how to make relative path file in c# code example

Example 1: c# relative path to project folder

string fileName = "ich_will.mp3";
string path = Path.Combine(Environment.CurrentDirectory, @"Data\", fileName);

Example 2: how to get relative path in c#

Uri file = new Uri(@"c:\foo\bar\blop\blap.txt");
// Must end in a slash to indicate folder
Uri folder = new Uri(@"c:\foo\bar\");
string relativePath = 
Uri.UnescapeDataString(
    folder.MakeRelativeUri(file)
        .ToString()
        .Replace('/', Path.DirectorySeparatorChar)
    );