c# - Lambda 表达式作为字典中的键

Question

所以很正常Dictionary<string, Action>我这样使用:

validationsDictionary["ThisValidation"]();

但是，字符串可能会被遗漏。所以我想使用模型的属性作为键:

validationsDictionary[x => x.ThisProperty]();

但是，我不知道确切的类型是什么，我试过这些:

Dictionary<Func<Model>, Action>
Dictionary<Expressions<Model>, Action>
Dictionary<Expression<Func<Model>>, Action>

我知道有些人不评价将函数用作键。所以我可以做这样的事情:

void Validate(Expression<Func<Model>> key) 
{
    validationsDictionary[key.ToString()]();
}

我不知道key.ToString()是一个正确的属性，但你明白了要点。

编辑

所以，我用了这个:

Expression<Func<DisplayContentViewModel, object>> predicate

它就像一种享受，让我能够做到:x => x.SomeProperty

我想我可以使用 predicate.Name给出名称的字符串表示。所以现在我要弄清楚的是如何填充字典!

Answer 1

所以在查看@SriramSakthivel 关于如何从 lambda 获取属性名称的评论之后，我将它与我的代码结合起来，目前我得到了一个可行的解决方案:

private void Validate(Expression<Func<DisplayContentViewModel, object>> propertyLambda)
{
    var key = this.GetValidationKey(propertyLambda);

    this.validationsDictionary[key]();
}

private void CreateValidationRule(
    Expression<Func<DisplayContentViewModel, object>> propertyLambda,
    Action validationAction)
{
    if (this.validationsDictionary == null)
    {
        this.validationsDictionary = new Dictionary<string, Action>();
    }

    var key = this.GetValidationKey(propertyLambda);

    if (this.validationsDictionary.ContainsKey(key))
    {
        return;
    }

    this.validationsDictionary.Add(key, validationAction);
}

private string GetValidationKey(Expression<Func<DisplayContentViewModel, object>> propertyLambda)
{
    var member = propertyLambda.Body as UnaryExpression;

    if (member == null)
    {
        throw new ArgumentException(
            string.Format("Expression '{0}' can't be cast to a UnaryExpression.", propertyLambda));
    }

    var operand = member.Operand as MemberExpression;

    if (operand == null)
    {
        throw new ArgumentException(
            string.Format("Expression '{0}' can't be cast to an Operand.", propertyLambda));
    }

    return operand.Member.Name;
}