Warning: file_get_contents(/data/phpspider/zhask/data//catemap/2/csharp/325.json): failed to open stream: No such file or directory in /data/phpspider/zhask/libs/function.php on line 167

Warning: Invalid argument supplied for foreach() in /data/phpspider/zhask/libs/tag.function.php on line 1116

Notice: Undefined index: in /data/phpspider/zhask/libs/function.php on line 180

Warning: array_chunk() expects parameter 1 to be array, null given in /data/phpspider/zhask/libs/function.php on line 181
C# DataTable.Select()不同,然后添加值_C# - Fatal编程技术网

C# DataTable.Select()不同,然后添加值

C# DataTable.Select()不同,然后添加值,c#,C#,我只需要从columnA中选择不同的值,然后添加已连接到columnB的值 样本: columnA | columnB A 3 B 4 A 3 A 2 B 1 C 3 结果: columnA | columnB A 8 B

我只需要从columnA中选择不同的值,然后添加已连接到columnB的值

样本:

columnA    |    columnB
A                3
B                4
A                3
A                2 
B                1
C                3
结果:

columnA        |    columnB
A                    8
B                    5
C                    3
我找到了,但它只有列名数组作为参数

是否有其他方法或使用DataTable.Select()的示例

提前感谢

您可以使用和:

var colAGroups=tbl.AsEnumerable()
.GroupBy(row=>row.Field(“ColumnA”))
.选择(grp=>new
{
Value=grp.Key,
Sum=grp.Sum(行=>row.Field(“ColumnB”))
});
foreach(colAGroup中的var colAGroup)
{
WriteLine(String.Format(“{0}{1}”,colAGroup.Value,colAGroup.Sum));
}
var colAGroups = tbl.AsEnumerable()
                .GroupBy(row => row.Field<String>("ColumnA"))
                .Select(grp => new
                {
                    Value = grp.Key,
                    Sum = grp.Sum(row => row.Field<int>("ColumnB"))
                });

foreach (var colAGroup in colAGroups)
{
    Console.WriteLine(String.Format("{0} {1}", colAGroup.Value, colAGroup.Sum));
}