How to rename a file in C# - asp.net

Question

Consider:
strPath= c:\images\gallery\add.gif
I need to rename this file from add.gif to thumb1.gid, and I should write one command method, whatever the file name. We need to
replace that name with this like below.
string strfilename = **"thumb"**
****Result thum.gif**
strPath= c:\images\gallery\thum.gif **

Answer 1

You have several problems, looking up the value in the XML file, and renaming the file.
To look up the number corresponding to Gallery2 or whatever, I would recommend having a look at Stack Overflow question How to implement a simple XPath lookup which explains how to look up nodes/values in an XML file.
To rename a file in .NET, use something like this:
using System.IO;
FileInfo fi = new FileInfo("c:\\images\\gallery\\add.gif");
if (fi.Exists)
{
fi.MoveTo("c:\\images\\gallery\\thumb3.gif");
}
Of course, you would use string variables instead of string literals for the paths.
That should give you enough information to piece it together and solve your particular lookup-rename problem.

Answer 2

I created a utility method to help encapsulate how to rename a file.
public class FileUtilities
{
public static void RenameFile(string oldFilenameWithPathWithExtension, string newFilenameWithoutPathWithExtension)
{
try
{
string directoryPath = Path.GetDirectoryName(oldFilenameWithPathWithExtension);
if (directoryPath == null)
{
throw new Exception($"Directory not found in given path value:{oldFilenameWithPathWithExtension}");
}
var newFilenameWithPath = Path.Combine(directoryPath, newFilenameWithoutPathWithExtension);
FileInfo fileInfo = new FileInfo(oldFilenameWithPathWithExtension);
fileInfo.MoveTo(newFilenameWithPath);
}
catch (Exception e)
{
//Boiler plate exception handling
Console.WriteLine(e);
throw;
}
}
}
I omitted several other file system checks that could optionally be done, but as #JoelCoehoorn pointed out in a comment on this page, the File System is Volatile, so wrapping it in a try-catch may be all that is necessary.
With that class in your library, now you can simply call:
var fullFilename = #"C:\images\gallery\add.gif";
var newFilename = "Thumb.gif";
FileHelper.RenameFile(fullFilename,newFilename);