Abstracting Dynamic Linq to SQL, где

Question

ОБНОВЛЕНИЕ: Ответ Groo был отмечен как правильный, так как это была бы хорошая альтернатива. Я решил придерживаться утверждений select/switch, чтобы избежать проблем с использованием рефлексии. Насколько я могу судить, нет возможности делать то, что я хочу, не используя Dynamic LINQ (и отражение) или декомпилятор (чтобы вручную закодировать каждый оператор LINQ, который я уже делаю вручную). Примечание: чтобы это обновление DropDownList16 с помощью DropDownList20 было удалено (необходимы символы).

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Есть ли способ абстрагироваться от построения динамического запроса Linq to SQL?

Я пытаюсь построить запрос Linq to SQL с предложением dynamic where, основанным на пользовательских фильтрах. Пользователь должен иметь возможность фильтровать строки, целые числа и даты, используя расширенные параметры (равные, не равные, содержащие, начинающиеся с и т. Д.). Пользователь должен иметь возможность использовать эти фильтры с количеством или несколькими столбцами по желанию.

Мой текущий переключатель для одной колонки:

VB

Select Case type 
    Case StringFilterTypes.Any ''//Do nothing (same as else) 
    Case StringFilterTypes.Contains 
     query = From view In query Where view.Name.Contains(userValue) Select view 
    Case StringFilterTypes.Exactly 
     query = From view In query Where view.Name = userValue Select view 
    Case StringFilterTypes.StartsWith 
     query = From view In query Where view.Name.StartsWith(userValue) Select view 
    Case StringFilterTypes.EndsWith 
     query = From view In query Where view.Name.EndsWith(userValue) Select view 
    Case Else     ''//Do nothing (same as Any). 
End Select 

C#

switch (type) { 
    case StringFilterTypes.Any: //Do nothing (same as else) 
     break; 
    case StringFilterTypes.Contains: 
     query = from view in querywhere view.Name.Contains(userValue)view; 
     break; 
    case StringFilterTypes.Exactly: 
     query = from view in querywhere view.Name == userValueview; 
     break; 
    case StringFilterTypes.StartsWith: 
     query = from view in querywhere view.Name.StartsWith(userValue)view; 
     break; 
    case StringFilterTypes.EndsWith: 
     query = from view in querywhere view.Name.EndsWith(userValue)view; 
     break; 
    default:     //Do nothing (same as Any). 
     break; 
} 

мне нужно будет использовать этот выбор/выключатель со всеми строковых столбцов и подобный переключатель с все столбцы integer и datetime. В результате я хочу, чтобы эти атрибуты select/switch были включены в функцию, где переменные типа, view.Name и userValue. Я могу передать тип и userValue, поскольку они являются локальными переменными, но как я могу передать view.Name в функцию?

Я просмотрел расширения, но они, похоже, требуют, чтобы я проходил просмотр, знал колонку уже и не поддерживаю команды select/switch.
Я также рассмотрел adding the where statements as strings, но чувствую, что это устраняет только две причины для использования linq (запросы, связанные с компилятором, автоматическое экранирование ввода пользователя для предотвращения внедрения sql).
Expression Trees выглядят многообещающими, но я не уверен, как их использовать, и если они являются хорошей идеей, где производительность является проблемой.

Лучшим решением было бы что-то вроде:

VB

Public Function ApplyFilters(query As IQueryable(Of DBName.ViewName)) As IQueryable(Of DBName.ViewName) 
    ''//... 
    Filter_String (query, Type, View.Name, userValue) 
    ''//... 
End Function 
Public Function Filter_String (query As IQueryable(Of DBName.ViewName), type As StringFilterTypes, column as ???, userValue As String) As IQueryable(Of DBName.ViewName) 
    Select Case type 
     Case StringFilterTypes.Any ''//Do nothing (same as else) 
     Case StringFilterTypes.Contains 
      query = From view In query Where column.Contains(userValue) Select view 
     Case StringFilterTypes.Exactly 
      query = From view In query Where column = userValue Select view 
     Case StringFilterTypes.StartsWith 
      query = From view In query Where column.StartsWith(userValue) Select view 
     Case StringFilterTypes.EndsWith 
      query = From view In query Where column.EndsWith(userValue) Select view 
     Case Else     ''//Do nothing (same as Any). 
    End Select 

