如何实现EntityDataSource Where IN 实体sql子句答案

【问题标题】：How to implement EntityDataSource Where IN entity sql clause如何实现EntityDataSource Where IN 实体sql子句
【发布时间】：2010-05-04 21:01:22
【问题描述】：

我想将多个值传递给EntityDataSource的参数，例如：

Where="it.ORDER_ID IN {@OrderIdList}"（这是 EntityDataSource 上的一个属性）

<WhereParameters>
    <asp:ControlParameter 
       Name="OrderIdList" Type="Int16" 
       ControlID="OrderFilterControl" PropertyName="OrderIdList" 
    />
</WhereParameters>

这不起作用，因为 ORDER_ID 是 int32 类型，我需要传入多个值，例如{1,2,3}等

我尝试的下一件事是在代码隐藏中设置Where 子句，这一切都有效，除了我无法让DropDownLists 上的数据绑定工作。我的意思是EntityDataSource更新事件中的绑定下拉列表没有返回任何值。

我理想的解决方案是在EntityDataSource 上使用WhereParameter，但我们不胜感激。谢谢，托尼。

使用 AdventureWorks db 的完整代码示例如下：

Public Class EntityDataSourceWhereInClause
Inherits System.Web.UI.Page

Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
    CustomersEntityDataSource.Where = WhereClause ''# reset after each postback as its lost otherwise
End Sub

Private Sub cmdFilterCustomers_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles cmdFilterCustomers.Click
    Dim CustomerIdList As New Generic.List(Of Int32)
    For Each item As ListItem In CustomerIdCheckBoxList.Items
        If item.Selected Then
            CustomerIdList.Add(item.Value)
        End If
    Next

    Dim CustomerCsvList As String = String.Join(", ", CustomerIdList.Select(Function(o) o.ToString()).ToArray())
    WhereClause = "it.CustomerID IN {" & CustomerCsvList & "}"

    CustomersEntityDataSource.Where = WhereClause
    FormView1.PageIndex = 0

End Sub

''#  save between postbacks the custom Where IN clause
Public Property WhereClause() As String
    Get
        Return ViewState("WhereClause")
    End Get
    Set(ByVal value As String)
        ViewState.Add("WhereClause", value)
    End Set
End Property

Private Sub CustomersEntityDataSource_Updating(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.EntityDataSourceChangingEventArgs) Handles CustomersEntityDataSource.Updating
    Dim c = CType(e.Entity, EntityFrameworkTest.Customer)
    If c.Title.Length = 0 Then
        Response.Write("Title is empty string, so will save like this!")
    End If
End Sub

End Class

<%@ Page Language="vb" AutoEventWireup="false" CodeBehind="EntityDataSourceWhereInClause.aspx.vb"
Inherits="EntityFrameworkTest.EntityDataSourceWhereInClause" %>


<!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">

<%''# filter control %>
<div>
    <asp:EntityDataSource ID="CustomerIdListEntityDataSource" runat="server" ConnectionString="name=AdventureWorksLT2008Entities"
        DefaultContainerName="AdventureWorksLT2008Entities" EnableFlattening="False"
        EntitySetName="Customers" Select="it.[CustomerID]" OrderBy="it.[CustomerID]">
    </asp:EntityDataSource>
    <asp:CheckBoxList ID="CustomerIdCheckBoxList" runat="server" DataSourceID="CustomerIdListEntityDataSource"
        DataTextField="CustomerID" DataValueField="CustomerID" RepeatDirection="Horizontal">
    </asp:CheckBoxList>
    <asp:Button ID="cmdFilterCustomers" runat="server" Text="Apply Filter" />
</div>

