比较两个数据表在 C# 中的差异？ [复制]

Question

可能重复：
C#, how to compare two datatables A + B, how to show rows which are in B but not in A

我需要比较 c# 中的两个数据表以找出差异。这两个数据表具有相同的架构。最好的方法是什么？可以使用 linq 查询来完成吗？如果是，如何？

Answer 1

您可以使用 LINQ 连接两个 DataTable 对象，匹配每一列。然后取IQueryable 并找出前两个DataTable 对象中所有不在IQueryable 中的行。

示例：

private void SampleSolution(DataTable dt1, DataTable dt2)
{
    //If you have primary keys:
    var results = from table1 in dt1.AsEnumerable()
                    join table2 in dt2.AsEnumerable() on table1.Field<int>("id") equals table2.Field<int>("id")
                    where table1.Field<int>("ColumnA") != table2.Field<int>("ColumnA") || table1.Field<int>("ColumnB") != table2.Field<int>("ColumnB") || table1.Field<String>("ColumnC") != table2.Field<String>("ColumnC")
                    select table1;
    //This will give you the rows in dt1 which do not match the rows in dt2.  You will need to expand the where clause to include all your columns.


    //If you do not have primarry keys then you will need to match up each column and then find the missing.
    var matched = from table1 in dt1.AsEnumerable()
                    join table2 in dt2.AsEnumerable() on table1.Field<int>("ColumnA") equals table2.Field<int>("ColumnA")
                    where table1.Field<int>("ColumnB") == table2.Field<int>("ColumnB") || table1.Field<string>("ColumnC") == table2.Field<string>("ColumnC") || table1.Field<object>("ColumnD") == table2.Field<object>("ColumnD")
                    select table1;
    var missing = from table1 in dt1.AsEnumerable()
                    where !matched.Contains(table1)
                    select table1;
    //This should give you the rows which do not have a match.  You will need to expand the where clause to include all your columns.
}

上面的代码应该可以工作，虽然我没有测试过。

您还可以查看LINQ query on a DataTable，其中包含一些关于将 LINQ 与 DataTables 结合使用的有用信息。
我还发现LINQ samples 在编写 LINQ 时很有帮助。