VBScript字典存在方法始终返回True

Question

我究竟做错了什么？从我的测试中,objDic.exists永远不会给出错误!

    dim objDic

    set objDic = createobject("scripting.dictionary")

    objDic.add "test","I have not been deleted"

    wscript.echo objDic.item("test") 'Displays -- I have not been deleted

    objDic.remove "test"

    wscript.echo """" & objDic.item("test") & """" 'Displays -- ""

    if objDic.exists("test") then wscript.echo """" & objDic.item("test") & """" 'Displays -- ""

Answer 1

就像我所知,一个字典对象密钥只是通过引用它来创建,就好像它确实存在一样.

wscript.echo objDic.Item("test") 'Creates the key whether it exists or not
wscript.echo objDic.Exists("test") 'Will now return true

这里有一些代码可以用来证明/测试我的理论.我通常使用MsgBox而不是WScript.Echo,正如您将在我的代码中看到的那样.

dim objDic, brk
brk = vbcrlf & vbcrlf
set objDic = createobject("scripting.dictionary")
objDic.add "test","I have not been deleted"
wscript.echo "objDic.Exists(""test""): " & brk & objDic.item("test")
WScript.Echo "Now going to Remove the key named: test"
objDic.remove "test"
MsgBox "objDic.Exists(""test""): " & brk & objDic.Exists("test") 'Returns False
wscript.echo "objDic.item(""test""): " & brk & objDic.item("test") 'Shows Blank, Creates the key again with a blank value
wscript.echo "objDic.item(""NeverAdded""): " & brk & objDic.item("NeverAdded") 'Also shows blank, does not return an error
MsgBox "objDic.Exists(""test""): " & brk & objDic.Exists("test") 'Returns True