Expression.ArrayAccess 方法

參考

定義

命名空間:: System.Linq.Expressions

組件:: System.Linq.Expressions.dll

組件:: System.Core.dll

組件:: netstandard.dll

重要

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建立 IndexExpression 以存取陣列。

多載

ArrayAccess(Expression, IEnumerable<Expression>)	建立 IndexExpression 以存取多維陣列。
ArrayAccess(Expression, Expression[])	建立 IndexExpression 以存取陣列。

ArrayAccess(Expression, IEnumerable<Expression>)

來源:: IndexExpression.cs

來源:: IndexExpression.cs

來源:: IndexExpression.cs

建立 IndexExpression 以存取多維陣列。

public:
 static System::Linq::Expressions::IndexExpression ^ ArrayAccess(System::Linq::Expressions::Expression ^ array, System::Collections::Generic::IEnumerable<System::Linq::Expressions::Expression ^> ^ indexes);

public static System.Linq.Expressions.IndexExpression ArrayAccess (System.Linq.Expressions.Expression array, System.Collections.Generic.IEnumerable<System.Linq.Expressions.Expression> indexes);

public static System.Linq.Expressions.IndexExpression ArrayAccess (System.Linq.Expressions.Expression array, System.Collections.Generic.IEnumerable<System.Linq.Expressions.Expression>? indexes);

static member ArrayAccess : System.Linq.Expressions.Expression * seq<System.Linq.Expressions.Expression> -> System.Linq.Expressions.IndexExpression

Public Shared Function ArrayAccess (array As Expression, indexes As IEnumerable(Of Expression)) As IndexExpression

參數

array: Expression

表示多維陣列的運算式。

indexes: IEnumerable<Expression>

包含用於對陣列進行索引之運算式的 IEnumerable<T>。

傳回

IndexExpression

建立的 IndexExpression。

範例

下列程式代碼範例示範如何使用方法來變更多維度陣列 ArrayAccess 中元素的值。

// Add the following directive to your file:
// using System.Linq.Expressions;

// This parameter expression represents a variable that will hold the two-dimensional array.
ParameterExpression arrayExpr = Expression.Parameter(typeof(int[,]), "Array");

// This parameter expression represents a first array index.
ParameterExpression firstIndexExpr = Expression.Parameter(typeof(int), "FirstIndex");
// This parameter expression represents a second array index.
ParameterExpression secondIndexExpr = Expression.Parameter(typeof(int), "SecondIndex");

// The list of indexes.
List<Expression> indexes = new List<Expression> { firstIndexExpr, secondIndexExpr };

// This parameter represents the value that will be added to a corresponding array element.
ParameterExpression valueExpr = Expression.Parameter(typeof(int), "Value");

// This expression represents an access operation to a multidimensional array.
// It can be used for assigning to, or reading from, an array element.
Expression arrayAccessExpr = Expression.ArrayAccess(
    arrayExpr,
    indexes
);

// This lambda expression assigns a value provided to it to a specified array element.
// The array, the index of the array element, and the value to be added to the element
// are parameters of the lambda expression.
Expression<Func<int[,], int, int, int, int>> lambdaExpr =
    Expression.Lambda<Func<int[,], int, int, int, int>>(
        Expression.Assign(arrayAccessExpr, Expression.Add(arrayAccessExpr, valueExpr)),
        arrayExpr,
        firstIndexExpr,
        secondIndexExpr,
        valueExpr
);

// Print out expressions.
Console.WriteLine("Array Access Expression:");
Console.WriteLine(arrayAccessExpr.ToString());

Console.WriteLine("Lambda Expression:");
Console.WriteLine(lambdaExpr.ToString());

Console.WriteLine("The result of executing the lambda expression:");

// The following statement first creates an expression tree,
// then compiles it, and then executes it.
// Parameters passed to the Invoke method are passed to the lambda expression.
int[,] sampleArray = { {10,  20,   30},
                       {100, 200, 300}};
Console.WriteLine(lambdaExpr.Compile().Invoke(sampleArray, 1, 1, 5));

// This code example produces the following output:
//
// Array Access Expression:
// Array[FirstIndex, SecondIndex]

// Lambda Expression:
// (Array, FirstIndex, SecondIndex Value) =>
// (Array[FirstIndex, SecondIndex] = (Array[FirstIndex, SecondIndex] + Value))