    Return query 
End Function 

C#

public IQueryable<DBName.ViewName> ApplyFilters(IQueryable<DBName.ViewName> query) 
{ 
    //... 
    Filter_String (query, Type, View.Name, userValue); 
    //... 
} 
public IQueryable<DBName.ViewName> Filter_String(IQueryable<DBName.ViewName> query, StringFilterTypes type, ??? column, string userValue) 
{ 
    switch (type) { 
     case StringFilterTypes.Any: //Do nothing (same as else) 
      break; 
     case StringFilterTypes.Contains: 
      query = from view in querywhere column.Contains(userValue)view; 
      break; 
     case StringFilterTypes.Exactly: 
      query = from view in querywhere column == userValueview; 
      break; 
     case StringFilterTypes.StartsWith: 
      query = from view in querywhere column.StartsWith(userValue)view; 
      break; 
     case StringFilterTypes.EndsWith: 
      query = from view in querywhere column.EndsWith(userValue)view; 
      break; 
     default: 
      break;     //Do nothing (same as Any). 
    } 

    return query; 
} 

Update 2012/02/27:
Для BlueRaja - Дэнни Pflughoeft Я предоставляя образец приложения. Очевидно, что соединение с данными должно быть предоставлено конечным пользователем (база данных MS SQL с именем «Test» с таблицей с именем «testTable» и столбцами с именем «Column #», где # - все числа 1-20).

Default.aspx

<%@ Page Language="vb" AutoEventWireup="false" CodeBehind="Default.aspx.vb" Inherits="WebApplication1.test._Default" %> 

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> 

<html xmlns="http://www.w3.org/1999/xhtml"> 
<head runat="server"> 
    <title></title> 
</head> 
<body> 
    <form id="form1" runat="server"> 
    <div> 
     <asp:DropDownList ID="DropDownList1" runat="server"> 
      <asp:ListItem Selected="True" Text ="Any"   Value="-1" /> 
      <asp:ListItem Selected="False" Text ="Contains"  Value="0" /> 
      <asp:ListItem Selected="False" Text ="Is exactly" Value="1" /> 
      <asp:ListItem Selected="False" Text ="Starts with" Value="2" /> 
      <asp:ListItem Selected="False" Text ="Ends with" Value="3" /> 
     </asp:DropDownList> 
     <asp:TextBox ID="TextBox1" runat="server"></asp:TextBox> 
     <br /> 

     <asp:DropDownList ID="DropDownList2" runat="server"> 
      <asp:ListItem Selected="True" Text ="Any"   Value="-1" /> 
      <asp:ListItem Selected="False" Text ="Contains"  Value="0" /> 
      <asp:ListItem Selected="False" Text ="Is exactly" Value="1" /> 
      <asp:ListItem Selected="False" Text ="Starts with" Value="2" /> 
      <asp:ListItem Selected="False" Text ="Ends with" Value="3" /> 
     </asp:DropDownList> 
     <asp:TextBox ID="TextBox2" runat="server"></asp:TextBox> 
     <br /> 

     <asp:DropDownList ID="DropDownList3" runat="server"> 
      <asp:ListItem Selected="True" Text ="Any"   Value="-1" /> 
      <asp:ListItem Selected="False" Text ="Contains"  Value="0" /> 
      <asp:ListItem Selected="False" Text ="Is exactly" Value="1" /> 
      <asp:ListItem Selected="False" Text ="Starts with" Value="2" /> 
      <asp:ListItem Selected="False" Text ="Ends with" Value="3" /> 
     </asp:DropDownList> 
     <asp:TextBox ID="TextBox3" runat="server"></asp:TextBox> 
     <br /> 

     <asp:DropDownList ID="DropDownList4" runat="server"> 
      <asp:ListItem Selected="True" Text ="Any"   Value="-1" /> 
      <asp:ListItem Selected="False" Text ="Contains" Value="0" /> 
      <asp:ListItem Selected="False" Text ="Is exactly" Value="1" /> 
      <asp:ListItem Selected="False" Text ="Starts with" Value="2" /> 
      <asp:ListItem Selected="False" Text ="Ends with" Value="3" /> 
     </asp:DropDownList> 
     <asp:TextBox ID="TextBox4" runat="server"></asp:TextBox> 
     <br /> 

     <asp:DropDownList ID="DropDownList5" runat="server"> 
      <asp:ListItem Selected="True" Text ="Any"   Value="-1" /> 
      <asp:ListItem Selected="False" Text ="Contains"  Value="0" /> 
      <asp:ListItem Selected="False" Text ="Is exactly" Value="1" /> 
      <asp:ListItem Selected="False" Text ="Starts with" Value="2" /> 
      <asp:ListItem Selected="False" Text ="Ends with" Value="3" /> 
     </asp:DropDownList> 
     <asp:TextBox ID="TextBox5" runat="server"></asp:TextBox> 
     <br /> 

     <asp:DropDownList ID="DropDownList6" runat="server"> 
      <asp:ListItem Selected="True" Text ="Any"   Value="-1" /> 
      <asp:ListItem Selected="False" Text ="Contains"  Value="0" /> 
      <asp:ListItem Selected="False" Text ="Is exactly" Value="1" /> 
      <asp:ListItem Selected="False" Text ="Starts with" Value="2" /> 
      <asp:ListItem Selected="False" Text ="Ends with" Value="3" /> 
     </asp:DropDownList> 
     <asp:TextBox ID="TextBox6" runat="server"></asp:TextBox> 
     <br /> 

     <asp:DropDownList ID="DropDownList7" runat="server"> 
      <asp:ListItem Selected="True" Text ="Any"   Value="-1" /> 
      <asp:ListItem Selected="False" Text ="Contains"  Value="0" /> 
      <asp:ListItem Selected="False" Text ="Is exactly" Value="1" /> 
      <asp:ListItem Selected="False" Text ="Starts with" Value="2" /> 
      <asp:ListItem Selected="False" Text ="Ends with" Value="3" /> 
     </asp:DropDownList> 
     <asp:TextBox ID="TextBox7" runat="server"></asp:TextBox> 
     <br /> 

     <asp:DropDownList ID="DropDownList8" runat="server"> 
      <asp:ListItem Selected="True" Text ="Any"   Value="-1" /> 
      <asp:ListItem Selected="False" Text ="Contains"  Value="0" /> 
      <asp:ListItem Selected="False" Text ="Is exactly" Value="1" /> 
      <asp:ListItem Selected="False" Text ="Starts with" Value="2" /> 
      <asp:ListItem Selected="False" Text ="Ends with" Value="3" /> 
     </asp:DropDownList> 
     <asp:TextBox ID="TextBox8" runat="server"></asp:TextBox> 
     <br /> 

     <asp:DropDownList ID="DropDownList9" runat="server"> 
      <asp:ListItem Selected="True" Text ="Any"   Value="-1" /> 
      <asp:ListItem Selected="False" Text ="Contains"  Value="0" /> 
      <asp:ListItem Selected="False" Text ="Is exactly" Value="1" /> 
      <asp:ListItem Selected="False" Text ="Starts with" Value="2" /> 
      <asp:ListItem Selected="False" Text ="Ends with" Value="3" /> 
     </asp:DropDownList> 
     <asp:TextBox ID="TextBox9" runat="server"></asp:TextBox> 
     <br /> 

