C# convert int to string with padding zeros?
i.ToString().PadLeft(4, '0')
- okay, but doesn't work for negative numbers
i.ToString("0000");
- explicit form
i.ToString("D4");
- short form format specifier
$"{i:0000}";
- string interpolation (C# 6.0+)
i.ToString("D4");
See MSDN on format specifiers.
Here's a good example:
int number = 1;
//D4 = pad with 0000
string outputValue = String.Format("{0:D4}", number);
Console.WriteLine(outputValue);//Prints 0001
//OR
outputValue = number.ToString().PadLeft(4, '0');
Console.WriteLine(outputValue);//Prints 0001 as well