[英]Convert Array List to Comma Separated String in C#
I'm using String.Join to attempt to turn an array list into a string that is comma separated, such as 我正在使用String.Join尝试将数组列表转换为以逗号分隔的字符串,例如
xxx@xxx.com,yyy@xxx.com,zzz@xxx.com,www@xxx.com
I can't seem to get the syntax working. 我似乎无法使语法正常工作。
Here's what I'm trying: 这是我正在尝试的:
for (i = 0; i < xxx; i++)
{
MailingList = arrayList[i].ToString();
MailingList = string.Join(", ", MailingList.ToString());
Response.Write(MailingList.ToString());
}
Can you help me? 你能帮助我吗?
Thank you in advance- 先感谢您-
Guessing from the name of your variable ( arrayList
), you've got List<string[]>
or an equivalent type there. 从变量名(
arrayList
)猜测,您已经有了List<string[]>
或等效类型。
The issue here is that you're calling ToString()
on the array. 这里的问题是您要在数组上调用
ToString()
。 Try this instead: 尝试以下方法:
for (i = 0; i < xxx; i++)
{
var array = arrayList[i];
MailingList = string.Join(", ", array);
Response.Write(MailingList);
}
EDIT: If arrayList
is simply an ArrayList
containing strings, you can just do 编辑:如果
arrayList
只是包含字符串的ArrayList
,则可以执行
Response.Write(string.Join(", ", arrayList.OfType<string>()));
Personally I would avoid using nongeneric collections (such as ArrayList
) if possible and use strongly-typed collections from System.Collections.Generic
such as List<string>
. 就个人而言,我将尽可能避免使用非通用集合(例如
ArrayList
),而应使用System.Collections.Generic
强类型集合(例如List<string>
。 For example, if you have a piece of code that depends on that all contents of the ArrayList
are strings, it will suffer catastrophically if you accidentally add an item that's not a string. 例如,如果您有一段代码依赖于
ArrayList
所有内容都是字符串,那么如果您不小心添加了不是字符串的项目,它将遭受灾难性的影响。
EDIT 2: If your ArrayList
actually contains System.Web.UI.WebControls.ListItem
s like you mentioned in your comment: arrayList.AddRange(ListBox.Items);
编辑2:如果您的
ArrayList
实际上包含System.Web.UI.WebControls.ListItem
就像您在注释中提到的那样: arrayList.AddRange(ListBox.Items);
, then you'll need to use this instead: ,那么您将需要使用它:
Response.Write(string.Join(", ", arrayList.OfType<ListItem>()));
The second parameter for String.Join
needs to be an IEnumerable
. String.Join
的第二个参数必须是IEnumerable
。 Replace MailingList.ToString()
with arrayList
and it should work. 更换
MailingList.ToString()
与arrayList
,它应该工作。
Initialization: 初始化:
string result = string.Empty;
For value types: 对于值类型:
if (arrayList != null) {
foreach(var entry in arrayList){
result += entry + ',';
}
}
For reference types: 对于参考类型:
if (arrayList != null) {
foreach(var entry in arrayList){
if(entry != null)
result += entry + ',';
}
}
And cleanup: 并清理:
if(result == string.Empty)
result = null;
else
result = result.Substring(0, result.Length - 1);
most of the answers are already there, still posting a complete - working snippet 大多数答案已经存在,仍在发布完整的工作片段
string[] emailListOne = { "xxx@xxx.com", "yyy@xxx.com", "zzz@xxx.com", "www@xxx.com" };
string[] emailListTwo = { "xxx@xxx1.com", "yyy@xxx1.com", "zzz@xxx1.com", "www@xxx1.com" };
string[] emailListThree = { "xxx@xxx2.com", "yyy@xxx2.com", "zzz@xxx2.com", "www@xxx.com" };
string[] emailListFour = { "xxx@xxx3.com", "yyy@xxx3.com", "zzz@xxx3.com", "www@xxx3.com" };
List<string[]> emailArrayList = new List<string[]>();
emailArrayList.Add(emailListOne);
emailArrayList.Add(emailListTwo);
emailArrayList.Add(emailListThree);
emailArrayList.Add(emailListFour);
StringBuilder csvList = new StringBuilder();
int i = 0;
foreach (var list in emailArrayList)
{
csvList.Append(string.Join(",", list));
if(i < emailArrayList.Count - 1)
csvList.Append(",");
i++;
}
Response.Write(csvList.ToString());
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