Expression.Constant Method (Object, Type)
[ This article is for Windows Phone 8 developers. If you’re developing for Windows 10, see the latest documentation. ]
Creates a ConstantExpression that has the Value and Type properties set to the specified values.
Assembly: System.Core (in System.Core.dll)
Parameters
- value
- Type: System.Object
An Object to set the Value property equal to.
- type
- Type: System.Type
A Type to set the Type property equal to.
Return Value
Type: System.Linq.Expressions.ConstantExpressionA ConstantExpression that has the NodeType property equal to Constant and the Value and Type properties set to the specified values.
| Exception | Condition |
|---|---|
| ArgumentNullException | type is null. |
| ArgumentException | value is not null and type is not assignable from the dynamic type of value. |
The following code example shows how to create an expression that represents a constant of the nullable type and set its value to null.
// Add the following directive to your file:
// using System.Linq.Expressions;
// This expression represents a constant value,
// for which you can explicitly specify the type.
// This can be used, for example, for defining constants of a nullable type.
Expression constantExpr = Expression.Constant(
null,
typeof(double?)
);
// Print out the expression.
outputBlock.Text += constantExpr.ToString() + "\n";
// This code example produces the following output:
//
// null
Show: