Getting relative virtual path from physical path asp net c#

var relativePath = "/" + physicalPath.Replace(HttpContext.Current.Request.PhysicalApplicationPath, String.Empty).Replace("\\", "/");

Or use the extension method

/// <summary>
/// Get relative path from physical path
/// </summary>
/// <param name="di">DirectoryInfo</param>
/// <returns></returns>
public static string GetRelativePath(this DirectoryInfo di)
{
 return "/" + di.FullName.Replace(HttpContext.Current.Request.PhysicalApplicationPath, String.Empty).Replace("\\", "/");
}