Why would a country give another country financial assistance but require that capital projects using that money be contracted with granting country

Foreign aid and national borrowing are some of the ways in which a country can be assisted financially. According to countries offering financial assistance, it is a form of investment while to the countries at the receiving end, it is a source of capital. For it to be a win-win situation, projects emerging from the capital should be contracted with the granting country as a form of appreciation.