title: Non repeating random number in c# for Mine sweeper Game
body: <p>i am developing a mine sweeper game in c# of dimension (8 x 8).The difficulty levels increase/decrease the number of mines on the grid.</p>
  
  <p>I use a random class (with min,max set;) to generate a random cell number.The problem i am facing is ,the random object keeps repeating the same number.I tried to resolve this issue by maintaining a local list where i store the generated unique random numbers.The next time i call Next(), i would check it against the local list ,to see if its already present.If the number is already present i would keep calling Next() until  i get a new number which is unique and not present in the list.But this doesnt look in itself a good solution as sometimes it takes painful amount of time to generate a new list.</p>
  
  <p>Any suggestions on this please</p>