创建未定义长度的c＃对象数组？

I would like to create an object array in C# of undefined length and then populate the array in a loop like so...

我想在C＃中创建一个未定义长度的对象数组，然后像这样在循环中填充数组...

    string[] splitWords = message.Split(new Char[] { ' ' });

    Word[] words = new Word[];
    int wordcount = 0;
    foreach (string word in splitWords)
    {
        if (word == "") continue;
        words[wordcount] = new Word(word);
        wordcount++;
    }

However, I get the error... "Array creation must have array size or array initializer"

但是，我得到错误......“数组创建必须有数组大小或数组初始化程序”

I'm doing a lot more logic in the foreach loop that I've left out for brevity.

我在foreach循环中做了很多逻辑，我为了简洁而遗漏了。

7 个解决方案

#1

What you want to do is create:

你想要做的是创造：

List<Word> words = new List<Word>();

and then:

接着：

words.Add(new Word(word));

And finally when the loop is done if you need an array:

最后，当你需要一个数组时完成循环：

words.ToArray();

#2

If you're using C# 3.5, you can just do the following.

如果您使用的是C＃3.5，则可以执行以下操作。

var words = message
  .Split(new char[]{' '}) 
  .Where(x => x != "")
  .Select(x => new Word(x))
  .ToArray();

#3

You can't create an array of undefined length. This is where you'd use a generic List.

您无法创建未定义长度的数组。这是您使用通用列表的地方。

List<Word> words = new List<Word>();

#4

A friendly note, you can pass option to split to ignore empty entries. Assuming no other logic to prune out entries you can preinitialize your array like so:

友情提示，您可以通过选项拆分以忽略空条目。假设没有其他逻辑来删除条目，您可以预先初始化您的数组，如下所示：

string[] splitWords = message.Split(new Char[] {' '},
  StringSplitOptions.RemoveEmptyEntries);
Word[] words = new Word[splitWords.Length];

#5

Actually you may use list to populate your words first and then convert it easily to array like this:

实际上你可以使用list首先填充你的单词，然后将它轻松转换为数组，如下所示：

string[] splitWords = message.Split(new Char[] { ' ' });

List<Word> words = new List<Word>();
int wordcount = 0;
foreach (string word in splitWords)
{
    if (word == "") continue;
    words.add(new Word(word));
    //wordcount++;
}

wordcount = words.count;
return words.ToArray();

#6

I'm wondering why can't we just use a string variable (say x), initialize it and retrieve comma separated data in it and later use string[] variable (say y[]) and initialize it equal to x.Split(',') without having to initialize a blank array like follows:

我想知道为什么我们不能只使用字符串变量（比如x），初始化它并在其中检索逗号分隔数据，然后使用string []变量（比如y []）并初始化它等于x.Split（ '，'）无需初始化空白数组，如下所示：

string x = string.Empty;
string msg = "hi,how,r,u,xyz";

void Page_Load(object sender, EventArgs e)
     x = msg;
     string[] y = msg.Split(',');

I think this should work as needed but I didn't try running this so I am not sure. If someone thinks that my solution is wrong, please correct me.

我认为这应该按照需要工作，但我没有尝试运行这个，所以我不确定。如果有人认为我的解决方案有误，请纠正我。

#7

-2

I solved it by using an ArrayList and then casting it to the object array after iterating...

我通过使用ArrayList解决了它，然后在迭代后将其转换为对象数组...

    string[] splitWords = message.Split(new Char[] {' '});
    ArrayList wordList = new ArrayList();
    int wordcount = 0;
    foreach (string word in splitWords)
{
        if (word == "") continue;
        Word newWord = new Word(word);
        wordList.Add(newWord);
        wordcount++;
}
    Word[] words = (Word[])wordList.ToArray(typeof(Word));

I've heard the whole "create question/answer just to document it for others" is acceptable. Plus I'd like to hear if there are better suggestions. Thanks.

我听说整个“创建问题/答案只是为其他人记录”是可以接受的。另外，我想听听是否有更好的建议。谢谢。

#1