     <asp:DropDownList ID="DropDownList10" runat="server"> 
      <asp:ListItem Selected="True" Text ="Any"   Value="-1" /> 
      <asp:ListItem Selected="False" Text ="Contains"  Value="0" /> 
      <asp:ListItem Selected="False" Text ="Is exactly" Value="1" /> 
      <asp:ListItem Selected="False" Text ="Starts with" Value="2" /> 
      <asp:ListItem Selected="False" Text ="Ends with" Value="3" /> 
     </asp:DropDownList> 
     <asp:TextBox ID="TextBox10" runat="server"></asp:TextBox> 
     <br /> 

     <asp:DropDownList ID="DropDownList11" runat="server"> 
      <asp:ListItem Selected="True" Text ="Any"   Value="-1" /> 
      <asp:ListItem Selected="False" Text ="Contains"  Value="0" /> 
      <asp:ListItem Selected="False" Text ="Is exactly" Value="1" /> 
      <asp:ListItem Selected="False" Text ="Starts with" Value="2" /> 
      <asp:ListItem Selected="False" Text ="Ends with" Value="3" /> 
     </asp:DropDownList> 
     <asp:TextBox ID="TextBox11" runat="server"></asp:TextBox> 
     <br /> 

     <asp:DropDownList ID="DropDownList12" runat="server"> 
      <asp:ListItem Selected="True" Text ="Any"   Value="-1" /> 
      <asp:ListItem Selected="False" Text ="Contains"  Value="0" /> 
      <asp:ListItem Selected="False" Text ="Is exactly" Value="1" /> 
      <asp:ListItem Selected="False" Text ="Starts with" Value="2" /> 
      <asp:ListItem Selected="False" Text ="Ends with" Value="3" /> 
     </asp:DropDownList> 
     <asp:TextBox ID="TextBox12" runat="server"></asp:TextBox> 
     <br /> 

     <asp:DropDownList ID="DropDownList13" runat="server"> 
      <asp:ListItem Selected="True" Text ="Any"   Value="-1" /> 
      <asp:ListItem Selected="False" Text ="Contains" Value="0" /> 
      <asp:ListItem Selected="False" Text ="Is exactly" Value="1" /> 
      <asp:ListItem Selected="False" Text ="Starts with" Value="2" /> 
      <asp:ListItem Selected="False" Text ="Ends with" Value="3" /> 
     </asp:DropDownList> 
     <asp:TextBox ID="TextBox13" runat="server"></asp:TextBox> 
     <br /> 

     <asp:DropDownList ID="DropDownList14" runat="server"> 
      <asp:ListItem Selected="True" Text ="Any"   Value="-1" /> 
      <asp:ListItem Selected="False" Text ="Contains"  Value="0" /> 
      <asp:ListItem Selected="False" Text ="Is exactly" Value="1" /> 
      <asp:ListItem Selected="False" Text ="Starts with" Value="2" /> 
      <asp:ListItem Selected="False" Text ="Ends with" Value="3" /> 
     </asp:DropDownList> 
     <asp:TextBox ID="TextBox14" runat="server"></asp:TextBox> 
     <br /> 

     <asp:DropDownList ID="DropDownList15" runat="server"> 
      <asp:ListItem Selected="True" Text ="Any"   Value="-1" /> 
      <asp:ListItem Selected="False" Text ="Contains" Value="0" /> 
      <asp:ListItem Selected="False" Text ="Is exactly" Value="1" /> 
      <asp:ListItem Selected="False" Text ="Starts with" Value="2" /> 
      <asp:ListItem Selected="False" Text ="Ends with" Value="3" /> 
     </asp:DropDownList> 
     <asp:TextBox ID="TextBox15" runat="server"></asp:TextBox> 
     <br /> 

