How to format floating point value with fix number of digits?

Question

Is it possible in C# to format a double value with double.ToString in a way that I have always a fixed number of digits, no matter on which side of the decimal point?

Sa

Answer 1

As I understand, there is no predefined format that does what I need. So for everyone who is interested, here is the function I ended up with:

public string FormatValue(double d, int noOfDigits)
    {
        double abs = Math.Abs(d);
        int left = abs < 1 ? 1 : (int)(Math.Log10(abs) + 1);

        int usedDigits = 0;

        StringBuilder sb = new StringBuilder();
        for(; usedDigits < left; usedDigits++)
        {
            sb.Append("0");
        }
        if(usedDigits < noOfDigits)
        {
            sb.Append(".");
            for(; usedDigits < noOfDigits; usedDigits++)
            {
                sb.Append("0");
            }
        }
        return d.ToString(sb.ToString());
    }