Private Sub Command1_Click()
a = Val(Text1)
b = Val(Text2)
c = Val(Text3)
If a + b <= c Or a + c <= b Or b + c <= a Then
y = "不能构成三角形"
Else
If a = b = c Then
y = "等边三角形"
End If
If (a = b And a <> c) Or (a = c And a <> b) Or (b = c And b <> a) Then
y = "等腰三角形"
End If

If (a ^ 2 + b ^ 2 = c ^ 2 And a <> b) Or (a ^ 2 + c ^ 2 = b ^ 2 And a <> c) Or (b ^ 2 + c ^ 2 = a ^ 2 And b <> c) Then
y = "直角三角形"
End If
If (a ^ 2 + b ^ 2 = c ^ 2 And a = b) Or (a ^ 2 + c ^ 2 = b ^ 2 And a = c) Or (b ^ 2 + c ^ 2 = a ^ 2 And b = c) Then
y = "等腰直角三角形"
Else

y = "一般三角形"
End If
End If
Picture1.Print y
End Sub

If (a ^ 2 + b ^ 2 = c ^ 2 And a = b) Or (a ^ 2 + c ^ 2 = b ^ 2 And a = c) Or (b ^ 2 + c ^ 2 = a ^ 2 And b = c) Then
y = "等腰直角三角形"
Else

y = "一般三角形"
End If

变量作用域定义

Private Sub Command1_Click()
Dim a, b, c, y As String
a = Val(Text1.Text)
b = Val(Text2.Text)
c = Val(Text3.Text)
If a + b <= c Or a + c <= b Or b + c <= a Then
y = "不能构成三角形"
ElseIf a = b And a = c And b = c Then
y = "等边三角形"
ElseIf (a = b And a <> c) Or (a = c And a <> b) Or (b = c And b <> a) Then
y = "等腰三角形"
ElseIf (a ^ 2 + b ^ 2 = c ^ 2 And a <> b) Or (a ^ 2 + c ^ 2 = b ^ 2 And a <> c) Or (b ^ 2 + c ^ 2 = a ^ 2 And b <> c) Then
y = "直角三角形"
ElseIf (a ^ 2 + b ^ 2 = c ^ 2 And a = b) Or (a ^ 2 + c ^ 2 = b ^ 2 And a = c) Or (b ^ 2 + c ^ 2 = a ^ 2 And b = c) Then
y = "等腰直角三角形"
Else
y = "一般三角形"
End If
Text4.Text = y
End Sub


应该是这样子的 吧