Allows specification of pre-conditions, post-conditions, and object invariants. Contracts act as checked documentation of your external and internal APIs.
Assembly Reference: Microsoft.Contracts.Library
Namespace: System.Diagnostics.Contracts
Turning on Runtime Checking
Project Propertes | Code Contracts | Perform Runtime Contract Checking
Precondition becomes Debug.Assert()
Project Propertes | Code Contracts | Perform Static Contract Checking
Examples
// Requires - Pre-Condition// cr <tab> <tab>
Contract.Requires(denom > 0); // placed at the beginning of the method (pre-condition)
// Object Invariant
// Creating Object Invariant shortcut: cim <tab> <tab>
[ContractInvariantMethod]
protected void ObjectInvariant() {
Contract.Invariant(this.denom > 0);
// make this hold true all the time, not just where required is used
// Checked at end of every public method
}
// Ensure what is returned from a method
// Post-Condition
// ce <tab> <tab> for ensures
// cr <tab> <tab> for result
Contract.Ensures(Contract.Result<int>() >= 0); // added at the beginning of a method
Reference: http://msdn.microsoft.com/en-us/devlabs/dd491992.aspx
