C# 将数据行（仅单列）转换为字符串列表
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/10708036/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
Convert datarow(only single column) to a string list
提问by
Please look at what is wrong? I want to convert datarow to a string list.
请大家看看有什么问题？我想将数据行转换为字符串列表。
public List<string> GetEmailList()
{
// get DataTable dt from somewhere.
List<DataRow> drlist = dt.AsEnumerable().ToList();
List<string> sEmail = new List<string>();
foreach (object str in drlist)
{
sEmail.Add(str.ToString()); // exception
}
return sEmail; // Ultimately to get a string list.
}
Thanks for help.
感谢帮助。
采纳答案by ean5533
There's several problems here, but the biggest one is that you're trying to turn an entire rowinto a string, when really you should be trying to turn just a single cellinto a string. You need to reference the first column of that DataRow, which you can do with brackets (like an array).
这里有几个问题，但最大的问题是您试图将整行转换为字符串，而实际上您应该尝试将单个单元格转换为字符串。您需要引用 that 的第一列DataRow，您可以使用括号（如数组）来完成。
Try something like this instead:
试试这样的：
public List<string> GetEmailList()
{
// get DataTable dt from somewhere.
List<string> sEmail = new List<string>();
foreach (DataRow row in dt.Rows)
{
sEmail.Add(row[0].ToString());
}
return sEmail; // Ultimately to get a string list.
}
回答by Juan Ayala
The Linq way ...
林克方式...
private static void Main(string[] args)
{
var dt = getdt();
var output = dt
.Rows
.Cast<DataRow>()
.ToList();
// or a CSV line
var csv = dt
.Rows
.Cast<DataRow>()
.Aggregate(new StringBuilder(), (sb, dr) => sb.AppendFormat(",{0}", dr[0]))
.Remove(0, 1);
Console.WriteLine(csv);
Console.ReadLine();
}
private static DataTable getdt()
{
var dc = new DataColumn("column1");
var dt = new DataTable("table1");
dt.Columns.Add(dc);
Enumerable.Range(0, 10)
.AsParallel()
.Select(i => string.Format("row {0}", i))
.ToList()
.ForEach(s =>
{
var dr = dt.NewRow();
dr[dc] = s;
dt.Rows.Add(dr);
});
return dt;
}
回答by Necromancer
Here's a one liner I got from ReSharper on how to do this, not sure of the performance implications, just thought I'd share it.
这是我从 ReSharper 那里得到的关于如何做到这一点的一个班轮，不确定对性能的影响，只是想我会分享它。
List<string> companyProxies = Enumerable.Select(
vendors.Tables[0].AsEnumerable(), vendor => vendor["CompanyName"].ToString()).ToList();
回答by d.popov
Here is how it would be with all additional syntax noise stripped: one-liner.
这是剥离所有附加语法噪声后的情况：单行。
public List<string> GetEmailList()
{
return dt.AsEnumerable().Select(r => r[0].ToString()).ToList();
}
