- The deceptively simple ToString() method accepts an optional string as argument, called the "format provider": .NET will do its best to make the string match the (rudimentary) pattern you supplied. Applied on numbers, this is an easy way to "pretty-format" them for human consumption.
- Here's code that adds a zero in front of the current month: (use same technique for day's date)
string str = DateTime.Now.Month.ToString("00");
MessageBox.Show( "Current month is: " + str ); // 01, 02 ... 11, 12
- That same approach can be used to format currency numbers / decimals. Here's how you ensure that 2 decimals always show, regardless of the number of digits actually stored after the period:
double tip = 5; // no decimals
MessageBox.Show( "Your tip should be $" + tip.ToString("0.00") ); // $5.00
tip = 5.1; // one decimal
MessageBox.Show( "Your tip should be $" + tip.ToString("0.00") ); // $5.10 - You can also use the ToString() method to round off decimals: (cents, in our case)
tip = 5.135; // three decimals, unrounded -> ToString() method will round!
MessageBox.Show( "Your tip should be $" + tip.ToString("0.00") ); // $5.14Note - .NET is smart enough not to truncate the integer part to fit your format provider:
tip = 123.4; // three digits before decimal point
MessageBox.Show( "Tip should be $" + tip.ToString("0.00") ); // $123.40 - Bonus tip - you can specify the thousands separator (space / comma) in your format provider:
double num = 1234.5;
// Separate thousands with a comma (US and Canada)
string northAmStyle = num.ToString("0,000.00");
// Separate thousands with a space (most of Europe)
string euroStyle = num.ToString("0 000.00");
MessageBox.Show( "Here are your pretty numbers:\n" +
northAmStyle +" and "+ euroStyle );
Email AOL Mail Gmail Hotmail Yahoo Mail MS Office Excel 2010 OneNote 2010 Outlook 2010 Word 2010 OS & Devices Kindle Fire Windows 7 Web Dev C# and .NET JavaScript jQuery