如何即时构建 WCF 查询？

发布于 2024-09-18 01:01:11 字数 875 浏览 7 评论 0原文

我想构建一些 linq，或者动态构建一个查询字符串并将其传递给 WCF 数据服务（使用实体框架数据模型）。

像这样的东西：

 public List<DocumentInformationRecord> SearchClientDocs(string clientCode,
            string clientName, string contactName, string groupCode, string groupName,
            string filename, string createdby, DateTime dateFrom, DateTime dateTo)
 {
   List<DocumentInformationRecord> results = new List<DocumentInformationRecord>();
   if(!string.IsNullOrEmpty(clientCode)) 
   //Add the client code clause...

等等..

var qry = from c in context.DocumentInformationRecord.where(dynamicQuery);

            //Etc......

有什么想法吗？我尝试了谓词构建器（http://www.albahari.com/nutshell/predicatebuilder.aspx< /a>) 但得到了一些无效操作异常......

原文

I'd like to build some linq or alternatively, build a query string on the fly and pass it to a WCF Data Service (with Entity Framework data model).

Something like this:

 public List<DocumentInformationRecord> SearchClientDocs(string clientCode,
            string clientName, string contactName, string groupCode, string groupName,
            string filename, string createdby, DateTime dateFrom, DateTime dateTo)
 {
   List<DocumentInformationRecord> results = new List<DocumentInformationRecord>();
   if(!string.IsNullOrEmpty(clientCode)) 
   //Add the client code clause...

etc..

var qry = from c in context.DocumentInformationRecord.where(dynamicQuery);

            //Etc......

Any ideas? I tried the predicate builder (http://www.albahari.com/nutshell/predicatebuilder.aspx) but got some invalid operation exceptions.....

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寻找我们的幸福 2024-09-25 01:01:11

我不确定我完全理解你的问题，但我有时会编写代码来根据输入的不同部分构建 LINQ 查询。通常情况是这样的：

var qry = from item in someList
          select item;

if (nameFilter != null)
{
    qry = qry.Where(item => item.Name == nameFilter);
}

if (someOtherFilter != null)
{
    qry = qry.Where(item => item.SomeOtherStuff == someOtherFilter);
}
// and so on

这样您就可以逐步构建查询。您可以这样做是因为延迟执行；在开始迭代结果之前，不会对数据源执行查询。

I am not sure I entirely understand your question, but I have sometimes written code to build up LINQ queries with different parts depending on input. Typically that goes something like this:

var qry = from item in someList
          select item;

if (nameFilter != null)
{
    qry = qry.Where(item => item.Name == nameFilter);
}

if (someOtherFilter != null)
{
    qry = qry.Where(item => item.SomeOtherStuff == someOtherFilter);
}
// and so on

That way you can build the query step by step. You can do this because of deferred execution; the query will not be executed against the data source until you start iterating over the result.

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