ILOG CPLEX .NET Reference Manual

Cplex.SolveCallback.IsPrimalFeasible Method 

Returns true if a primal feasible solution is available for the current node.

public virtual bool IsPrimalFeasible();

Remarks

If false is returned the solution may still be primal feasible, but the algorithm did not determine the feasibility before it terminated.

See Also

Cplex.SolveCallback Class | ILOG.CPLEX Namespace