编写VB程序,实现如下功能:在文本框Text1中输入整数n(1≤n≤10),单击“生成矩阵”按钮Command1,生成n
2个10到99之间(包含10和99)的随机整数,并以n行、n列矩阵的形式显示在列表框List1中,再单击“对角线”按钮Command2,则在标签Label1中输出该矩阵对角线(左上角到右下角)上的数值,运行界面如图所示,程序代码如下。
(1)要使文本框Text1上显示的默认文本由“8”改为“10”,可在其属性窗口中将________属性的属性值改为“10”。

(2)为了实现上述功能,请在划线处填入合适的代码。
Const MAXNUM = 100
Dim i As Integer, n As Integer
Dim a(1 To MAXNUM ^ 2) As Integer
Private Sub Command1_Click()
Dim line As String
n = Val(Text1.Text)
line = ""
List1.Clear
Randomize
For i = 1 To n ^ 2
a(i) =
① If i > 1 And i Mod n =" 1" Then
List1.AddItem line
line = Str(a(i))
Else
line =
② End If
Next i
List1.AddItem line
End Sub
Private Sub Command2_Click()
Label1.Caption = ""
For i = 1 to
③ Label1.Caption =" Label1.Caption" & Str(a(i + (i - 1) * n))
Next i
End Sub