Compiler Error CS1059
The operand of an increment or decrement operator must be a variable, property or indexer.
This error is raised when you try to increment or decrement a constant value. It can also occur if you try to increment an expression such as (a+b)++.
To correct this error
Make the variable non-const.
Remove the increment or decrement operator.
Store the expression in a variable, and then increment the variable.
Example
The following example generates CS1059 because i is a constant, not a variable, and E is an Enum type, whose elements are also constant values.
// CS1059.cs
class Program
{
public enum E : sbyte
{
a = 1,
b = 2
}
static void Main(string[] args)
{
const int i = 0;
i++; // CS1059
E test = E.a++; // CS1059
}
}