hi I'm rewriting a java code in C# and I'm stuck here:
public void printSolveInstructions() {
System.out.print(getSolveInstructionsString());
}
public String getSolveInstructionsString() {
if (isSolved()) {
return historyToString(solveInstructions);
} else {
return "No solve instructions - Puzzle is not possible to solve.";
}
}
public List<LogItem> getSolveInstructions() {
if (isSolved()) {
return Collections.unmodifiableList(solveInstructions);
} else {
return Collections.emptyList();
}
}
I know how to rewrite the first two methods (it's for referencing the last one) but I don't know the equivalent for Collections.unmodifiableList()
and Collections.emptyList()
solveInstructions
is of type List
here's the declaration in java and C#:
private ArrayList<LogItem> solveInstructions = new ArrayList<LogItem>() // java
private List<LogItem> solveInstructions = new List<LogItem>() // c#
update I rewrote the getSolveInstructions()
method in this way:
public List<LogItem> getSolveInstructions()
{
if (isSolved())
{
return solveInstructions.AsReadOnly();
}
else
{
return new List<LogItem>();
}
}
Now the problem is ide gives me an error when I use .AsReadOnly()
Your method returns either a List<LogItem>
, or an IReadOnlyCollection<LogItem>
(produced by call to List<T>.AsReadOnly()
method; however, your return type is List<LogItem>
, which is incompatible with the IReadOnlyCollection<LogItem>
. Change your method return type to IList<LogItem>
, which works for both types.
Note, since this method can return either a read-only or a read-write list, calling code should check the returned collection's IsReadOnly
property, before attempting to modify it.
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