程序代码：

Option Explicit

Private Sub Command1_Click()
Dim a, b, c As Integer
a = Text1
b = Text2
c = Text3
If a + b > c And a + c > b And b + c > a Then
If a = b = c Then
L5 = "等边三角形"
ElseIf (a = b And b <> c) Or (a = c And c <> b) Or (b = c And b <> a) Then
L5 = "等腰三角形"
End If
Else
L5 = "不构成三角形"
End If
End Sub