求助vb里<>""什么意思啊
Option Explicit Dim sum As Double Private Sub txtChinese_Change()
sum = 0
If txtChinese <> "" Then sum = sum + Val(txtChinese)
If txtMath <> "" Then sum = sum + Val(txtMath)
If txtEnglish <> "" Then sum = sum + Val(txtEnglish) txtAvg = sum / 3
End Sub
在这段程序里 <> "" 什么意思啊 我是vb新手 求高手讲解一下