在DataTable上使用LINQ进行内部联接

Question

我有这2个DataTables，customerTableDT和customerAliasesTableDT。他们都是从数据库中填充的是这样的：

customerTableDT = UtilityDataAndFunctions.PerformDBReadTransactionDataTableFormat(String.Format("SELECT * FROM {0}", TableNames.customers)); 

customerAliasesTableDT = UtilityDataAndFunctions.PerformDBReadTransactionDataTableFormat(String.Format("SELECT * FROM {0}", TableNames.customerAliases)); 

现在，我试图做一个内部连接在两个DataTable这样的：

var customerNames = from customers in customerTableDT.AsEnumerable() 
        join aliases in customerAliasesTableDT.AsEnumerable on customers.Field<int>("CustomerID") equals aliases.Field<int>("CustomerID") 
        where aliases.Field<string>("Alias").Contains(iString) select customers.Field<string>("Name") 

但它给我这个错误：

The type of one of the expressions in the join clause is incorrect. Type inference failed in the call to 'Join'. 

如果我不得不在SQL写什么，我试图做的，它很简单：

SELECT * FROM CUSTOMERS C 
INNER JOIN CustomerAliases ALIASES ON ALIASES.CustomerID = C.CustomerID 
WHERE CA.Alias LIKE %STRING_HERE% 

任何帮助？

Answer 1

您AsEnumerable后错过了括号，所以它视为方法组，不IEnumerable<DataRow>：

var customerNames = from customers in customerTableDT.AsEnumerable() 
        join aliases in customerAliasesTableDT.AsEnumerable() on customers.Field<int>("CustomerID") equals aliases.Field<int>("CustomerID") 
        where aliases.Field<string>("Alias").Contains(iString) select customers.Field<string>("Name")