<%  
    ''# you get this error passing in CSV in the where clause
    ''# The element type 'Edm.Int32' and the CollectionType 'Transient.collection[Edm.String(Nullable=True,DefaultValue=,MaxLength=,Unicode=,FixedLength=)]' are not compatible. The IN expression only supports entity, primitive, and reference types.  Near WHERE predicate, line 6, column 15. 
    ''# so have coded it manually in code-behind Where="it.CustomerID IN {@OrderIdList}"
%>
<asp:EntityDataSource ID="CustomersEntityDataSource" runat="server" ConnectionString="name=AdventureWorksLT2008Entities"
    DefaultContainerName="AdventureWorksLT2008Entities" EnableFlattening="False"
    EnableUpdate="True" EntitySetName="Customers"
    AutoGenerateOrderByClause="false">
</asp:EntityDataSource>
<%''# updating works with DropDownLists until the Where clause is set in code %>
<asp:FormView ID="FormView1" runat="server" AllowPaging="True" CellPadding="4" DataKeyNames="CustomerID"
    DataSourceID="CustomersEntityDataSource" ForeColor="#333333">
    <EditItemTemplate>
        CustomerID:
        <asp:Label ID="CustomerIDLabel1" runat="server" Text='<%# Eval("CustomerID") %>' />
        <br />
        NameStyle:
        <asp:CheckBox ID="NameStyleCheckBox" runat="server" Checked='<%# Bind("NameStyle") %>' />
        <br />
        Title:
        <%''# the SelectedValue is not Bound to the EF object if the Where clause is updated in code-behind %>
        <asp:DropDownList ID="ddlTitleBound" runat="server" DataSourceID="TitleEntityDataSource"
            DataTextField="Title" DataValueField="Title" AutoPostBack="false" AppendDataBoundItems="true"
            SelectedValue='<%# Bind("Title") %>'>
        </asp:DropDownList>
        <asp:EntityDataSource ID="TitleEntityDataSource" runat="server" ConnectionString="name=AdventureWorksLT2008Entities"
            DefaultContainerName="AdventureWorksLT2008Entities" EnableFlattening="False"
            EntitySetName="Customers" Select="it.[Title]" GroupBy="it.[Title]" ViewStateMode="Enabled">
        </asp:EntityDataSource>
        <br />
        FirstName:
        <asp:TextBox ID="FirstNameTextBox" runat="server" Text='<%# Bind("FirstName") %>' />
        <br />
        MiddleName:
        <asp:TextBox ID="MiddleNameTextBox" runat="server" Text='<%# Bind("MiddleName") %>' />
        <br />
        LastName:
        <asp:TextBox ID="LastNameTextBox" runat="server" Text='<%# Bind("LastName") %>' />
        <br />
        Suffix:
        <asp:TextBox ID="SuffixTextBox" runat="server" Text='<%# Bind("Suffix") %>' />
        <br />
        CompanyName:
        <asp:TextBox ID="CompanyNameTextBox" runat="server" Text='<%# Bind("CompanyName") %>' />
        <br />
        SalesPerson:
        <asp:TextBox ID="SalesPersonTextBox" runat="server" Text='<%# Bind("SalesPerson") %>' />
        <br />
        EmailAddress:
        <asp:TextBox ID="EmailAddressTextBox" runat="server" Text='<%# Bind("EmailAddress") %>' />
        <br />
        Phone:
        <asp:TextBox ID="PhoneTextBox" runat="server" Text='<%# Bind("Phone") %>' />
        <br />
        PasswordHash:
        <asp:TextBox ID="PasswordHashTextBox" runat="server" Text='<%# Bind("PasswordHash") %>' />
        <br />
        PasswordSalt:
        <asp:TextBox ID="PasswordSaltTextBox" runat="server" Text='<%# Bind("PasswordSalt") %>' />
        <br />
        rowguid:
        <asp:TextBox ID="rowguidTextBox" runat="server" Text='<%# Bind("rowguid") %>' />
        <br />
        ModifiedDate:
        <asp:TextBox ID="ModifiedDateTextBox" runat="server" Text='<%# Bind("ModifiedDate") %>' />
        <br />
        <asp:LinkButton ID="UpdateButton" runat="server" CausesValidation="True" CommandName="Update"
            Text="Update" />
        &nbsp;<asp:LinkButton ID="UpdateCancelButton" runat="server" CausesValidation="False"
            CommandName="Cancel" Text="Cancel" />
    </EditItemTemplate>
    <EditRowStyle BackColor="#999999" />
    <FooterStyle BackColor="#5D7B9D" Font-Bold="True" ForeColor="White" />
    <HeaderStyle BackColor="#5D7B9D" Font-Bold="True" ForeColor="White" />
    <ItemTemplate>
        CustomerID:
        <asp:Label ID="CustomerIDLabel" runat="server" Text='<%# Eval("CustomerID") %>' />
        <br />
        NameStyle:
        <asp:CheckBox ID="NameStyleCheckBox" runat="server" Checked='<%# Bind("NameStyle") %>'
            Enabled="false" />
        <br />
        Title:
        <asp:Label ID="TitleLabel" runat="server" Text='<%# Bind("Title") %>' />
        <br />
        FirstName:
        <asp:Label ID="FirstNameLabel" runat="server" Text='<%# Bind("FirstName") %>' />
        <br />
        MiddleName:
        <asp:Label ID="MiddleNameLabel" runat="server" Text='<%# Bind("MiddleName") %>' />
        <br />
        LastName:
        <asp:Label ID="LastNameLabel" runat="server" Text='<%# Bind("LastName") %>' />
        <br />
        Suffix:
        <asp:Label ID="SuffixLabel" runat="server" Text='<%# Bind("Suffix") %>' />
        <br />
        CompanyName:
        <asp:Label ID="CompanyNameLabel" runat="server" Text='<%# Bind("CompanyName") %>' />
        <br />
        SalesPerson:
        <asp:Label ID="SalesPersonLabel" runat="server" Text='<%# Bind("SalesPerson") %>' />
        <br />
        EmailAddress:
        <asp:Label ID="EmailAddressLabel" runat="server" Text='<%# Bind("EmailAddress") %>' />
        <br />
        Phone:
        <asp:Label ID="PhoneLabel" runat="server" Text='<%# Bind("Phone") %>' />
        <br />
        PasswordHash:
        <asp:Label ID="PasswordHashLabel" runat="server" Text='<%# Bind("PasswordHash") %>' />
        <br />
        PasswordSalt:
        <asp:Label ID="PasswordSaltLabel" runat="server" Text='<%# Bind("PasswordSalt") %>' />
        <br />
        rowguid:
        <asp:Label ID="rowguidLabel" runat="server" Text='<%# Bind("rowguid") %>' />
        <br />
        ModifiedDate:
        <asp:Label ID="ModifiedDateLabel" runat="server" Text='<%# Bind("ModifiedDate") %>' />
        <br />
        <asp:LinkButton ID="EditButton" runat="server" CausesValidation="False" CommandName="Edit"
            Text="Edit" />
    </ItemTemplate>
    <PagerSettings Position="Top" />
    <PagerStyle BackColor="#284775" ForeColor="White" HorizontalAlign="Center" />
    <RowStyle BackColor="#F7F6F3" ForeColor="#333333" />
</asp:FormView>
</form>

【问题讨论】：

标签： entity-framework entitydatasource entity-sql

【解决方案1】：

在浪费了很多时间之后，我现在可以正常工作了！

与 FormView 分页相关的问题，通过在 Edit 上将 AllowPaging 设置为 False 一切正常。

仅当您在 HTML 中的 FormView 上有以下内容时才会发生这种情况：

<PagerSettings Mode="NextPrevious" Position="Top" />

使用默认分页，您看不到问题。

【讨论】：

【解决方案2】：

如果分页被禁用并且您仍然遇到问题，请使用以下替代解决方法：

Private Sub DetailsView1_ModeChanged(sender As Object, e As System.EventArgs) Handles DetailsView1.ModeChanged
        EntityDataSource1.Where = "it.[ID]=" & Me.lstFilter.SelectedValue  ' DetailView.Edit work-around for lost context: Reset bound EntityDataSource.Where
Sub

【讨论】：