比较两个数据表以了解 C# 中的差异? [英] Compare two DataTables for differences in C#?

问题描述

可能的重复:
C#，如何比较两个数据表 A + B，如何显示在 B 中但不在 A 中的行

我需要在 C# 中比较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?

I need to compare two datatables in c# to find the differences. The two datatables have the same schema. What is the best way to do it? Can it be done using linq queries? If yes, How?

推荐答案

您可以使用 LINQ 连接两个 DataTable 对象，匹配每一列.然后取 IQueryable 并找到前两个 DataTable 对象中不在 IQueryable 中的所有行.

You could use LINQ to join the two DataTable objects, matching every column. Then take the IQueryable and find all the rows in the first two DataTable objects which are not in the IQueryable.

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，虽然我没有测试它.

The code above should work, though I did not test it.

您还可以查看 数据表上的 LINQ 查询，其中有一些有用的信息将 LINQ 与数据表一起使用.
我还发现 LINQ 示例 在编写 LINQ 时很有帮助.

You could also check out LINQ query on a DataTable which has some useful information on using LINQ with DataTables.
I also find the LINQ samples to be helpful when writting LINQ.

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