Question

我有一个DataTable，它有3个列，如IsMonday，Istuesday和IsWednesday，两个都是字符串字段，有Y和NI这样的数据想要获取每一行并以字符串形式返回结果。我想得到的是，< / p>

    if a row is Y,N,Y then the output will be 1 3,two is blank since it is N
    if a row is N,N,Y then the output will be   3,one and two is blank since it is N

像这样，使用Linq case语句或任何其他方式的任何想法

Answer 1

考虑到您从数据库返回的行集合看起来与此List类似。

var entity = new List<Entity>()
 {
 new Entity(){ IsMonday = "Y", IsTuesday = "N", IsWednesday = "Y"},
 new Entity() { IsMonday = "N", IsTuesday = "N", IsWednesday = "Y"},
 new Entity() { IsMonday = "Y", IsTuesday = "Y", IsWednesday = "N"}
 };

要获得预期的结果，您可以使用类似这样的代码

 foreach (var e in entity)
 {
   var a = e.IsMonday.Equals("y", StringComparison.OrdinalIgnoreCase) ? "1" : " ";
   var b = e.IsTuesday.Equals("y", StringComparison.OrdinalIgnoreCase) ? "2" : " ";
   var c = e.IsWednesday.Equals("y", StringComparison.OrdinalIgnoreCase) ? "3" : " ";
   var s = String.Format("{0} {1} {2}", a, b, c);
 }

这里的变量＆＃39;包含结果字符串。

Answer 2

这会将所有行转换为List<string>：

var columnNames = new[]{"IsMonday","Istuesday","IsWednesday"};
var rows = dt.AsEnumerable()
             .Select(row=>string.Join("", 
                          dt.Columns.Cast<DataColumn>()
                            .Where(col=>columnNames.Contains(col.ColumnName))
                            .Select(col=>row.Field<string>(col) == "N" ? " " :
                                         (col.Ordinal+1).ToString()))).ToList();

请注意，您说"N"之类的内容将替换为空白，但看起来您的意思是空间，所以我使用了空格代替，你可以把它换成你想要的任何东西。

如果您只想将特定行转换为字符串，则它非常相似：

//the input is row
var rowString = string.Join("", 
                  dt.Columns.Cast<DataColumn>()
                            .Where(col=>columnNames.Contains(col.ColumnName))
                            .Select(col=>row.Field<string>(col) == "N" ? " " :
                                         (col.Ordinal+1).ToString())).ToList();

选择Linq中Datatable数据行中的大小写

2 个答案: