**更新：**根据会话，需要根据匹配的卡类型和金额（可以是多条记录）从列表中更新db中的slno。至少这是我的理解。在这种情况下，你可以通过linq来做，因为我使用了linqpad，它是一种不同的方法来保存记录到db。因此您可能需要调整SubmitChanges（）;来替换你如何更新记录的方式（EF或SP或ADO调用）。等）来源：cheqlist

db table

void Main()
{
    var chklist = new List<Cheque>() {
        new Cheque(){Trantype = "Card", Debit = 50.00M, SlNo = 111},
        new Cheque(){Trantype = "Card", Debit = 20.00M, SlNo = 222},
        new Cheque(){Trantype = "tt", Debit = 55.00M, SlNo = 333}
    };

    //find match
    var res = from t1 in chklist
            from t2 in DtVoucherEntry.Where(x => t1.Trantype == x.TranType && t1.Debit == x.Amount).DefaultIfEmpty()
            where t2 != null
            select new { t1.SlNo, t2 };

    //set db value for slno
    res.ToList().ForEach(fe => {
        DtVoucherEntry.Where(w=> w.TranType == fe.t2.TranType).ToList().ForEach(ffe=> ffe.SlNo = fe.SlNo);
        SubmitChanges();//use your way to submit change of DtVoucherEntry to db
    });

DtVoucherEntry.Dump();
    
}

public class Cheque
{
    public string Trantype { get; set; }
    public int SlNo { get; set; }
    public decimal? Debit { get; set; }

    public Cheque() { }
}

结果，用来自列表

的值更新了db slno

*！！我试着创建一个例子为您提供一些数据。请调整问题。另外，请确认类属性/列数据类型。并澄清您的问题，根据所提供的数据，您希望得到什么。

CREATE TABLE [dbo].[dtVoucherEntry](
    [id] INT IDENTITY(1,1) NOT NULL ,
    [TranType] [VARCHAR](20) NULL,
    [SlNo] [INT] NULL,
    [Amount] [DECIMAL](16, 2) NULL
PRIMARY KEY CLUSTERED 
(
    [id] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
) ON [PRIMARY]
GO

insert into DtVoucherEntry (trantype, slno, amount)
values
('Card', 0, 50),
('Card', 0, 55),
('tt', 0, 55)

和代码

void Main()
{
    var chklist = new List<Cheque>() {
        new Cheque(){Trantype = "Card", Debit = 50},
        new Cheque(){Trantype = "Card", Debit = 20},
        new Cheque(){Trantype = "tt", Debit = 50}
    };
    
        
    foreach (Cheque details in chklist)
    {
        decimal? trantypeValue = DtVoucherEntry.AsEnumerable()
                .Where(entry => entry.TranType == details.Trantype && entry.Debit == details.Amount)
                .Select(tran => tran.SlNo)
                .FirstOrDefault();
        if (trantypeValue.HasValue)
        {
            details.SlNo = trantypeValue.Value;
        }
    }
}

public class Cheque
{
    public string Trantype {get;set;}
    public decimal? SlNo {get;set;}
    public decimal? Amount {get;set;}
    
    public Cheque(){}
}

更新：请确认初始数据：- 如果不正确-请评论我需要调整的内容和位置DB x1c4d 1x

支票清单：