Queryable.Where Queryable.Where Queryable.Where Queryable.Where Method

定義

述語に基づいて値のシーケンスをフィルター処理します。Filters a sequence of values based on a predicate.

オーバーロード

Where<TSource>(IQueryable<TSource>, Expression<Func<TSource,Int32,Boolean>>) Where<TSource>(IQueryable<TSource>, Expression<Func<TSource,Int32,Boolean>>) Where<TSource>(IQueryable<TSource>, Expression<Func<TSource,Int32,Boolean>>) Where<TSource>(IQueryable<TSource>, Expression<Func<TSource,Int32,Boolean>>)

述語に基づいて値のシーケンスをフィルター処理します。Filters a sequence of values based on a predicate. 各要素のインデックスは、述語関数のロジックで使用されます。Each element's index is used in the logic of the predicate function.

Where<TSource>(IQueryable<TSource>, Expression<Func<TSource,Boolean>>) Where<TSource>(IQueryable<TSource>, Expression<Func<TSource,Boolean>>) Where<TSource>(IQueryable<TSource>, Expression<Func<TSource,Boolean>>) Where<TSource>(IQueryable<TSource>, Expression<Func<TSource,Boolean>>)

述語に基づいて値のシーケンスをフィルター処理します。Filters a sequence of values based on a predicate.

Where<TSource>(IQueryable<TSource>, Expression<Func<TSource,Int32,Boolean>>) Where<TSource>(IQueryable<TSource>, Expression<Func<TSource,Int32,Boolean>>) Where<TSource>(IQueryable<TSource>, Expression<Func<TSource,Int32,Boolean>>) Where<TSource>(IQueryable<TSource>, Expression<Func<TSource,Int32,Boolean>>)

述語に基づいて値のシーケンスをフィルター処理します。Filters a sequence of values based on a predicate. 各要素のインデックスは、述語関数のロジックで使用されます。Each element's index is used in the logic of the predicate function.

public:
generic <typename TSource>
[System::Runtime::CompilerServices::Extension]
 static System::Linq::IQueryable<TSource> ^ Where(System::Linq::IQueryable<TSource> ^ source, System::Linq::Expressions::Expression<Func<TSource, int, bool> ^> ^ predicate);
public static System.Linq.IQueryable<TSource> Where<TSource> (this System.Linq.IQueryable<TSource> source, System.Linq.Expressions.Expression<Func<TSource,int,bool>> predicate);
static member Where : System.Linq.IQueryable<'Source> * System.Linq.Expressions.Expression<Func<'Source, int, bool>> -> System.Linq.IQueryable<'Source>
<Extension()>
Public Function Where(Of TSource) (source As IQueryable(Of TSource), predicate As Expression(Of Func(Of TSource, Integer, Boolean))) As IQueryable(Of TSource)

型パラメーター

TSource

source の要素の型。The type of the elements of source.

パラメーター

source
IQueryable<TSource>

フィルター処理する IQueryable<T>An IQueryable<T> to filter.

predicate
Expression<Func<TSource,Int32,Boolean>>

各要素が条件を満たしているかどうかをテストする関数。この関数の 2 つ目のパラメーターは、ソース シーケンスの要素のインデックスを表します。A function to test each element for a condition; the second parameter of the function represents the index of the element in the source sequence.

戻り値

IQueryable<TSource>

predicate で指定された条件を満たす、入力シーケンスの要素を含む IQueryable<T>An IQueryable<T> that contains elements from the input sequence that satisfy the condition specified by predicate.

例外

source または predicatenull です。source or predicate is null.

次のコード例は、使用する方法を示しますWhere<TSource>(IQueryable<TSource>, Expression<Func<TSource,Int32,Boolean>>)を各要素のインデックスを組み込む述語に基づいてシーケンスをフィルター処理します。The following code example demonstrates how to use Where<TSource>(IQueryable<TSource>, Expression<Func<TSource,Int32,Boolean>>) to filter a sequence based on a predicate that incorporates the index of each element.

int[] numbers = { 0, 30, 20, 15, 90, 85, 40, 75 };

// Get all the numbers that are less than or equal to
// the product of their index in the array and 10.
IEnumerable<int> query =
    numbers.AsQueryable()
    .Where((number, index) => number <= index * 10);

foreach (int number in query)
    Console.WriteLine(number);

/*
    This code produces the following output:

    0
    20
    15
    40
*/

Dim numbers() As Integer = {0, 30, 20, 15, 90, 85, 40, 75}

' Get all the numbers that are less than or equal to
' the product of their index in the array and 10.
Dim query = numbers.AsQueryable() _
    .Where(Function(number, index) number <= index * 10)

' Display the results.
Dim output As New System.Text.StringBuilder
For Each number As Integer In query
    output.AppendLine(number)
Next
MsgBox(output.ToString())

' This code produces the following output:

' 0
' 20
' 15
' 40

注釈

このメソッドは、少なくとも 1 つのパラメーター型のExpression<TDelegate>型引数は、のいずれか、Func<T,TResult>型。This method has at least one parameter of type Expression<TDelegate> whose type argument is one of the Func<T,TResult> types. ラムダ式で、これらのパラメーターを渡すことができますにコンパイルされると、Expression<TDelegate>します。For these parameters, you can pass in a lambda expression and it will be compiled to an Expression<TDelegate>.

