動態LINQ查詢的數據表

Question

我有兩個數據表說cSVData和SQLDATA我想比較這兩個數據表的記錄是相同的或不那麼我使用這個查詢

 var matched = from table1 in cSVData.AsEnumerable() 
         join table2 in sqlData.AsEnumerable() on 
         table1.Field<string>("GlobalRank") equals table2.Field<string>("GlobalRank") 
         where 
         table1.Field<string>("GlobalRank") == table2.Field<string>("GlobalRank") 
         || table1.Field<string>("TldRank") == table2.Field<string>("TldRank") 
         || table1.Field<string>("Domain") == table2.Field<string>("Domain") 
         || table1.Field<string>("TLD") == table2.Field<string>("TLD") 
         || table1.Field<string>("RefSubNets") == table2.Field<string>("RefSubNets") 
         || table1.Field<string>("RefIPs") == table2.Field<string>("RefIPs") 
         || table1.Field<string>("IDN_Domain") == table2.Field<string>("IDN_Domain") 
         || table1.Field<string>("IDN_TLD") == table2.Field<string>("IDN_TLD") 
         || table1.Field<string>("PrevGlobalRank") == table2.Field<string>("PrevGlobalRank") 
         || table1.Field<string>("PrevTldRank") == table2.Field<string>("PrevTldRank") 
         || table1.Field<string>("PrevRefSubNets") == table2.Field<string>("PrevRefSubNets") 
         select table1; 

但這個表中的列名必須在where子句中應該採取所有列名

Answer 1

假設你cSVData和sqlData源DataTables，你應該能夠使用lambda語法通過列步驟動態方式：

var match = from table1 in cSVData.AsEnumerable() 
      join table2 in sqlData.AsEnumerable() on 
      table1.Field<string>("GlobalRank") equals table2.Field<string>("GlobalRank") 
      select new { table1, table2 }; 
foreach (var colname in cSVData.Columns.Cast<DataColumn>().Select(c => c.ColumnName)) 
    if (colname != "GlobalRank") 
     match = match.Where(both => both.table1.Field<string>(colname) == both.table2.Field<string>(colname)); 

match = match.Select(both => both.table1);