怎么判断字符串是否yyyy－mm－dd格式

如何判断字符串是否yyyy－mm－dd格式
vb     如题

[解决办法]
Function b(s As String) As Boolean

On Error GoTo 100
If s = Format(CDate(s), "yyyy-mm-dd ") Then
b = True
Else
b = False
End If
Exit Function
100:
b = False

End Function

Private Sub Command1_Click()

Dim s As String

s = "2006-3-13 "
MsgBox b(s)

s = "04/01/2006 "
MsgBox b(s)

s = "2006/04/30 "
MsgBox b(s)

s = "2006-18-51 "
MsgBox b(s)

s = "2006-04-30 "
MsgBox b(s)

End Sub

是不是要这个？
[解决办法]
Dim reg,str,match,Matches

str= "2007-04-30 "
Set reg=new regexp
reg.IgnoreCase = True
reg.pattern= "^\d{4}-\d{2}-\d{2}$ "
Set Matches = reg.Execute(str)

If(CInt(Matches.count)> =1) Then
MsgBox "匹配 "
Else
MsgBox "不匹配 "
End If