finding min max values an array controlling vb.net

i need min max value an array. .max duty works nonetheless .min keeps arrangement zero.

public category program_2_grade
    low max integer
    low min integer
    low normal integer
    low average1 integer
    low class string
    private servant button1_click(byval sender system.object, byval e system.eventargs) handles button1.click
        textbox1.text = zero textbox1.text > 100 then
            msgbox("doesn't accommodate class requirements", msgboxstyle.exclamation, "error")
            textbox1.clear()
            textbox1.focus()
            opposing = 0
        else
            grade_enter(counter) = textbox1.text
            textbox1.clear()
            textbox1.focus()
            opposing = opposing + 1

            opposing = grade_amount then
                max = grade_enter.max()
                min = grade_enter.min()

                i integer = 0 counter
                    normal = normal + grade_enter(i) / counter
                    average1 = average1 + grade_enter(i) - grade_enter.min / counter
                next

                name box average
                    box 30 49
                        class = "c"
                    box 50 69
                        class = "b"
                    box 70 100
                        class = "a"
                    box else
                        class = "fail"
                finish select

                (program_2.checkbox1.checked = true) then
                    program_2.textbox4.text = _
                ("name:" & " " & (program_2.textbox1.text) & vbnewline & _
                "class: " & (program_2.textbox2.text) & vbnewline & _
                "number grades:" & " " & (program_2.textbox3.text) & vbnewline & _
                "max:" & " " & max & vbnewline & _
                "min:" & " " & min & vbnewline & _
                "average:" & " " & average1 & vbnewline) & _
                "grade:" & " " & class & vbnewline & _
                "dropped lowest grade"
                else
                    program_2.textbox4.text = _
                ("name:" & " " & (program_2.textbox1.text) & vbnewline & _
                "class: " & (program_2.textbox2.text) & vbnewline & _
                "number grades:" & " " & (program_2.textbox3.text) & vbnewline & _
                "max:" & " " & max & vbnewline & _
                "min:" & " " & min & vbnewline & _
                "average:" & " " & normal & vbnewline) & _
                "grade:" & " " & class & vbnewline
                finish if

                me.close()
                normal = 0
                average1 = 0
                opposing = 0
            finish if
        finish if
    finish sub

my arrays set during tellurian scope.