C#

Luc Pattyn wrote:

I think you have to expand on the specifications.

public static string MakeRelativePath(string refPath, string targetPath) {
    string[] parts1=Path.GetFullPath(refPath).Split('\\');
    string[] parts2=Path.GetFullPath(targetPath).Split('\\');

    int i=0;
    for (; i<parts1.Length && i<parts2.Length; i++) {
        if (string.Compare(parts1[i], parts2[i])!=0) break;
    }
    string result="";
    for (int j=i; j<parts1.Length; j++) result+="..\\";
    result+=string.Join('\\', i, parts2.Length-i);
    return result;
}

public const int MAX_PATH = 260;
public const uint FILE_ATTRIBUTE_DIRECTORY = 0x10;
internal const string SHLWAPI = "shlwapi.dll";
 
[DllImport(SHLWAPI, CharSet = CharSet.Unicode)]
[return: MarshalAsAttribute(UnmanagedType.Bool)]
[ResourceExposure(ResourceScope.None)]
internal static extern bool PathRelativePathTo([MarshalAsAttribute(UnmanagedType.LPWStr)] StringBuilder pszPath, [MarshalAsAttribute(UnmanagedType.LPWStr), In] string pszFrom, uint dwAttrFrom, [MarshalAsAttribute(UnmanagedType.LPWStr), In] string pszTo, uint dwAttrTo);
 
[DllImport(SHLWAPI, CharSet = CharSet.Unicode)]
[return: MarshalAsAttribute(UnmanagedType.Bool)]
[ResourceExposure(ResourceScope.None)]
internal static extern bool PathIsDirectoryEmpty([MarshalAsAttribute(UnmanagedType.LPWStr), In] string pszPath);
 
/// <summary>
/// Creates a relative path from one file or folder to another.
/// </summary>
/// <param name="from">Contains the directory that defines the start of 
/// the relative path.</param>
/// <param name="to">Contains the path that defines the endpoint of the 
/// relative path.</param>
/// <returns>The relative path from the start directory to the end 
/// path.</returns>
public static string PathRelativePathTo(string from, string to)
{
    string result = String.Empty;
    StringBuilder path = new StringBuilder(MAX_PATH);
    uint fromAttributes = IsDirectory(from) ? FILE_ATTRIBUTE_DIRECTORY : 0;
    uint toAttributes = IsDirectory(to) ? FILE_ATTRIBUTE_DIRECTORY : 0;
 
    if (PathRelativePathTo(path, from, fromAttributes, to, toAttributes))
    {
	result = path.ToString();
    }
 
    return result;
}
 
/// <summary>
/// Verifies that a path is a valid directory.
/// </summary>
/// <param name="path">The path to verify.</param>
/// <returns><see langword="true"/> if the path is a valid directory; 
/// otherwise, <see langword="false"/>.</returns>
public static bool IsDirectory(string path)
{
    return PathIsDirectory(path);
}

if(isDirty)
{
  MessageBox.Show("Please save first");
}
else
{
  // Print here
}