Question

我收到此错误：

无法投射类型的对象 'd__37'4 [System.Xml.Linq.XElement，BankOfBIT.Models.BankAccount，System.Int64，＆LT;＆GT; f__AnonymousType2'1 [System.Xml.Linq.XElement]]' 输入 'System.Collections.Generic.IEnumerable`1 [System.Xml.Linq.XElement]'。

我正在尝试执行这个lambda查询：

IEnumerable<XElement> transactionsWithMatchingAccountNumber
= (IEnumerable<XElement>) transactionswithValidAmount.Join(
    db.BankAccounts,
    transactions => long.Parse(transactions.Element("account_no").Value),
    accounts => accounts.AccountNumber,
    (transactions, accounts) => new { XElement = transactions });

我试图只获取与数据库中的帐号匹配的所有xml事务，以验证它们是否存在。

我有IEnumerable<XElement>，其中包含以下内容：

<transaction>
    <institution>34439</institution>
    <account_no>10000</account_no>
    <type>2</type>
    <amount>50</amount>
    <notes>withdrawal</notes>
</transaction>

我有2个EntityFramework MVC类与这些架构：

public class Transaction
{   
   [DatabaseGeneratedAttribute(DatabaseGeneratedOption.Identity)]
   public int TransactionId { get; set; }

   public long TransactionNumber { get; set; }

   [ForeignKey("BankAccount")]
   [Required]
   public int BankAccountId { get; set; }

   [ForeignKey("TransactionType")]
   [Required]
   public int TransactionTypeId { get; set; }

   public double Deposit { get; set; }

   public double Withdrawal { get; set; }

   [Required]
   public DateTime DateCreated { get; set; }

   public string Notes { get; set; }
   /// <summary>
   /// create account with default next num
   /// </summary>
   public void SetNextTransactionNumber()
   {
       this.TransactionNumber = (long) StoredProcedures.NextNumber("NextTransactionNumbers");
   }

   public virtual BankAccount BankAccount { get; set; }

   public virtual TransactionType TransactionType { get; set; }
}

public abstract class BankAccount
{
    [DatabaseGeneratedAttribute(DatabaseGeneratedOption.Identity)]
    public int BankAccountId { get; set; }

    [Display(Name="Account\nNumber")]
    public long AccountNumber { get; set; }

    [Required]
    [ForeignKey("Client")]
    public int ClientId { get; set; }

    [Required]
    [ForeignKey("AccountState")]
    public int AccountStateId { get; set; }

    [Required]
    [Display(Name = "Current\nBalance")]
    [DisplayFormat(DataFormatString="{0:c2}")]
    public double Balance { get; set; }

    [Required]
    [Display(Name = "Opening\nBalance")]
    [DisplayFormat(DataFormatString = "{0:c2}")]
    public double OpeningBalance { get; set; }

    [Required]
    [Display(Name = "Date\nCreated")]
    [DisplayFormat(DataFormatString = "{0:d}")]
    public DateTime DateCreated { get; set; }


    [Display(Name = "Account\nNotes")]
    public string Notes { get; set; }

    /// <summary>
    /// Returns the name of the account type
    /// </summary>
    [Display(Name = "Account\nType")]
    public string Description
    {
        get
        {
            return GetType().Name.Split('_')[0].Replace("Account","");
        }
    }

    /// <summary>
    /// Stores the bank account state
    /// </summary>
    public virtual AccountState AccountState { get; set; }

    /// <summary>
    /// Stores the client associated with the bank account
    /// </summary>
    public virtual Client Client { get; set; }

    /// <summary>
    /// Increments the account number static counter
    /// </summary>
    public abstract void SetNextAccountNumber();

    /// <summary>
    /// Changes the state of the bank account
    /// </summary>
    public void ChangeState()
    {
        BankOfBITContext db = new BankOfBITContext();

        AccountState lastState;
        AccountState futureState;

        do{

            lastState = db.AccountStates.Find(AccountStateId);

            lastState.StateChangeCheck(this);

            futureState = db.AccountStates.Find(AccountStateId);

        }while(lastState != futureState);
    }
}

Answer 1

尝试以下内容：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Xml;
using System.Xml.Linq;

namespace ConsoleApplication28
{
    class Program
    {
        static void Main(string[] args)
        {
            string xml =
                "<Root>" +
                    "<transaction>" +
                        "<institution>34439</institution>" +
                        "<account_no>10000</account_no>" +
                        "<type>2</type>" +
                        "<amount>50</amount>" +
                        "<notes>withdrawal</notes>" +
                    "</transaction>" +
                    "<transaction>" +
                        "<institution>34440</institution>" +
                        "<account_no>10001</account_no>" +
                        "<type>2</type>" +
                        "<amount>50</amount>" +
                        "<notes>withdrawal</notes>" +
                    "</transaction>" +
                "</Root>";

            XDocument doc = XDocument.Parse(xml);

            List<XElement> tranactions = doc.Descendants("transaction").ToList();

            var results = tranactions.Where(x => (int)x.Element("account_no") == 10000).Any(); 


        }
    }
}

无法转换JoinIterator类型的对象

1 个答案: