HOW TO：排序資料 (Entity Framework)

本主題將說明如何排序查詢結果。此範例會傳回依照 Contact.LastName 第一個字母的英文順序排序的 Contact 物件集合。此外，也會顯示使用下列 實體架構 查詢技術的相同範例：

• LINQ to Entities

• 使用 ObjectQuery<T> 的 Entity SQL

• ObjectQuery<T> 的查詢產生器方法

本主題的範例是根據 Adventure Works Sales Model。若要執行此範例中的程式碼，您必須已經將 AdventureWorks Sales Model 加入到專案中，並設定您的專案使用 Entity Framework。若要這樣做，請完成 HOW TO：手動設定 Entity Framework 專案和 HOW TO：以手動方式定義 Entity Data Model (Entity Framework) 中的程序。您也可以使用 [Entity Data Model 精靈] 來定義 AdventureWorks Sales Model。如需詳細資訊，請參閱 HOW TO：使用 Entity Data Model 精靈 (Entity Framework)。

範例

以下是 LINQ 到實體 範例。

Using context As AdventureWorksEntities = _
  New AdventureWorksEntities()
    Try
        ' Define a query that returns a list 
        ' of Contact objects sorted by last name.
        Dim sortedNames = _
        From n In context.Contact _
        Order By n.LastName _
        Select n

        Console.WriteLine("The sorted list of last names:")
        For Each name As Contact In sortedNames
            Console.WriteLine(name.LastName)
        Next
    Catch ex As EntitySqlException
        Console.WriteLine(ex.ToString())
    End Try
End Using

using (AdventureWorksEntities context = 
    new AdventureWorksEntities())
{
    try
    {
        // Define a query that returns a list 
        // of Contact objects sorted by last name.
        var sortedNames =
            from n in context.Contact
            orderby n.LastName
            select n;

        Console.WriteLine("The sorted list of last names:");
        foreach (Contact name in sortedNames)
        {
            Console.WriteLine(name.LastName);
        }
    }
    catch (EntitySqlException ex)
    {
        Console.WriteLine(ex.ToString());
    }
}

以下是 實體 SQL 範例。

' Define the Entity SQL query string that returns 
' Contact objects sorted by last name.
Dim queryString As String = "SELECT VALUE n FROM Contact AS n " _
        + "Order By n.LastName"

Using context As AdventureWorksEntities = _
    New AdventureWorksEntities()
    Try
        ' Define an ObjectQuery that returns a collection 
        ' of Contact objects sorted by last name.
        Dim query As ObjectQuery(Of Contact) = _
            New ObjectQuery(Of Contact)(queryString, context)

        Console.WriteLine("The sorted list of last names:")
        For Each name As Contact _
        In query.Execute(MergeOption.AppendOnly)
            Console.WriteLine(name.LastName)
        Next
    Catch ex As EntitySqlException
        Console.WriteLine(ex.ToString())
    End Try
End Using

// Define the Entity SQL query string that returns 
// Contact objects sorted by last name.
string queryString = @"SELECT VALUE n FROM Contact AS n 
        Order By n.LastName";

using (AdventureWorksEntities context =
    new AdventureWorksEntities())
{
    try
    {
        // Define an ObjectQuery that returns a collection 
        // of Contact objects sorted by last name.
        ObjectQuery<Contact> query = 
            new ObjectQuery<Contact>(queryString, context);

        Console.WriteLine("The sorted list of last names:");
        foreach (Contact name in query.Execute(MergeOption.AppendOnly))
        {
            Console.WriteLine(name.LastName);
        }
    }
    catch (EntitySqlException ex)
    {
        Console.WriteLine(ex.ToString());
    }
}

以下是查詢產生器方法範例。

Using context As AdventureWorksEntities = _
    New AdventureWorksEntities()
    Try
        ' Define an ObjectQuery that returns a collection 
        ' of Contact objects sorted by last name.
        Dim query As ObjectQuery(Of Contact) = _
        context.Contact.OrderBy("it.LastName")

        Console.WriteLine("The sorted list of last names:")
        For Each name As Contact _
        In query.Execute(MergeOption.AppendOnly)
            Console.WriteLine(name.LastName)
        Next
    Catch ex As EntitySqlException
        Console.WriteLine(ex.ToString())
    End Try
End Using

using (AdventureWorksEntities context =
    new AdventureWorksEntities())
{
    try
    {
        // Define an ObjectQuery that returns a collection 
        // of Contact objects sorted by last name.
        ObjectQuery<Contact> query = 
            context.Contact.OrderBy("it.LastName");

        Console.WriteLine("The sorted list of last names:");
        foreach (Contact name in query.Execute(MergeOption.AppendOnly))
        {
            Console.WriteLine(name.LastName);
        }
    }
    catch (EntitySqlException ex)
    {
        Console.WriteLine(ex.ToString());
    }
}

另請參閱

其他資源

查詢 Entity Data Model (Entity Framework 工作)