public class Combination
{
List innerArray_ = new List();

public Combination()
{
this.DigitCount = 0;
this.Combinations = 0;
}

public int DigitCount { get; set; }

public int Combinations { get; set; }

public List GetCombinations()
{
if (DigitCount > 0)
{
//for (int i = 0; i < this.DigitCount; i++)
// GetCombinations(i.ToString(), i);

GetCombinations("", -1);
}

return this.innerArray_;
}

public List GetCombinations(int digitcount, int combinations)
{
this.DigitCount = digitcount;
this.Combinations = combinations;

return this.GetCombinations();
}

///
/// Kombinasyon hesaplamasını yapar
///
/// <param name="current">Şu anki işlenen veri</param>
/// <param name="index">İşlenen veri indexi</param>
private void GetCombinations(string current, int index)
{
string tmpcurrent = "";

for (int i = index + 1; i < this.DigitCount; i++)
{
tmpcurrent = current + i.ToString();

GetCombinations(tmpcurrent, i);
}

if (current.Length == this.Combinations)
this.innerArray_.Add(current);
}
}

Combination com = new Combination();

List result = com.GetCombinations(5, 2);