how to resolve relative path in c#

Question

i have a function which combine path. Example

My application is located in D:\toto\titi\tata\myapplication.exe

And I create a windows form application(c#) which solve the relative path based on the path of my application (D:\toto\titi\tata\myapplication.exe).

I want to this this :

1)Path to resolve is test.txt => D:\toto\titi\tata\test.txt

2)Path to resolve is .\..\..\test\test.txt => D:\toto\test\test.txt

3)Path to resolve is .\..\test\test.txt => D:\toto\titi\test\test.txt

4)Path to resolve is .\..\..\..\test\test.txt => D:\test\test.txt

5)Path to resolve is .\..\..\..\..\test\test.txt => The path doesn't exist

6)Path to resolve is \\server\share\folder\test => get the corresponding path in the server.

I use this method

private void btnSearchFile_Click(object sender, EventArgs e)
{
    // Open an existing file, or create a new one.
    FileInfo fi = new FileInfo(@"D:\toto\titi\tata\myapplication.exe");

    // Determine the full path of the file just created or opening.
    string fpath = fi.DirectoryName;

    // First case.
    string relPath1 = txtBoxSearchFile.Text;
    FileInfo fiCase1 = new FileInfo(Path.Combine(fi.DirectoryName, relPath1.TrimStart('\\')));

    //Full path
    string fullpathCase1 = fiCase1.FullName;

    txtBoxFoundFile.Text = fullpathCase1;
}

but i doesn't solve point 1);point 5) and point 6)

Can you help me

Answer 1

You can get the current directory with Environment.CurrentDirectory.

To convert from relative paths to absolut paths you can do this:

var currentDir = @"D:\toto\titi\tata\";
var case1 = Path.GetFullPath(Path.Combine(currentDir, @"test.txt"));
var case2 = Path.GetFullPath(Path.Combine(currentDir, @".\..\..\test\test.txt"));
var case3 = Path.GetFullPath(Path.Combine(currentDir, @".\..\test\test.txt"));
var case4 = Path.GetFullPath(Path.Combine(currentDir, @".\..\..\..\test\test.txt"));
var case5 = Path.GetFullPath(Path.Combine(currentDir, @".\..\..\..\..\test\test.txt"));
var case6 = Path.GetFullPath(Path.Combine(currentDir, @"\\server\share\folder\test".TrimStart('\\')));

And to check the existance of a specified file:

if (File.Exists(fileName))
{
  // ...
}

So to conclude you can rewrite your method to something like this (if I understand your question correctly):

private void btnSearchFile_Click(object sender, EventArgs e)
{
  var currentDir = Environment.CurrentDirectory;
  var relPath1 = txtBoxSearchFile.Text.TrimStart('\\');
  var newPath = Path.GetFullPath(Path.Combine(currentDir, relPath1));
  if (File.Exists(newPath))
    txtBoxFoundFile.Text = newPath;
  else
    txtBoxFoundFile.Text = @"File not found";
}