would remove a key from Dictionary in foreach cause a problem? or should I better to construct a new Dictionary?

Question

for example:

1.

         foreach (var item in myDic)
                {
                  if (item.value == 42)
                        myDic.remove(item.         


        

Answer 1

Also you can iterate over the copy of your collection:

foreach (var item in myDic.ToList())
{
    if (item.value == 42)
    myDic.remove(item.key);
}

notice myDic.ToList() in foreach statement.