最近发现了vb于是想学

但是if语句出了问题，有没有大佬解答一下

Private Sub Command1_Click()
b = Val(Text1.Text)
If (ch = 1) Then
	Text3.Text = a + b
ElseIf (ch = 2) Then
	Text3.Text = a - b
ElseIf (ch = 3) Then
	Text3.Text = a * b
ElseIf (ch = 4) Then
	Text3.Text = a / b
End If
End Sub