Question

I have an instance of StringBuilder in my C# application wherein I would like certain lines to be padded with a varying number of spaces depending on the context. My usage is very simple:

StringBuilder MyStringBuilder = new StringBuilder();
MyStringBuilder.AppendFormat("{0:" + this._padding + "}"); // <-- Exception thrown here
MyStringBuilder.AppendLine("My data.");

If this._padding==10, the resulting output should look something like this:

     My data.

How can I pad my strings without resorting to using a for loop? Thanks.

ADDITIONAL INFO

Exception: “Index (zero based) must be greater than or equal to zero and less than the size of the argument list.”

Answer 1

• You need to provide both the format and the arguments in one call.
• To pad left you use {0,10}, not {0:10}.

Try this:

MyStringBuilder.AppendFormat("{0," + this._padding + "}", "My Data");

There is also a string.PadLeft method that you could use.

MyStringBuilder.Append("My Data".PadLeft(this._padding));