using a for loop to iterate through a dictionary

I generally use a foreach loop to iterate through Dictionary.

Dictionary<string, string> dictSummary = new Dictionary<string, string>();

In this case I want to trim the entries of white space and the foreach loop does however not allow for this.

foreach (var kvp in dictSummary)
{
    kvp.Value = kvp.Value.Trim();    
}

How can I do this with a for loop?

for (int i = dictSummary.Count - 1; i >= 0; i--)
{
}

---

KeyValuePair<TKey, TValue> doesn't allow you to set the Value , it is immutable.

You will have to do it like this:

foreach(var kvp in dictSummary.ToArray())
    dictSummary[kvp.Key] = kvp.Value.Trim();

The important part here is the ToArray . That will copy the Dictionary into an array, so changing the dictionary inside the foreach will not throw an InvalidOperationException .

An alternative approach would use LINQ's ToDictionary method:

dictSummary = dictSummary.ToDictionary(x => x.Key, x => x.Value.Trim());

---

那这个呢？

for (int i = dictSummary.Count - 1; i >= 0; i--) {
  var item = dictSummary.ElementAt(i);
  var itemKey = item.Key;
  var itemValue = item.Value;
}

---

You don't need to use .ToArray() or .ElementAt() . It is as simple as accessing the dictionary with the key:

dictSummary.Keys.ToList().ForEach(k => dictSummary[k] = dictSummary[k].Trim());

链接地址: http://www.djcxy.com/p/30390.html

上一篇: 在C＃中迭代字典

下一篇: 使用for循环遍历字典