Question

我在这里有一个不完整和破碎的例子，我想知道是否可以将一个函数传递给另一个将Model和属性考虑在内的函数？请参阅下面示例中的评论，我的意思是。

private void ValidateSurvey(Survey survey)
{
    // lines 1 to 10, or 1 to 8 or 11 to 16, etc
    for (var i = survey.FirstLine; i <= survey.LastLine; i++)
    {
        IsAnswerValid(survey, "1.1.1", i, /* some rules to apply here i.e. [TModel] != null && [TModel].Value == "foo" */ ) 
    }

}

private bool IsAnswerValid<TAnswer>(
    Survey survey,
    string rowName, 
    int lineNumber,
    Func<TAnswer, bool> answerValueValidator 
) where TAnswer : Answer
{
    if (survey == null)
        throw new ArgumentNullException("survey");
    if (answerValueValidator == null)
        throw new ArgumentNullException("answerValueValidator");
    if (string.IsNullOrWhiteSpace(rowName))
        throw new ArgumentNullException("Null/blank rowName specified");
    if(lineNumber < 0)
        throw new ArgumentOutOfRangeException("lineNumber must be positive");

    // get answer list for the required row
    var answerList = survey.Rows
        .Where(
            r => r.Name.Trim().ToLower() == rowName.Trim().ToLower() && r.Answers != null
        ).SelectMany(a => a.Answers);

    // get the first relevant answer for the line number specified
    var answer = answerList.FirstOrDefault(a => a.LineNumber == lineNumber);

    return answerValueValidator(answer);

    //return (answer != null && answer.Value);
}

更新：根据答案显示lambda使用和删除泛型，现在很抱歉让我自己因语法错误而导致智能感知无法出现，希望有人可能会发现这个有用

private void ValidateSurvey(Survey survey)
{
    // lines 1 to 10, or 1 to 8 or 11 to 16, etc
    for (var i = survey.FirstLine; i <= survey.LastLine; i++)
    {
        IsAnswerValid(survey, "1.1.1", i, a => a != null && a.Value = "foo" ) 
    }

}

private bool IsAnswerValid(
    Survey survey,
    string rowName, 
    int lineNumber,
    Func<Answer, bool> answerValueValidator 
)
{
    if (survey == null)
        throw new ArgumentNullException("survey");
    if (answerValueValidator == null)
        throw new ArgumentNullException("answerValueValidator");
    if (string.IsNullOrWhiteSpace(rowName))
        throw new ArgumentNullException("Null/blank rowName specified");
    if(lineNumber < 0)
        throw new ArgumentOutOfRangeException("lineNumber must be positive");

    // get answer list for the required row
    var answerList = survey.Rows
        .Where(
            r => r.Name.Trim().ToLower() == rowName.Trim().ToLower() && r.Answers != null
        ).SelectMany(a => a.Answers);

    // get the first relevant answer for the line number specified
    var answer = answerList.FirstOrDefault(a => a.LineNumber == lineNumber);

    return answerValueValidator(answer);
}

Answer 1

您正在寻找lambda表达式：

IsAnswerValid<Answer>(survey, "1.1.1", i, a => a.Something || a.SomethingElse);

Answer 2

我认为你已经接近你想要的 - 尝试改变这个：

// get the first relevant answer for the line number specified
var answer = answerList.FirstOrDefault(a => a.LineNumber == lineNumber);

对此：

// get the first relevant answer for the line number specified
var answer = answerList
    .OfType<TAnswer>()
    .FirstOrDefault(a => a.LineNumber == lineNumber);

然后您可以传入任何Answer -> bool lambda：

IsAnswerValid<Answer>(survey, "1.1.1", i, ans => ans.LineNumber == 1);

将函数传递给c＃中的另一个函数以调用给定模型

2 个答案: