ArrayIndex Method (Expression, IEnumerable(Expression))
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Expression.ArrayIndex Method (Expression, IEnumerable<Expression>)

 

Creates a MethodCallExpression that represents applying an array index operator to an array of rank more than one.

Namespace:   System.Linq.Expressions
Assembly:  System.Core (in System.Core.dll)

public static MethodCallExpression ArrayIndex(
	Expression array,
	IEnumerable<Expression> indexes
)

Parameters

array
Type: System.Linq.Expressions.Expression

An Expression to set the Object property equal to.

indexes
Type: System.Collections.Generic.IEnumerable<Expression>

An IEnumerable<T> that contains Expression objects to use to populate the Arguments collection.

Return Value

Type: System.Linq.Expressions.MethodCallExpression

A MethodCallExpression that has the NodeType property equal to Call and the Object and Arguments properties set to the specified values.

Exception Condition
ArgumentNullException

array or indexes is null.

ArgumentException

array.Type does not represent an array type.

-or-

The rank of array.Type does not match the number of elements in indexes.

-or-

The Type property of one or more elements of indexes does not represent the Int32 type.

Each element of indexes must have Type equal to Int32. The Type property of array must represent an array type whose rank matches the number of elements in indexes.

If the rank of array.Type is 1, this method returns a BinaryExpression. The Left property is set to array and the Right property is set to the single element of indexes. The Type property of the BinaryExpression represents the element type of array.Type.

If the rank of array.Type is more than one, this method returns a MethodCallExpression. The Method property is set to the MethodInfo that describes the public instance method Get on the type represented by the Type property of array.

The following example demonstrates how to use the ArrayIndex(Expression, Expression[]) method to create a MethodCallExpression that represents indexing into a two-dimensional array.

string[,] gradeArray =
    { {"chemistry", "history", "mathematics"}, {"78", "61", "82"} };

System.Linq.Expressions.Expression arrayExpression =
    System.Linq.Expressions.Expression.Constant(gradeArray);

// Create a MethodCallExpression that represents indexing
// into the two-dimensional array 'gradeArray' at (0, 2).
// Executing the expression would return "mathematics".
System.Linq.Expressions.MethodCallExpression methodCallExpression =
    System.Linq.Expressions.Expression.ArrayIndex(
        arrayExpression,
        System.Linq.Expressions.Expression.Constant(0),
        System.Linq.Expressions.Expression.Constant(2));

Console.WriteLine(methodCallExpression.ToString());

// This code produces the following output:
//
// value(System.String[,]).Get(0, 2)

Universal Windows Platform
Available since 8
.NET Framework
Available since 3.5
Portable Class Library
Supported in: portable .NET platforms
Silverlight
Available since 2.0
Windows Phone Silverlight
Available since 7.0
Windows Phone
Available since 8.1
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