比較兩個DataTables在C＃中的差異？

Question

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

我需要比較在C＃中兩個DataTable找到的差異。這兩個數據表具有相同的模式。什麼是最好的方式來做到這一點？可以使用linq查詢完成嗎？如果是，如何？

Answer 1

您可以使用LINQ加入兩個DataTable對象，匹配每一列。然後取IQueryable並查找前兩個DataTable對象中不在IQueryable中的所有行。

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. 
} 

上面的代碼應該工作，雖然我沒有測試它。

你也可以看看LINQ query on a DataTable，它有關於使用LINQ和DataTables的一些有用的信息。
寫作LINQ時，我也發現LINQ samples有幫助。