LINQ全文搜索

本文介绍了LINQ全文搜索的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述

您好，谢谢，

我正在尝试实现搜索功能，在该功能中可以将结果填充到Gridview中.我正在使用LINQ在C#中查询我的数据库.

I am trying to implement a search function where the results could be populated to a Gridview. I am using LINQ to query my db in c#.

我要解决的问题是，如果用户要使用多个搜索词搜索多个列/字段，那我该怎么办?因此，例如，如果我用这3个字段搜索一个表，并且有一些数据，例如:

The problem I am trying to figure out is, if the user want to search through multiple columns/fields with more than one search term, then how do I do that? So instance if I search a table with these 3 fields and I had some data like:

firstName | lastname | players#

迈克尔|约旦| 12

迈克尔|约旦| 24

迈克尔|约旦| 45

DeAndre |约旦| 6

Jerome |约旦| 44

乔丹|火花| 88

Michael | Jordan | 12

Michael | Jordan | 24

Michael | Jordan | 45

DeAndre| Jordan | 6

Jerome| Jordan | 44

Jordan| Sparks| 88

现在，如果我搜索约旦，我将得到一切:

Now if I search for Jordan I get everything:

如果我搜索迈克尔·乔丹，我将获得第1,2,3行.

If I search Michael Jordan than I should get row #s 1,2,3 back.

如果我搜索Jordan Jordan Sparks 88，则应该返回第6行.

If I search Jordan Sparks 88 than I should row # 6 back.

所以我的问题是我不知道搜索词在表中的什么位置，因此我必须搜索所有列/字段.在当前代码中，我需要遍历每个列/字段的名称，然后使用Contains()然后||. (或")，但仅适用于1个搜索字词.

So my problem is I don't know where in the table the search term may be so I must search all columns/fields. In my current code, I have something where I go through each column/field name and use the Contains() then || ("or"), but it only works for 1 search term.

是否有一种优雅，简便的方法来搜索和过滤整个linq表，以使列表最小化?从那里，我将结果添加到数据源，然后将其绑定.

Is there an elegant and easy way to search and filter through a whole linq table so that the list is minimized? From there I will add that result to a datasource and then bind it.

@Sphinxxx我正在使用典型的gridview.看起来像这样:

@Sphinxxx I am using a typical gridview. It looks like this:

<asp:GridView ID="GridView" runat="server" AllowSorting="True" PagerStyle-Mode="NumericPages" AutoGenerateColumns="false" Width="100%" CssClass="gridView" OnPageIndexChanging="GridView_PageIndexChanging" AllowPaging="True" DataKeyNames="idPlayersList" OnRowCommand="GridView_RowCommand" OnRowEditing="GridView_RowEditing" OnRowCancelingEdit="GridView_CancelEditRow" OnRowUpdating="GridView_UpdateRow" OnRowDataBound="GridView_RowDataBound"> <RowStyle CssClass="rowStyle"></RowStyle> <asp:BoundField DataField="FirstName" HeaderText="First Name" SortExpression="FirstName" /> <asp:BoundField DataField="LastName" HeaderText="Last Name" SortExpression="LastName" /> <asp:BoundField DataField="PlayersNumber" HeaderText="Players Number" SortExpression="PlayersNumber" /> <asp:TemplateField HeaderText="Team" SortExpression="Team"> <EditItemTemplate> <asp:DropDownList ID="ddlTeam" runat="server" CssClass="dropdown" AutoPostBack="True" AppendDataBoundItems="true" DataTextField="TeamName" DataValueField="idTeam"> </asp:DropDownList> </EditItemTemplate> <ItemTemplate> <asp:Label ID="lblTeam" runat="server" Text='<%# Bind("TeamName") %>'></asp:Label> </ItemTemplate> </asp:TemplateField>

我当前的搜索功能如下:

My current search function looks something like this:

/** * This method is for button search functionality * */ protected void btnSearch_Click(object sender, EventArgs e) { // Call to Entity Model Framework DBModel.DBEntities context = new DBModel.DBEntities(); string[] searchTerms = txtSearch.Text.Trim().Split('&'); //Prepare to build a "players" query: IQueryable<DBModel.playersList> playersListQuery = context.playersLists; foreach (var term in searchTerms) { //Refine our query, one search term at a time: playersListQuery = playersListQuery.Where(p => p.isDeleted == false && (p.FirstName.Contains(term.Trim()) || p.LastName.Contains(term.Trim()) || p.PlayersNumber.Contains(term.Trim()) || p.Team.Name.Contains(term.Trim()))); } //Now we have the complete query. Get the results from the database: var filteredplayersList = playersListQuery.Select(s => new { idPlayersList = s.idPlayersList, FirstName = s.FirstName, LastName = s.LastName, PlayersNumber = s.PlayersNumber, TeamName = s.Team.Name }).ToList(); GridView.DataSource = filteredplayersList; //Connecting query to the datasource Gridview GridView.DataBind(); //Binding Gridview }

推荐答案

幸运的是，在Linq2SQL中创建多个AND(每个搜索词一个)很容易-只需向查询中添加.Where(..:

Luckily, creating multiple ANDs (one for each search term) is easy in Linq2SQL - just keep adding .Where(.. to your query:

string[] searchTerms = "Jordan Sparks 88".Split(' '); using (var dc = new MyDataContext()) { //Using DataContext.Log is handy //if we want to look at Linq2SQL's generated SQL: dc.Log = new System.IO.StringWriter(); //Prepare to build a "players" query: IQueryable<Player> playersQuery = dc.Players; //Refine our query, one search term at a time: foreach (var term in searchTerms) { //Create (and use) a local variable of the search term //to avoid the "outer variable trap": //stackoverflow/questions/3416758 //stackoverflow/questions/295593 var currentTerm = term.Trim(); playersQuery = playersQuery.Where(p => (p.isDeleted == false) && (p.FirstName.Contains(currentTerm) || p.LastName.Contains(currentTerm) || p.PlayersNumber.Contains(currentTerm) || p.Team.Name.Contains(currentTerm)) ); } //Now we have the complete query. Get the results from the database: var filteredPlayers = playersQuery.Select(p => new { p.idPlayer, p.FirstName, p.LastName, p.PlayersNumber, TeamName = p.Team.Name }) .ToArray(); //See if the generated SQL looked like it was supposed to: var sql = dc.Log.ToString(); }