     <asp:GridView ID="GridView1" runat="server"> 
     </asp:GridView> 

    </div> 
    </form> 
</body> 
</html> 

Default.aspx.В.Б

Public Class _Default 
    Inherits System.Web.UI.Page 

    Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load 

    End Sub 

    Protected Sub Page_LoadComplete(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.LoadComplete 
     Dim _db As TestDataContext = New TestDataContext(ConfigurationManager.ConnectionStrings("TestDataConn").ConnectionString) 

     Dim query As IQueryable(Of testTable) = _ 
     From view In _db.testTables 
     Select view 

     Select Case DropDownList1.SelectedValue 
      Case "-1" 
       ''//Do nothing (same as else) 
      Case "0" 
       query = From view In query Where view.Column1.Contains(TextBox1.Text) Select view 
      Case "1" 
       query = From view In query Where view.Column1 = TextBox1.Text Select view 
      Case "2" 
       query = From view In query Where view.Column1.StartsWith(TextBox1.Text) Select view 
      Case "3" 
       query = From view In query Where view.Column1.EndsWith(TextBox1.Text) Select view 
      Case Else 
       ''//Do nothing (same as Any). 
     End Select 

     Select Case DropDownList2.SelectedValue 
      Case "-1" 
       ''//Do nothing (same as else) 
      Case "0" 
       query = From view In query Where view.Column2.Contains(TextBox2.Text) Select view 
      Case "1" 
       query = From view In query Where view.Column2 = TextBox2.Text Select view 
      Case "2" 
       query = From view In query Where view.Column2.StartsWith(TextBox2.Text) Select view 
      Case "3" 
       query = From view In query Where view.Column2.EndsWith(TextBox2.Text) Select view 
      Case Else 
       ''//Do nothing (same as Any). 
     End Select 

     Select Case DropDownList3.SelectedValue 
      Case "-1" 
       ''//Do nothing (same as else) 
      Case "0" 
       query = From view In query Where view.Column3.Contains(TextBox3.Text) Select view 
      Case "1" 
       query = From view In query Where view.Column3 = TextBox3.Text Select view 
      Case "2" 
       query = From view In query Where view.Column3.StartsWith(TextBox3.Text) Select view 
      Case "3" 
       query = From view In query Where view.Column3.EndsWith(TextBox3.Text) Select view 
      Case Else 
       ''//Do nothing (same as Any). 
     End Select 

     Select Case DropDownList4.SelectedValue 
      Case "-1" 
       ''//Do nothing (same as else) 
      Case "0" 
       query = From view In query Where view.Column4.Contains(TextBox4.Text) Select view 
      Case "1" 
       query = From view In query Where view.Column4 = TextBox4.Text Select view 
      Case "2" 
       query = From view In query Where view.Column4.StartsWith(TextBox4.Text) Select view 
      Case "3" 
       query = From view In query Where view.Column4.EndsWith(TextBox4.Text) Select view 
      Case Else 
       ''//Do nothing (same as Any). 
     End Select 

     Select Case DropDownList5.SelectedValue 
      Case "-1" 
       ''//Do nothing (same as else) 
      Case "0" 
       query = From view In query Where view.Column5.Contains(TextBox5.Text) Select view 
      Case "1" 
       query = From view In query Where view.Column5 = TextBox5.Text Select view 
      Case "2" 
       query = From view In query Where view.Column5.StartsWith(TextBox5.Text) Select view 
      Case "3" 
       query = From view In query Where view.Column5.EndsWith(TextBox5.Text) Select view 
      Case Else 
       ''//Do nothing (same as Any). 
     End Select 

     Select Case DropDownList6.SelectedValue 
      Case "-1" 
       ''//Do nothing (same as else) 
      Case "0" 
       query = From view In query Where view.Column6.Contains(TextBox6.Text) Select view 
      Case "1" 
       query = From view In query Where view.Column6 = TextBox6.Text Select view 
      Case "2" 
       query = From view In query Where view.Column6.StartsWith(TextBox6.Text) Select view 
      Case "3" 
       query = From view In query Where view.Column6.EndsWith(TextBox6.Text) Select view 
      Case Else 
       ''//Do nothing (same as Any). 
     End Select 

