求VB简单代码一个

简单点的一个按钮两个TEXTBOX
Private Sub Command1_Click()
Dim sum As Long
Dim n As Integer
Dim i As Integer
n = Val(Text1.Text)
For i = 1 To n
sum = sum + i
Next i
Text2.Text = sum
End Sub

或者一个按钮一个TEXTBOX，用到INPUTBOX

Private Sub Command1_Click()
Dim sum As Long
Dim s As String
Dim n As Integer
Dim i As Integer
s = InputBox("请输入数字", "数字输入框")
n = Val(s)
For i = 1 To n
sum = sum + i
Next i
Text1.Text = sum
End Sub

窗体上只需放一个按钮。代码如下。已经运行检验了。
Private Sub Command1_Click()
Dim s As String, n As Long, flag As Boolean, sum As Long, i As Integer
Do
s = InputBox("请输入累加的终止数值（>4且<32768,整数）：", , 10)
If IsNumeric(s) Then
If Len(s) < 6 Then
n = Int(s)
If n > 4 And n <= 32767 Then flag = True
End If