How do I port an extension in VB.NET to C#?

Question

I wrote an extension in VB.NET for StringBuilder to add a AppendFormattedLine method (so I would not have to use one of the arguments for a new line character):

Imports System.Runtime.CompilerServices
Public Module sbExtension
    <Extension()> _
    Public Sub AppendFormattedLine(ByVal oStr As System.Text.StringBuilder, _
                                   ByVal format As String, _
                                   ByVal arg0 As Object)
        oStr.AppendFormat(format, arg0).Append(ControlChars.NewLine)
    End Sub
    <Extension()> _
    Public Sub AppendFormattedLine(ByVal oStr As System.Text.StringBuilder, _
                                   ByVal format As String, ByVal arg0 As Object, _
                                   ByVal arg1 As Object)
        oStr.AppendFormat(format, arg0, arg1).Append(ControlChars.NewLine)
    End Sub
    <Extension()> _
    Public Sub AppendFormattedLine(ByVal oStr As System.Text.StringBuilder, _
                                   ByVal format As String, _
                                   ByVal arg0 As Object, _
                                   ByVal arg1 As Object, _
                                   ByVal arg2 As Object)
        oStr.AppendFormat(format, arg0, arg1, arg2).Append(ControlChars.NewLine)
    End Sub
    <Extension()> _
   Public Sub AppendFormattedLine(ByVal oStr As System.Text.StringBuilder, _
                                  ByVal format As String, _
                                  ByVal ParamArray args() As Object)
        oStr.AppendFormat(format, args).Append(ControlChars.NewLine)
    End Sub
End Module

Answer 1

Here is the ported code that I came up with:

using System;
using System.Text;

public static class ExtensionLibrary
{
    public static void AppendFormattedLine(this StringBuilder sb, string format, object arg0)
    {
        sb.AppendFormat(format, arg0).Append(Environment.NewLine);
    }
    public static void AppendFormattedLine(this StringBuilder sb, string format, object arg0, object arg1)
    {
        sb.AppendFormat(format, arg0, arg1).Append(Environment.NewLine);
    }
    public static void AppendFormattedLine(this StringBuilder sb, string format, object arg0, object arg1, object arg2)
    {
        sb.AppendFormat(format, arg0, arg1, arg2).Append(Environment.NewLine);
    }
    public static void AppendFormattedLine(this StringBuilder sb, string format, params object[] args)
    {
        sb.AppendFormat(format, args).Append(Environment.NewLine);
    }
}

Hopefully this will come in useful for someone!

improved code, thanks joel, luke & jason.