Queryable.OfType(IQueryable) Queryable.OfType(IQueryable) Queryable.OfType(IQueryable) Queryable.OfType(IQueryable) Method

Definition

指定された型に基づいて IQueryable の要素をフィルター処理します。 Filters the elements of an IQueryable based on a specified type.

public:
generic <typename TResult>
[System::Runtime::CompilerServices::Extension]
 static System::Linq::IQueryable<TResult> ^ OfType(System::Linq::IQueryable ^ source);
public static System.Linq.IQueryable<TResult> OfType<TResult> (this System.Linq.IQueryable source);
static member OfType : System.Linq.IQueryable -> System.Linq.IQueryable<'Result>
<Extension()>
Public Function OfType(Of TResult) (source As IQueryable) As IQueryable(Of TResult)

Type Parameters

TResult

シーケンスの要素をフィルター処理する型。 The type to filter the elements of the sequence on.

パラメーター

source
IQueryable IQueryable IQueryable IQueryable

フィルター処理する要素を含む IQueryable An IQueryable whose elements to filter.

Returns

IQueryable<TResult>

source 型を持つ、TResult の要素を含むコレクション。 A collection that contains the elements from source that have type TResult.

Exceptions

Examples

次のコード例は、使用する方法を示しますOfTypeいない型の要素を除外するPropertyInfo型の要素の一覧からMemberInfoします。The following code example demonstrates how to use OfType to filter out elements that are not of type PropertyInfo from a list of elements of type MemberInfo.

// Create a list of MemberInfo objects.
List<System.Reflection.MemberInfo> members = typeof(String).GetMembers().ToList();

// Return only those items that can be cast to type PropertyInfo.
IQueryable<System.Reflection.PropertyInfo> propertiesOnly =
    members.AsQueryable().OfType<System.Reflection.PropertyInfo>();

Console.WriteLine("Members of type 'PropertyInfo' are:");
foreach (System.Reflection.PropertyInfo pi in propertiesOnly)
    Console.WriteLine(pi.Name);

/*
    This code produces the following output:
 
    Members of type 'PropertyInfo' are:
    Chars
    Length
*/

' Create a list of MemberInfo objects.
Dim members As List(Of System.Reflection.MemberInfo) = GetType(String).GetMembers().ToList()

' Return only those items that can be cast to type PropertyInfo.
Dim propertiesOnly As IQueryable(Of System.Reflection.PropertyInfo) = _
        members.AsQueryable().OfType(Of System.Reflection.PropertyInfo)()

Dim output As New System.Text.StringBuilder
output.AppendLine("Members of type 'PropertyInfo' are:")
For Each pi As System.Reflection.PropertyInfo In propertiesOnly
    output.AppendLine(pi.Name)
Next

' Display the output.
MsgBox(output.ToString())

' This code produces the following output:

' Members of type 'PropertyInfo' are:
' Chars
' Length

Remarks

OfTypeメソッドを生成、MethodCallExpression呼び出しを表すOfTypeとして構築されたジェネリック メソッド自体。The OfType method generates a MethodCallExpression that represents calling OfType itself as a constructed generic method. これは、後、渡します、MethodCallExpressionCreateQuery(Expression)のメソッド、IQueryProviderによって表される、Providerのプロパティ、sourceパラメーター。It then passes the MethodCallExpression to the CreateQuery(Expression) method of the IQueryProvider represented by the Provider property of the source parameter.

呼び出し元を表す式ツリーを実行した結果として発生するクエリの動作OfTypeの型の実装によって異なります、sourceパラメーター。The query behavior that occurs as a result of executing an expression tree that represents calling OfType depends on the implementation of the type of the source parameter. 想定される動作は任意の要素をフィルター処理してsourceは型のないTResultします。The expected behavior is that it filters out any elements in source that are not of type TResult.

Applies to