Evaluate

IComparisonExpressionEvaluator.Evaluate method

Valuta l’espressione di confronto.

public ComparisonEvaluationResult Evaluate(Field field, ComparisonExpression expression)

Osservazioni

L’implementazione dovrebbe restituirenull per indicare che deve essere eseguita la valutazione predefinita.

Esempi

Mostra come implementare la valutazione personalizzata per i campi SE e CONFRONTA.

public void ConditionEvaluationExtensionPoint(string fieldCode, sbyte comparisonResult, string comparisonError,
    string expectedResult)
{
    const string left = "\"left expression\"";
    const string @operator = "<>";
    const string right = "\"right expression\"";

    DocumentBuilder builder = new DocumentBuilder();

    // Codici di campo che utilizziamo in questo esempio:
    // 1. " SE {0} {1} {2} \"argomento vero\" \"argomento falso\" ".
    // 2. "CONFRONTA {0} {1} {2} ".
    Field field = builder.InsertField(string.Format(fieldCode, left, @operator, right), null);

    // Se "comparisonResult" non è definito, creiamo "ComparisonEvaluationResult" con stringa, anziché bool.
    ComparisonEvaluationResult result = comparisonResult != -1
        ? new ComparisonEvaluationResult(comparisonResult == 1)
        : comparisonError != null ? new ComparisonEvaluationResult(comparisonError) : null;

    ComparisonExpressionEvaluator evaluator = new ComparisonExpressionEvaluator(result);
    builder.Document.FieldOptions.ComparisonExpressionEvaluator = evaluator;

    builder.Document.UpdateFields();

    Assert.AreEqual(expectedResult, field.Result);
    evaluator.AssertInvocationsCount(1).AssertInvocationArguments(0, left, @operator, right);
}

/// <summary>
/// Valutazione delle espressioni di confronto per FieldIf e FieldCompare.
/// </summary>
private class ComparisonExpressionEvaluator : IComparisonExpressionEvaluator
{
    public ComparisonExpressionEvaluator(ComparisonEvaluationResult result)
    {
        mResult = result;
        if (mResult != null)
        {
            Console.WriteLine(mResult.ErrorMessage);
            Console.WriteLine(mResult.Result);
        }
    }

    public ComparisonEvaluationResult Evaluate(Field field, ComparisonExpression expression)
    {
        mInvocations.Add(new[]
        {
            expression.LeftExpression,
            expression.ComparisonOperator,
            expression.RightExpression
        });

        return mResult;
    }

    public ComparisonExpressionEvaluator AssertInvocationsCount(int expected)
    {
        Assert.AreEqual(expected, mInvocations.Count);
        return this;
    }

    public ComparisonExpressionEvaluator AssertInvocationArguments(
        int invocationIndex,
        string expectedLeftExpression,
        string expectedComparisonOperator,
        string expectedRightExpression)
    {
        string[] arguments = mInvocations[invocationIndex];

        Assert.AreEqual(expectedLeftExpression, arguments[0]);
        Assert.AreEqual(expectedComparisonOperator, arguments[1]);
        Assert.AreEqual(expectedRightExpression, arguments[2]);

        return this;
    }

    private readonly ComparisonEvaluationResult mResult;
    private readonly List<string[]> mInvocations = new List<string[]>();
}

Guarda anche