Question

我正在尝试将where子句添加到现有的LINQ DataBind，但我没有做任何工作。我要添加的where子句检查表refAuthSigner中是否列IsActive == 1.

这是我现有的查询：

// populates Authorized Signer dropdownlist
        using (dbPSREntities10 myEntities = new dbPSREntities10())
        {
            var allSigners = from refAuthSigner in myEntities.refAuthSigners <--- where clause somewhere around here??
                             select new
                             {
                                 refAuthSignerID = refAuthSigner.refAuthSignerID,
                                 refAuthSignerName = refAuthSigner.refAuthSignerFirst + " " + refAuthSigner.refAuthSignerLast
                             };
            ddlAuthSigners.DataSource = allSigners;
            ddlAuthSigners.DataValueField = "refAuthSignerID";
            ddlAuthSigners.DataTextField = "refAuthSignerName";
            ddlAuthSigners.DataBind();
        }

我想添加一个where子句，类似于：

 var allSigners = from refAuthSigner in myEntities.refAuthSigners 
     where refAuthSigner.IsActive == 1

这段代码不对，只是想知道如何将where子句合并到代码中。谢谢！

Answer 1

只需使用：

where refAuthSigner.IsActive

由于它是一个布尔值，因此无法将其与整数进行比较。它是true或false，而不是1或0。（有些语言将两者混为一谈，C＃不是其中之一。）

无需将IsActive与任何内容进行比较。 where需要一个布尔值，IsActive是一个布尔值。你已经拥有了你需要的东西。

Answer 2

你可以发表声明：

var allsigners = refAuthSigner.Where(x => x.refAuthSigner.IsActive)

Answer 3

试试这个：

var allSigners = from refAuthSigner in myEntities.refAuthSigners
                 where refAuthSigner.IsActive
                 select new
                 {
                     refAuthSignerID = refAuthSigner.refAuthSignerID,
                     refAuthSignerName = refAuthSigner.refAuthSignerFirst + " " + refAuthSigner.refAuthSignerLast
                 };

Answer 4

Operator of '==' cannot be applied to operands of type 'bool' and 'int'. IsActive is type bit in SqlServer

如果这是错误，您将尝试使用Any代替Where，因为它返回bool

Answer 5

// populates Authorized Signer dropdownlist
        using (dbPSREntities10 myEntities = new dbPSREntities10())
        {
            var allSigners = from refAuthSigner in myEntities.refAuthSigners
                             where refAuthSigner.IsActive
                             select new
                             {
                                 refAuthSignerID = refAuthSigner.refAuthSignerID,
                                 refAuthSignerName = refAuthSigner.refAuthSignerFirst + " " + refAuthSigner.refAuthSignerLast
                             };
            ddlAuthSigners.DataSource = allSigners;
            ddlAuthSigners.DataValueField = "refAuthSignerID";
            ddlAuthSigners.DataTextField = "refAuthSignerName";
            ddlAuthSigners.DataBind();
        }

LINQ to Entities DataBind中的where子句

5 个答案: