The theoretical fundamentals for the calculation of the local cathodoluminescence (CL) signal and electron beam induced current (EBIC) in the scanning electron microscoe (SEM) are outlined. Especially, the simulation of the signal contrast profile behavior of individual dislocation configurations is reviewed. Existing analytical models and new numerical approaches are summarized. Besides the evaluation of material parameters, the conception of combined SEM-CL/EBIC is applied for the quantitative experimental characterization of single defects in grown-in, misfit as well as glide dislocation structures with respect to their recombination activiy in various III-V semiconductors. Recent CL data from dislocations in GaPm GaAs, and CdTe in the low-temperature range are analyzed in the framework of temperature-dependent defect-related recombination kinetics.