Represents the default value of a type or an empty expression.
Assembly: System.Core (in System.Core.dll)
Thetype exposes the following members.
|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.)|
|NodeType||Returns the node type of this expression. Extension nodes should return Extension when overriding this method. (Overrides Expression.NodeType.)|
|Type||Gets the static type of the expression that this Expression represents. (Overrides Expression.Type.)|
|Accept||Dispatches to the specific visit method for this node type. For example, MethodCallExpression calls the VisitMethodCall. (Inherited from Expression.)|
|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 it 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.)|
|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.)|
The following code example shows how to create an expression that represents a default value for a given type by using the Default method.
// Add the following directive to your file: // using System.Linq.Expressions; // This expression represents the default value of a type // (0 for integer, null for a string, etc.) Expression defaultExpr = Expression.Default( typeof(byte) ); // Print out the expression. Console.WriteLine(defaultExpr.ToString()); // The following statement first creates an expression tree, // then compiles it, and then executes it. Console.WriteLine( Expression.Lambda<Func<byte>>(defaultExpr).Compile()()); // This code example produces the following output: // // default(Byte) // 0
Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2
The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.