// The result of executing the lambda expression:
// 205

' Add the following directive to your file:
' Imports System.Linq.Expressions  

' This parameter expression represents a variable that will hold the two-dimensional array.
Dim arrayExpr As ParameterExpression = Expression.Parameter(GetType(Integer(,)), "Array")

' This parameter expression represents a first array index.            
Dim firstIndexExpr As ParameterExpression = Expression.Parameter(GetType(Integer), "FirstIndex")
' This parameter expression represents a second array index.            
Dim secondIndexExpr As ParameterExpression = Expression.Parameter(GetType(Integer), "SecondIndex")

' The list of indexes.
Dim indexes As List(Of Expression) = New List(Of Expression) From
    {firstIndexExpr, secondIndexExpr}

' This parameter represents the value that will be added to a corresponding array element.
Dim valueExpr As ParameterExpression = Expression.Parameter(GetType(Integer), "Value")

' This expression represents an access operation to a multidimensional array.
' It can be used for assigning to, or reading from, an array element.
Dim arrayAccessExpr As Expression = Expression.ArrayAccess(
    arrayExpr,
    indexes
)

' This lambda expression assigns a value provided to it to a specified array element.
' The array, the index of the array element, and the value to be added to the element
' are parameters of the lambda expression.
Dim lambdaExpr As Expression(Of Func(Of Integer(,), Integer, Integer, Integer, Integer)) =
    Expression.Lambda(Of Func(Of Integer(,), Integer, Integer, Integer, Integer))(
        Expression.Assign(arrayAccessExpr, Expression.Add(arrayAccessExpr, valueExpr)),
        arrayExpr,
        firstIndexExpr,
        secondIndexExpr,
        valueExpr
)

' Print expressions.
Console.WriteLine("Array Access Expression:")
Console.WriteLine(arrayAccessExpr.ToString())

Console.WriteLine("Lambda Expression:")
Console.WriteLine(lambdaExpr.ToString())

Console.WriteLine("The result of executing the lambda expression:")

' The following statement first creates an expression tree,
' then compiles it, and then executes it.
' Parameters passed to the Invoke method are passed to the lambda expression.
Dim sampleArray = {{10, 20, 30},
                       {100, 200, 300}}
Console.WriteLine(lambdaExpr.Compile().Invoke(sampleArray, 1, 1, 5))

' This code example produces the following output:
'
' Array Access Expression:
' Array[FirstIndex, SecondIndex]

' Lambda Expression:
' (Array, FirstIndex, SecondIndex Value) => 
' (Array[FirstIndex, SecondIndex] = (Array[FirstIndex, SecondIndex] + Value))

' The result of executing the lambda expression:
' 205

備註

您可以使用方法，或透過 NewArrayBounds 或NewArrayInit取得表示數位的MakeMemberAccess運算式。

適用於

ArrayAccess(Expression, Expression[])

來源:: IndexExpression.cs

來源:: IndexExpression.cs

來源:: IndexExpression.cs

建立 IndexExpression 以存取陣列。

public:
 static System::Linq::Expressions::IndexExpression ^ ArrayAccess(System::Linq::Expressions::Expression ^ array, ... cli::array <System::Linq::Expressions::Expression ^> ^ indexes);

public static System.Linq.Expressions.IndexExpression ArrayAccess (System.Linq.Expressions.Expression array, params System.Linq.Expressions.Expression[] indexes);

public static System.Linq.Expressions.IndexExpression ArrayAccess (System.Linq.Expressions.Expression array, params System.Linq.Expressions.Expression[]? indexes);

static member ArrayAccess : System.Linq.Expressions.Expression * System.Linq.Expressions.Expression[] -> System.Linq.Expressions.IndexExpression

Public Shared Function ArrayAccess (array As Expression, ParamArray indexes As Expression()) As IndexExpression

參數

array: Expression

表示要編制索引之陣列的運算式。

indexes: Expression[]

包含用於對陣列進行索引之運算式的陣列。

傳回

IndexExpression

建立的 IndexExpression。

範例

下列程式代碼範例示範如何使用方法來變更數位元素 ArrayAccess 的值。

// Add the following directive to your file:
// using System.Linq.Expressions;

// This parameter expression represents a variable that will hold the array.
ParameterExpression arrayExpr = Expression.Parameter(typeof(int[]), "Array");

