Restricting the number of digits after decimal

Question

For the purpose of limiting the number of digits after the decimal, I am doing the following in my webpage.

Single nnuma = Convert.ToSingle(dr["num1"].ToString());
Single numb = Convert.ToSingle(dr["num2"].ToString());

I have to restrict the number of digits after decimal to 3. How is this done here in Single data type?

Answer 1

maybe you can try this

nnuma.ToString ("#.###");
numb.ToString ("#.###");

Answer 2

You can try this. This will also properly precision the last digit, ie 0.6666 will be 0.667

decimal num = 20.123456789m;
Single x = Convert.ToSingle(String.Format("{0:00.000}", num));

Answer 3

Very Simple. Just Write # to Restrict digits after Decimal.

num.ToString("0.0000#") -- Restrict to 4 digits;

num.ToString("0.0#")-- Restrict to 1 digit;

Answer 4

The operation you are looking for is Math.Round :

Single unrounded = (Single)dr["num1"];  // change if the DB type is not a single
double rounded = Math.Round(unrounded, 3);
Single roundedSingle = (Single)rounded;

Math.Round returns a double when used with a Single, hence the need to convert to Single (float) afterwards. As a side note: You might want to consider using decimal s as an alternative, if decimal precision is an issue.

Note that this overload of Math.Round performs Banker's Rounding , ie, 0.0005 becomes 0.000 , but 0.0015 becomes 0.002 . If you want a different kind of rounding, use the Math.Round(Double, Int32, MidpointRounding) overload instead.

Answer 5

正则表达式始终是答案;）

var n = Regex.Replace(convertedToSingle.ToString(), @"([^.]*\.\d{0,3}).*", "$1");