.NET Format a string with fixed spaces

Question

This will give you exactly the strings that you asked for:

string s = "String goes here";
string lineAlignedRight  = String.Format("{0,27}", s);
string lineAlignedCenter = String.Format("{0,-27}",
    String.Format("{0," + ((27 + s.Length) / 2).ToString() +  "}", s));
string lineAlignedLeft   = String.Format("{0,-27}", s);

As of Visual Studio 2015 you can also do this with Interpolated Strings (its a compiler trick, so it doesn't matter which version of the .net framework you target).

string value = "String goes here";
string txt1 = $"{value,20}";
string txt2 = $"{value,-20}";

The first and the last, at least, are possible using the following syntax:

String.Format("{0,20}", "String goes here");
String.Format("{0,-20}", "String goes here");

You've been shown PadLeft and PadRight. This will fill in the missing PadCenter.

public static class StringUtils
{
    public static string PadCenter(this string s, int width, char c)
    {
        if (s == null || width <= s.Length) return s;

        int padding = width - s.Length;
        return s.PadLeft(s.Length + padding / 2, c).PadRight(width, c);
    }
}

Note to self: don't forget to update own CV: "One day, I even fixed Joel Coehoorn's code!" ;-D -Serge

try this:

"String goes here".PadLeft(20,' ');
"String goes here".PadRight(20,' ');

for the center get the length of the string and do padleft and padright with the necessary characters

int len = "String goes here".Length;
int whites = len /2;
"String goes here".PadRight(len + whites,' ').PadLeft(len + whites,' ');

Thanks for the discussion, this method also works (VB):

Public Function StringCentering(ByVal s As String, ByVal desiredLength As Integer) As String
    If s.Length >= desiredLength Then Return s
    Dim firstpad As Integer = (s.Length + desiredLength) / 2
    Return s.PadLeft(firstpad).PadRight(desiredLength)
End Function

1. StringCentering() takes two input values and it returns a formatted string.
2. When length of s is greater than or equal to deisredLength, the function returns the original string.
3. When length of s is smaller than desiredLength, it will be padded both ends.
4. Due to character spacing is integer and there is no half-space, we can have an uneven split of space. In this implementation, the greater split goes to the leading end.
5. The function requires .NET Framework due to PadLeft() and PadRight().
6. In the last line of the function, binding is from left to right, so firstpad is applied followed by the desiredLength pad.

Here is the C# version:

public string StringCentering(string s, int desiredLength)
{
    if (s.Length >= desiredLength) return s;
    int firstpad = (s.Length + desiredLength) / 2;
    return s.PadLeft(firstpad).PadRight(desiredLength);
}

To aid understanding, integer variable firstpad is used. s.PadLeft(firstpad) applies the (correct number of) leading white spaces. The right-most PadRight(desiredLength) has a lower binding finishes off by applying trailing white spaces.

Here's a VB.NET version I created, inspired by Joel Coehoorn's answer, Oliver's edit, and shaunmartin's comment:

    <Extension()>
Public Function PadCenter(ByVal [string] As String, ByVal width As Integer, ByVal c As Char) As String

    If [string] Is Nothing Then [string] = String.Empty
    If (width <= [string].Length) Then Return [string]

    Dim padding = width - [string].Length
    Return [string].PadLeft([string].Length + (padding \ 2), c).PadRight(width, c)

End Function

<Extension()>
Public Function PadCenter(ByVal [string] As String, ByVal width As Integer) As String

    If [string] Is Nothing Then [string] = String.Empty
    If (width <= [string].Length) Then Return [string]

    Dim padding = width - [string].Length
    Return [string].PadLeft([string].Length + (padding \ 2)).PadRight(width)

End Function

This is set up as a string extension, inside a Public Module (the way you do Extensions in VB.NET, a bit different than C#). My slight change is that it treats a null string as an empty string, and it pads an empty string with the width value (meets my particular needs). Hopefully this will convert easily to C# for anyone who needs it. If there's a better way to reference the answers, edits, and comments I mentioned above, which inspired my post, please let me know and I'll do it - I'm relatively new to posting, and I couldn't figure out to leave a comment (might not have enough rep yet).