     Select Case DropDownList7.SelectedValue 
      Case "-1" 
       ''//Do nothing (same as else) 
      Case "0" 
       query = From view In query Where view.Column7.Contains(TextBox7.Text) Select view 
      Case "1" 
       query = From view In query Where view.Column7 = TextBox7.Text Select view 
      Case "2" 
       query = From view In query Where view.Column7.StartsWith(TextBox7.Text) Select view 
      Case "3" 
       query = From view In query Where view.Column7.EndsWith(TextBox7.Text) Select view 
      Case Else 
       ''//Do nothing (same as Any). 
     End Select 

     Select Case DropDownList8.SelectedValue 
      Case "-1" 
       ''//Do nothing (same as else) 
      Case "0" 
       query = From view In query Where view.Column8.Contains(TextBox8.Text) Select view 
      Case "1" 
       query = From view In query Where view.Column8 = TextBox8.Text Select view 
      Case "2" 
       query = From view In query Where view.Column8.StartsWith(TextBox8.Text) Select view 
      Case "3" 
       query = From view In query Where view.Column8.EndsWith(TextBox8.Text) Select view 
      Case Else 
       ''//Do nothing (same as Any). 
     End Select 

     Select Case DropDownList9.SelectedValue 
      Case "-1" 
       ''//Do nothing (same as else) 
      Case "0" 
       query = From view In query Where view.Column9.Contains(TextBox9.Text) Select view 
      Case "1" 
       query = From view In query Where view.Column9 = TextBox9.Text Select view 
      Case "2" 
       query = From view In query Where view.Column9.StartsWith(TextBox9.Text) Select view 
      Case "3" 
       query = From view In query Where view.Column9.EndsWith(TextBox9.Text) Select view 
      Case Else 
       ''//Do nothing (same as Any). 
     End Select 

     Select Case DropDownList10.SelectedValue 
      Case "-1" 
       ''//Do nothing (same as else) 
      Case "0" 
       query = From view In query Where view.Column10.Contains(TextBox10.Text) Select view 
      Case "1Column10" 
       query = From view In query Where view.Column10 = TextBox10.Text Select view 
      Case "2" 
       query = From view In query Where view.Column10.StartsWith(TextBox10.Text) Select view 
      Case "3" 
       query = From view In query Where view.Column10.EndsWith(TextBox10.Text) Select view 
      Case Else 
       ''//Do nothing (same as Any). 
     End Select 

     Select Case DropDownList11.SelectedValue 
      Case "-1" 
       ''//Do nothing (same as else) 
      Case "0" 
       query = From view In query Where view.Column11.Contains(TextBox11.Text) Select view 
      Case "1" 
       query = From view In query Where view.Column11 = TextBox11.Text Select view 
      Case "2" 
       query = From view In query Where view.Column11.StartsWith(TextBox11.Text) Select view 
      Case "3" 
       query = From view In query Where view.Column11.EndsWith(TextBox11.Text) Select view 
      Case Else 
       ''//Do nothing (same as Any). 
     End Select 

     Select Case DropDownList12.SelectedValue 
      Case "-1" 
       ''//Do nothing (same as else) 
      Case "0" 
       query = From view In query Where view.Column12.Contains(TextBox12.Text) Select view 
      Case "1" 
       query = From view In query Where view.Column12 = TextBox12.Text Select view 
      Case "2" 
       query = From view In query Where view.Column12.StartsWith(TextBox12.Text) Select view 
      Case "3" 
       query = From view In query Where view.Column12.EndsWith(TextBox12.Text) Select view 
      Case Else 
       ''//Do nothing (same as Any). 
     End Select 

