); }     // norm = length of  vector             public double norm() { return math.sqrt(dot(this, this)); }     // norm = length of  vector             public double dist(point3d u, point3d v) { return norm(u - v); }         // distance = norm of difference             public double dist(point3d u) { return norm(this - u); }             public point3d cross(point3d u, point3d v) { return new point3d(u.y * v.z - u.z * v.y, u.z * v.x - u.x * v.z, u.x * v.y - u.y * v.x); }             public point3d cross(point3d u) { return new point3d(u.y * z - u.z * y, u.z * x - u.x * z, u.x * y - u.y * x); }             public void add(point3d p) { x += p.x; y += p.y; z += p.z; }             public void mult(double m) { x *= m; y *= m; z *= m; }             public void div(double m) { x /= m; y /= m; z /= m; }         }           class plane : point3d         {             point3d m_pnormal;              public plane(point3d porigin, point3d pnormal) : base(porigin) { m_pnormal = pnormal; }             public plane(point3d p) : base(p) { }             public plane(double x, double y, double z) : base(x, y, z) { }             public point3d normal { { return m_pnormal; } set { m_pnormal = value; } }             public double pointtoplane(point3d p) { return p.dot(normal); }         }           private coordinatesystem m_coordsys;         private coordinatesystem coord         {             { return m_coordsys; }             set { m_coordsys = value; }     } } 

only 1st code segment genuinely relevant question, know ask it, included of supporting code.

note have tried such things diverse progresschanged event (after enabling in properties of course) , various forms of delegates. use simple matter old delegates, spent 10 hours today no success, , never fail find working code examples, if have wade thru dozens of inferior answers. there utter profusion of contradictory answers question depending on date of post , kind of approach suggested.

the invoke method work if thread.sleep() 200ms. haven't tested lower limit, won't consistent across machines, reporting won't informative.