There is a predefined implicit conversion from ushort to int, uint, long, ulong, float, double, or decimal.
There is a predefined implicit conversion from byte or char to ushort. Otherwise a cast must be used to perform an explicit conversion. Consider, for example, the following two ushort variables x and y:
The following assignment statement will produce a compilation error, because the arithmetic expression on the right-hand side of the assignment operator evaluates to int by default.
ushort z = x + y; // Error: conversion from int to ushort
To fix this problem, use a cast:
ushort z = (ushort)(x + y); // OK: explicit conversion
It is possible though to use the following statements, where the destination variable has the same storage size or a larger storage size:
int m = x + y;
long n = x + y;
Notice also that there is no implicit conversion from floating-point types to ushort. For example, the following statement generates a compiler error unless an explicit cast is used:
// Error -- no implicit conversion from double:
ushort x = 3.0;
// OK -- explicit conversion:
ushort y = (ushort)3.0;
For information on arithmetic expressions with mixed floating-point types and integral types, see float and double.
For more information on implicit numeric conversion rules, see the Implicit Numeric Conversions Table (C# Reference).