Private Sub Form1_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles MyBase.Load
        Dim i, i1, i2 As Integer
        Dim ss As String
        i = CInt(InputBox("请输入一个整数", "Input", "2"))
        i1 = i
        For i1 = 1 To i
            ss = ""
            For i2 = 1 To i
                ss = ss & "*"
            Next
            Console.WriteLine(ss)
        Next
        Console.ReadLine()
    End Sub

我试了不对啊

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        Dim i, j, m As Integer
        Dim ss As String
        m = CInt(InputBox("请输入一个整数", "Input", "2"))
        For i = 1 To m
            For j = 1 To m
                ss &= "*"
            Next
            ss &= vbNewLine
        Next
        TextBox1.Text = ss ’这里TextBox1.Multiline = True
    End Sub

不好意思，米看到是用控制台程序，那就改成：
Private Sub Form3_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
       
        Dim i, j, m As Integer
        Dim ss As String
        m = CInt(InputBox("请输入一个整数", "Input", "2"))
        For i = 1 To m
            For j = 1 To m
                ss &= "*"
            Next
            ss &= vbNewLine
        Next
        Console.WriteLine(ss)
        Console.ReadLine()
    End Sub