// This parameter expression represents an array index.
ParameterExpression indexExpr = Expression.Parameter(typeof(int), "Index");

// This parameter represents the value that will be added to a corresponding array element.
ParameterExpression valueExpr = Expression.Parameter(typeof(int), "Value");

// This expression represents an array access operation.
// It can be used for assigning to, or reading from, an array element.
Expression arrayAccessExpr = Expression.ArrayAccess(
    arrayExpr,
    indexExpr
);

// This lambda expression assigns a value provided to it to a specified array element.
// The array, the index of the array element, and the value to be added to the element
// are parameters of the lambda expression.
Expression<Func<int[], int, int, int>> lambdaExpr = Expression.Lambda<Func<int[], int, int, int>>(
    Expression.Assign(arrayAccessExpr, Expression.Add(arrayAccessExpr, valueExpr)),
    arrayExpr,
    indexExpr,
    valueExpr
);

// Print out expressions.
Console.WriteLine("Array Access Expression:");
Console.WriteLine(arrayAccessExpr.ToString());

Console.WriteLine("Lambda Expression:");
Console.WriteLine(lambdaExpr.ToString());

Console.WriteLine("The result of executing the lambda expression:");

// The following statement first creates an expression tree,
// then compiles it, and then executes it.
// Parameters passed to the Invoke method are passed to the lambda expression.
Console.WriteLine(lambdaExpr.Compile().Invoke(new int[] { 10, 20, 30 }, 0, 5));

// This code example produces the following output:
//
// Array Access Expression:
// Array[Index]

// Lambda Expression:
// (Array, Index, Value) => (Array[Index] = (Array[Index] + Value))

// The result of executing the lambda expression:
// 15

' Add the following directive to your file:
' Imports System.Linq.Expressions  

' This parameter expression represents a variable that will hold the array.
Dim arrayExpr As ParameterExpression = Expression.Parameter(GetType(Integer()), "Array")

' This parameter expression represents an array index.
' For multidimensional arrays, you can define several indexes. 
Dim indexExpr As ParameterExpression = Expression.Parameter(GetType(Integer), "Index")

' This parameter represents the value that will be added to a corresponding array element.
Dim valueExpr As ParameterExpression = Expression.Parameter(GetType(Integer), "Value")

' This expression represents an array access operation.
' It can be used for assigning to, or reading from, an array element.
Dim arrayAccessExpr As Expression = Expression.ArrayAccess(
    arrayExpr,
    indexExpr
)

' This lambda expression assigns a value provided to it to a specified array element.
' The array, the index of the array element, and the value to be added to the element
' are parameters of the lambda expression.
Dim lambdaExpr As Expression(Of Func(Of Integer(), Integer, Integer, Integer)) =
    Expression.Lambda(Of Func(Of Integer(), Integer, Integer, Integer))(
        Expression.Assign(arrayAccessExpr, Expression.Add(arrayAccessExpr, valueExpr)),
    arrayExpr,
    indexExpr,
    valueExpr
  )

' Print expressions.
Console.WriteLine("Array Access Expression:")
Console.WriteLine(arrayAccessExpr.ToString())

Console.WriteLine("Lambda Expression:")
Console.WriteLine(lambdaExpr.ToString())

Console.WriteLine("The result of executing the lambda expression:")

' The following statement first creates an expression tree,
' then compiles it, and then executes it.
' Parameters passed to the Invoke method are passed to the lambda expression.
Console.WriteLine(lambdaExpr.Compile().Invoke(New Integer() {10, 20, 30}, 0, 5))

' This code example produces the following output:
'
' Array Access Expression:
' Array[Index]

' Lambda Expression:
' (Array, Index, Value) => (Array[Index] = (Array[Index] + Value))

' The result of executing the lambda expression:
' 15

備註

您可以使用方法，或透過 NewArrayBounds 或NewArrayInit取得表示數位的MakeMemberAccess運算式。

如果是多維度陣列，請使用 ArrayAccess 方法。

適用於

共用方式為

Expression.ArrayAccess 方法

定義

多載

ArrayAccess(Expression, IEnumerable<Expression>)

參數

傳回

範例

備註

適用於

ArrayAccess(Expression, Expression[])

參數

傳回

範例

備註

適用於

其他資源