Getting the relative path to the rdlc report in my winform app

Use the Application.StartupPath property, it always points to directory where your EXE is located:

  using System.IO;
  ...

     string exeFolder = Application.StartupPath;
     string reportPath = Path.Combine(exeFolder, @"Reports\report.rdlc");

You'll want to make sure the report gets copied to your bin\Debug\Reports folder as well so it will work in the IDE. Use xcopy /s /d in a post-build event to get the file(s) copied.