The value of a static readonly field is computed at runtime while the value of a const field is calculated at compile
time, which improves performance.
This rule raises an issue when a static readonly field is initialized with a value that is computable at compile time.
As specified by Microsoft, the list of types that can have a constant value are:
| C# type |
.Net Fwk type |
bool |
System.Boolean |
byte |
System.Byte |
sbyte |
System.SByte |
char |
System.Char |
decimal |
System.Decimal |
double |
System.Double |
float |
System.Single |
int |
System.Int32 |
uint |
System.UInt32 |
long |
System.Int64 |
ulong |
System.UInt64 |
short |
System.Int16 |
ushort |
System.UInt16 |
string |
System.String |
Noncompliant code example
namespace myLib
{
public class Foo
{
static readonly int x = 1; // Noncompliant
static readonly int y = x + 4; // Noncompliant
static readonly string s = "Bar"; // Noncompliant
}
}
Compliant solution
namespace myLib
{
public class Foo
{
const int x = 1;
const int y = x + 4;
const string s = "Bar";
}
}
