decimal value = 0.00M;
value = Convert.ToDecimal(12345.12345);
Console.WriteLine(value.ToString("C"));
//OutPut : $12345.12
Console.WriteLine(value.ToString("C1"));
//OutPut : $12345.1
Console.WriteLine(value.ToString("C2"));
//OutPut : $12345.12
Console.WriteLine(value.ToString("C3"));
//OutPut : $12345.123
Console.WriteLine(value.ToString("C4"));
//OutPut : $12345.1234
Console.WriteLine(value.ToString("C5"));
//OutPut : $12345.12345
Console.WriteLine(value.ToString("C6"));
//OutPut : $12345.123450