Is 运算符

Visual Basic 语言参考

Is 运算符

比较两个对象引用变量。

result = object1 Is object2

各部分说明

result

必选项。任何 Boolean 值。 

object1

必选项。任何 Object 名称。

object2

必选项。任何 Object 名称。

备注

Is 运算符确定两个对象引用是否引用同一个对象。但是，它不执行值比较。如果 object1 和 object2 都引用同一个对象，则 result 为 True；否则 result 为 False。

示例

本示例使用 Is 运算符比较两个对象引用。对象变量名称是一般的名称，仅用于说明目的。结果是 Boolean 值，它表示两个对象是否相同。

Dim myObject As New Object
Dim otherObject As New Object
Dim yourObject, thisObject, thatObject As Object
Dim myCheck As Boolean
yourObject = myObject
thisObject = myObject
thatObject = otherObject
myCheck = yourObject Is thisObject   ' Returns True.
myCheck = thatObject Is thisObject   ' Returns False.
myCheck = myObject Is thatObject ' Returns False, if myObject is not thatObject.

reference to http://msdn.microsoft.com/library/chs/default.asp?url=/library/CHS/vblr7/html/vaoprIs.asp