ConditionalExpression Class
[ This article is for Windows Phone 8 developers. If you’re developing for Windows 10, see the latest documentation. ]
Represents an expression that has a conditional operator.
Assembly: System.Core (in System.Core.dll)
The ConditionalExpression type exposes the following members.
| Name | Description | |
|---|---|---|
![]() | CanReduce | Indicates that the node can be reduced to a simpler node. If this returns true, Reduce() can be called to produce the reduced form. (Inherited from Expression.) |
![]() | IfFalse | Gets the expression to execute if the test evaluates to false. |
![]() | IfTrue | Gets the expression to execute if the test evaluates to true. |
![]() | NodeType | Returns the node type of this expression. Extension nodes should return Extension when overriding this method. (Overrides Expression.NodeType.) |
![]() | Test | Gets the test of the conditional operation. |
![]() | Type | Gets the static type of the expression that this Expression represents. (Overrides Expression.Type.) |
| Name | Description | |
|---|---|---|
![]() | Accept | Dispatches to the specific visit method for this node type. For example, MethodCallExpression calls the VisitMethodCall. (Overrides Expression.Accept(ExpressionVisitor).) |
![]() | Equals(Object) | Determines whether the specified Object is equal to the current Object. (Inherited from Object.) |
![]() | Finalize | Allows an object to try to free resources and perform other cleanup operations before the Object is reclaimed by garbage collection. (Inherited from Object.) |
![]() | GetHashCode | Serves as a hash function for a particular type. (Inherited from Object.) |
![]() | GetType | Gets the Type of the current instance. (Inherited from Object.) |
![]() | MemberwiseClone | Creates a shallow copy of the current Object. (Inherited from Object.) |
![]() | Reduce | Reduces this node to a simpler expression. If CanReduce returns true, this should return a valid expression. This method can return another node which itself must be reduced. (Inherited from Expression.) |
![]() | ReduceAndCheck | Reduces this node to a simpler expression. If CanReduce returns true, this should return a valid expression. This method can return another node which itself must be reduced. (Inherited from Expression.) |
![]() | ReduceExtensions | Reduces the expression to a known node type (that is not an Extension node) or just returns the expression if it is already a known type. (Inherited from Expression.) |
![]() | ToString | Returns a textual representation of the Expression. (Inherited from Expression.) |
![]() | Update | Creates a new expression that is like this one, but using the supplied children. If all of the children are the same, it will return this expression |
![]() | VisitChildren | Reduces the node and then calls the visitor delegate on the reduced expression. The method throws an exception if the node is not reducible. (Inherited from Expression.) |
Use the Condition factory method to create a ConditionalExpression.
The NodeType of a ConditionalExpression is Conditional.
The following code example shows how to create an expression that represents a conditional statement. If the first argument evaluates to true, the second argument is executed; otherwise, the third argument is executed.
// Add the following directive to your file: // using System.Linq.Expressions; int num = 100; // This expression represents a conditional operation. // It evaluates the test (first expression) and // executes the iftrue block (second argument) if the test evaluates to true, // or the iffalse block (third argument) if the test evaluates to false. Expression conditionExpr = Expression.Condition( Expression.Constant(num > 10), Expression.Constant("num is greater than 10"), Expression.Constant("num is smaller than 10") ); // Print out the expression. outputBlock.Text += conditionExpr.ToString() + "\n"; // The following statement first creates an expression tree, // then compiles it, and then executes it. outputBlock.Text += Expression.Lambda<Func<string>>(conditionExpr).Compile()() + "\n"; // This code example produces the following output: // // IIF("True", "num is greater than 10", "num is smaller than 10") // num is greater than 10