     Select Case DropDownList13.SelectedValue 
      Case "-1" 
       ''//Do nothing (same as else) 
      Case "0" 
       query = From view In query Where view.Column13.Contains(TextBox13.Text) Select view 
      Case "1" 
       query = From view In query Where view.Column13 = TextBox13.Text Select view 
      Case "2" 
       query = From view In query Where view.Column13.StartsWith(TextBox13.Text) Select view 
      Case "3" 
       query = From view In query Where view.Column13.EndsWith(TextBox13.Text) Select view 
      Case Else 
       ''//Do nothing (same as Any). 
     End Select 

     Select Case DropDownList14.SelectedValue 
      Case "-1" 
       ''//Do nothing (same as else) 
      Case "0" 
       query = From view In query Where view.Column14.Contains(TextBox14.Text) Select view 
      Case "1" 
       query = From view In query Where view.Column14 = TextBox14.Text Select view 
      Case "2" 
       query = From view In query Where view.Column14.StartsWith(TextBox14.Text) Select view 
      Case "3" 
       query = From view In query Where view.Column14.EndsWith(TextBox14.Text) Select view 
      Case Else 
       ''//Do nothing (same as Any). 
     End Select 

     Select Case DropDownList15.SelectedValue 
      Case "-1" 
       ''//Do nothing (same as else) 
      Case "0" 
       query = From view In query Where view.Column15.Contains(TextBox15.Text) Select view 
      Case "1" 
       query = From view In query Where view.Column15 = TextBox15.Text Select view 
      Case "2" 
       query = From view In query Where view.Column15.StartsWith(TextBox15.Text) Select view 
      Case "3" 
       query = From view In query Where view.Column15.EndsWith(TextBox15.Text) Select view 
      Case Else 
       ''//Do nothing (same as Any). 
     End Select 


     GridView1.DataSource = query 
     GridView1.DataBind() 
    End Sub 

End Class 

Answer 1

Обратите внимание, что Dynamic LINQ не склонен к инъекции SQL таким же образом, как запрос каскадного от поставки пользовательских строк. Прошедшая строка является токенизированной и анализируется для создания дерева выражений, которое будет переведено в запрос, и оно не поддерживает неограниченное количество операций.

Вы не можете удалить таблицу, например, с помощью запроса Dynamic LINQ.

Тем не менее, важно отметить, что вам необходимо использовать Dynamic LINQ с параметрами-заполнителями (или «именованными параметрами»). Это имеет такие же преимущества, как использование именованных параметров с DBComand.

---

Кроме того, вы можете проверить PredicateBuilder по Albahari.

Это позволяет преобразовать статическое выражение как это:

p => p.Price > 100 && 
    p.Price < 1000 && 
    (p.Description.Contains ("foo") || p.Description.Contains ("far")) 

В это:

var outer = PredicateBuilder.True<Product>(); 
outer = outer.And (p => p.Price > 100); 
outer = outer.And (p => p.Price < 1000); 
{ 
    var inner = PredicateBuilder.False<Product>(); 
    inner = inner.Or (p => p.Description.Contains ("foo")); 
    inner = inner.Or (p => p.Description.Contains ("far")); 
    outer = outer.And (inner); 
} 

Answer 2

Там нет необходимости писать пользовательский Filter_String метод - уже есть метод звонившие может вызывать фильтрацию запроса по содержимому строки: Where(). Я не знаю, почему вы настаиваете на том, что должно быть заявление switch. Нет необходимости в заявлении switch.

Например, вместо написания Filter_String(query, StringFilterTypes.StartsWith, column, value), ваши абоненты могут просто написать

query.Where(o => o.column.StartsWith(value)) 

Там нет необходимости для нового интерфейса, когда LINQ уже изначально поддерживает то, что вам нужно.

Аналогично, вместо Filter_String(query, StringFilterTypes.EndsWith, column, value), они могут написать

query.Where(o => o.column.EndsWith(value)) 

и вместо Filter_String(query, StringFilterTypes.Contains, column, value), они могут написать

query.Where(o => o.column.Contains(value)) 

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Я надеюсь, что это ясно, что я хотел сказать в комментарии выше.