Where<TSource>(IQueryable<TSource>, Expression<Func<TSource,Int32,Boolean>>)メソッドを生成、MethodCallExpression呼び出しを表すWhere<TSource>(IQueryable<TSource>, Expression<Func<TSource,Int32,Boolean>>)として構築されたジェネリック メソッド自体。The Where<TSource>(IQueryable<TSource>, Expression<Func<TSource,Int32,Boolean>>) method generates a MethodCallExpression that represents calling Where<TSource>(IQueryable<TSource>, Expression<Func<TSource,Int32,Boolean>>) 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Where<TSource>(IQueryable<TSource>, Expression<Func<TSource,Int32,Boolean>>)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 Where<TSource>(IQueryable<TSource>, Expression<Func<TSource,Int32,Boolean>>) depends on the implementation of the type of the source parameter. 想定される動作はから要素が返されるsourceで指定された条件を満たすpredicateします。The expected behavior is that it returns the elements from source that satisfy the condition specified by predicate. 各ソース要素のインデックスが 2 番目の引数として提供されるpredicateします。The index of each source element is provided as the second argument to predicate.

Where<TSource>(IQueryable<TSource>, Expression<Func<TSource,Boolean>>) Where<TSource>(IQueryable<TSource>, Expression<Func<TSource,Boolean>>) Where<TSource>(IQueryable<TSource>, Expression<Func<TSource,Boolean>>) Where<TSource>(IQueryable<TSource>, Expression<Func<TSource,Boolean>>)

述語に基づいて値のシーケンスをフィルター処理します。Filters a sequence of values based on a predicate.

public:
generic <typename TSource>
[System::Runtime::CompilerServices::Extension]
 static System::Linq::IQueryable<TSource> ^ Where(System::Linq::IQueryable<TSource> ^ source, System::Linq::Expressions::Expression<Func<TSource, bool> ^> ^ predicate);
public static System.Linq.IQueryable<TSource> Where<TSource> (this System.Linq.IQueryable<TSource> source, System.Linq.Expressions.Expression<Func<TSource,bool>> predicate);
static member Where : System.Linq.IQueryable<'Source> * System.Linq.Expressions.Expression<Func<'Source, bool>> -> System.Linq.IQueryable<'Source>
<Extension()>
Public Function Where(Of TSource) (source As IQueryable(Of TSource), predicate As Expression(Of Func(Of TSource, Boolean))) As IQueryable(Of TSource)

型パラメーター

TSource

source の要素の型。The type of the elements of source.

パラメーター

source
IQueryable<TSource>

フィルター処理する IQueryable<T>An IQueryable<T> to filter.

predicate
Expression<Func<TSource,Boolean>>

各要素が条件を満たしているかどうかをテストする関数。A function to test each element for a condition.

戻り値

IQueryable<TSource>

predicate で指定された条件を満たす、入力シーケンスの要素を含む IQueryable<T>An IQueryable<T> that contains elements from the input sequence that satisfy the condition specified by predicate.

例外

source または predicatenull です。source or predicate is null.

次のコード例は、使用する方法を示しますWhere<TSource>(IQueryable<TSource>, Expression<Func<TSource,Boolean>>)シーケンスをフィルター処理します。The following code example demonstrates how to use Where<TSource>(IQueryable<TSource>, Expression<Func<TSource,Boolean>>) to filter a sequence.

List<string> fruits =
    new List<string> { "apple", "passionfruit", "banana", "mango", 
                       "orange", "blueberry", "grape", "strawberry" };

// Get all strings whose length is less than 6.
IEnumerable<string> query =
    fruits.AsQueryable().Where(fruit => fruit.Length < 6);

foreach (string fruit in query)
    Console.WriteLine(fruit);

/*
    This code produces the following output:

    apple
    mango
    grape
*/

Dim fruits As New List(Of String)(New String() _
                        {"apple", "passionfruit", "banana", "mango", _
                         "orange", "blueberry", "grape", "strawberry"})

' Get all strings whose length is less than 6.
Dim query = fruits.AsQueryable().Where(Function(fruit) fruit.Length < 6)

' Display the results.
Dim output As New System.Text.StringBuilder
For Each fruit As String In query
    output.AppendLine(fruit)
Next
MsgBox(output.ToString())

' This code produces the following output:

' apple
' mango
' grape

注釈

このメソッドは、少なくとも 1 つのパラメーター型のExpression<TDelegate>型引数は、のいずれか、Func<T,TResult>型。This method has at least one parameter of type Expression<TDelegate> whose type argument is one of the Func<T,TResult> types. ラムダ式で、これらのパラメーターを渡すことができますにコンパイルされると、Expression<TDelegate>します。For these parameters, you can pass in a lambda expression and it will be compiled to an Expression<TDelegate>.

Where<TSource>(IQueryable<TSource>, Expression<Func<TSource,Boolean>>)メソッドを生成、MethodCallExpression呼び出しを表すWhere<TSource>(IQueryable<TSource>, Expression<Func<TSource,Boolean>>)として構築されたジェネリック メソッド自体。The Where<TSource>(IQueryable<TSource>, Expression<Func<TSource,Boolean>>) method generates a MethodCallExpression that represents calling Where<TSource>(IQueryable<TSource>, Expression<Func<TSource,Boolean>>) 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Where<TSource>(IQueryable<TSource>, Expression<Func<TSource,Boolean>>)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 Where<TSource>(IQueryable<TSource>, Expression<Func<TSource,Boolean>>) depends on the implementation of the type of the source parameter. 想定される動作はから要素が返されるsourceで指定された条件を満たすpredicateします。The expected behavior is that it returns the elements from source that satisfy the condition specified by predicate.

適用対象