Coherent radiation from undulator beamlines has been used to directly measure the real and imaginary parts of the index of refraction of several materials at both extreme-ultraviolet and soft-x-ray wavelengths. Using the XOR interferometer, we measure the refractive indices of silicon and ruthenium, essential materials for extreme-ultraviolet lithography. Both materials are tested at wavelength \left(13.4\text{\hspace{0.17em} nm}\right) and across silicon's L_2\left(99.8\text{\hspace{0.17em} eV}\right) and L_{\text{3}}\left(99.2\text{\hspace{0.17em} eV}\right) absorption edges. We further extend this direct phase measurement method into the soft-x-ray region, where measurements of chromium and vanadium are performed around their L₃ absorption edges at 574.1 and \text{512.1 \hspace{0.17em} eV} , respectively. These are the first direct measurements, to our knowledge, of the real part of the index of refraction made in the soft-x-ray region.