Can not create if-else and else if statement on one line c#

I want to create a if else else if statement on one line but it does not work. Can somebody help me?

x = richtung == 7 ? x-- : richtung == 9 ? x++ : richtung == 3 ? x-- : richtung == 1 ? x++ : 0;
y = richtung == 7 ? y-- : richtung == 9 ? y-- : richtung == 3 ? y++ : richtung == 1 ? y++ : 0;