() Operator (C# Reference)
In addition to being used to specify the order of operations in an expression, parentheses are used to specify casts, or type conversions:
double x = 1234.7;
int a;
a = (int)x; // cast double to int
Remarks
A cast explicitly invokes the conversion operator from one type to another; the cast will fail if no such conversion operator is defined. To define a conversion operator, see explicit and implicit.
The () operator cannot be overloaded.
For more information, see Casting (C# Programming Guide).
A cast expression can lead to ambiguous syntax. For example, the expression (x)–y could either be interpreted as a cast expression (a cast of –y to type x) or as an additive expression combined with a parenthesized expression, which computes the value x – y.
C# Language Specification
For more information, see the following sections in the C# Language Specification:
1.6.6.5 Operators
7.2 Operators