在使用try ... catch隐式类型变量

问题描述

我喜欢使用隐式类型的几乎一切，因为它是干净和简单。然而，当我需要环绕单个语句try ... catch块，我必须打破了隐式类型，以确保变量有一个确定的值。这里有一个人为假设的例子：

I like using implicit typing for almost everything because it's clean and simple. However, when I need to wrap a try...catch block around a single statement, I have to break the implicit typing in order to ensure the variable has a defined value. Here's a contrived hypothetical example:

var s = "abc";

// I want to avoid explicit typing here
IQueryable<ABC> result = null;
try {
    result = GetData();
} catch (Exception ex) { }

if (result != null)
    return result.Single().MyProperty;
else
    return 0;

有没有一种方法，我可以叫的GetData（）与异常处理，而无需显式定义结果变量的类型？像的GetData（）。NullOnException（）？

Is there a way I can call GetData() with exception handling, but without having to explicitly define the type of the result variable? Something like GetData().NullOnException()?

推荐答案

这是一个常见的​​问题。我建议你​​只是坚持您现有的解决方案。

This is a common problem. I recommend that you just stick with your existing solution.

如果你真的想要一个选择，那就是：

If you really want an alternative, here it is:

static T NullOnException<T>(Func<T> producer) where T : class {
  try { return producer(); } catch { return null; } //please modify the catch!
}

//now call it
var result = NullOnException(() => GetData());

请修改此记录的例外或限制捕捞到一个具体类型。我并不赞同吞下所有的异常。

Please modify this to log the exception or restrict the catch to a concrete type. I do not endorse swallowing all exceptions.

由于这个答案正在读了很多我想指出的是，这个实现仅仅是演示质量。在生产code你应该将在评论中给出的建议。写自己一个强大的，精心设计的辅助功能，将竭诚为您服务好多年了。

As this answer is being read a lot I want to point out that this implementation is just of demo-quality. In production code you probably should incorporate the suggestions given in the comments. Write yourself a robust, well-designed helper function that will serve you well for years.

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