//Change your thread initialization to:
var t = new Thread(new ParameterizedThreadStart(myMethod));
t.Start(myGrid);
//And also the method to:
public void myMethod(object myGrid)
{
var grid = (UltraGrid)myGrid;
}
//Pass Parameters to thread without using PARMETERIZED THREAD START
public void myMethod(UltraGrid myGrid, string s)
{
}
Thread t = new Thread(()=>myMethod(myGrid, "abc"));
t.Start();