学生信息管理---优化添加班级信息

本窗体优化的内容：
1.班号，教室，班主任文本框的输入限制，如：只能输入数字或汉字
2.年级comboBox中禁止输入，只能选择已经加载的内容—把style属性为2
3.窗体禁止改变大小—把borderStyle属性改为1
4.使子窗体显示在中间位置

Me.Move ((fMainForm.Width - Me.Width) / 2), ((fMainForm.Height - Me.Height) / 3)

下方是本窗体的代码，仅供参考！

Private Sub Command1_Click()
    Dim mrc As ADODB.Recordset
    Dim MsgText As String
    Dim txtSQL As String

    '防止输入框为空
    If Not Testtxt(txtClassno.Text) Then
        MsgBox "请输入班号！", vbOKOnly + vbExclamation, "警告"
        txtClassno.SetFocus
        Exit Sub
    End If



     '添加前确保该班号不存在
    txtSQL = "select * from class_Info "
    Set mrc = ExecuteSQL(txtSQL, MsgText)

    '数据库的记录指到第一条
    mrc.MoveFirst


    While (mrc.EOF = False)
        If (Trim(mrc.Fields(0)) = Trim(txtClassno.Text)) Then
            MsgBox "班号已经存在，请重新输入班号！", vbOKOnly + vbExclamation, "警告"

            Exit Sub
            txtClassno.Text = ""
            txtClassno.SetFocus
        Else
            mrc.MoveNext
        End If
    Wend

    '添加前确保该教室没有被占用
       mrc.MoveFirst


    While (mrc.EOF = False)
        If (Trim(mrc.Fields(3)) = Trim(txtClassroom.Text)) Then
            MsgBox "教室已经存在，请重新输入班号！", vbOKOnly + vbExclamation, "警告"

            Exit Sub
            txtClassno.Text = ""
            txtClassno.SetFocus
        Else
            mrc.MoveNext
        End If
    Wend


    '把班号，年级，班主任，教室中的数据添加到数据库中
    mrc.AddNew
    mrc.Fields(0) = Trim(txtClassno.Text)
    mrc.Fields(1) = Trim(comboGrade.Text)
    mrc.Fields(2) = Trim(txtDirector.Text)
    mrc.Fields(3) = Trim(txtClassroom.Text)
    mrc.Update
    mrc.Close
    MsgBox "添加班级信息成功！", vbOKOnly + vbExclamation, "添加班级信息"

End Sub

Private Sub Command2_Click()
    Unload Me
End Sub


Private Sub Form_Load()
    '先向年级（comboGrade）中加载数据
    comboGrade.AddItem "初中一年级"
    comboGrade.AddItem "初中二年级"
    comboGrade.AddItem "初中三年级"
    comboGrade.AddItem "高中一年级"
    comboGrade.AddItem "高中二年级"
    comboGrade.AddItem "高中三年级"

    '设置窗体大小和显示的位置
    Me.Height = 7875
    Me.Width = 10350
    Me.Move ((fMainForm.Width - Me.Width) / 2), ((fMainForm.Height - Me.Height) / 3)
End Sub




'限制文本框输入
Private Sub txtClassno_KeyPress(KeyAscii As Integer)

    '只能输入数字和退格键
    If KeyAscii = 8 Then
    ElseIf KeyAscii < 48 Or KeyAscii > 57 Then KeyAscii = 0
    End If

    '文本框只能输入5个字符，如果超出则不能输入并且提示用户
    If Len(txtClassno.Text) > 5 Then
    KeyAscii = 0
    MsgBox "班号字数超出"
    End If

End Sub



'限制文本框输入
Private Sub txtClassroom_KeyPress(KeyAscii As Integer)
    '只能输入数字和退格键
    If KeyAscii = 8 Then
    ElseIf KeyAscii < 48 Or KeyAscii > 57 Then KeyAscii = 0
    End If

     '文本框只能输入5个字符，如果超出则不能输入并且提示用户
    If Len(txtClassroom.Text) > 5 Then
    KeyAscii = 0
    MsgBox "教室字数超出"
    End If

End Sub


'限制文本框输入
Private Sub txtDirector_KeyPress(KeyAscii As Integer)

    '只能输入汉字和退格键
    If KeyAscii >= -20319 And KeyAscii <= -3652 Or KeyAscii = 8 Then
    Else
    KeyAscii = 0
    End If

    '文本框只能输入6个字符，如果超出则不能输入并且提示用户
    If Len(txtDirector.Text) >= 6 Then
    KeyAscii = 0
    MsgBox "名字太长，这是中国版本!"
    End If

End Sub