主题：不为空

如何做到没有填写，显示提示信息并不能提交呢？

With wb.AddInputGroup("form1","ipg1","家访信息")
                .AddInput("学生姓名","学生姓名","text") '前一个"姓名"是ID,后一个"姓名"是标题
                .AddSelect("年级","年级","|一年级|二年级|三年级|四年级|五年级|六年级|七年级|八年级|九年级")
                .AddSelect("班级","班级","|(1)班|(2)班|(3)班|(4)班|(5)班|(6)班|(7)班|(8)班")
                .AddInput("家访日期","家访日期","date")
                .AddInput("家访教师","家访教师","text")
               
                With wb.AddInputGroup("form1","ipg21","家访资料")
                    With .AddUploader("up1","家访资料",True)    'True表示可上传多个文件
                        .Accept = "image/*"   '允许使用相册和相机
                        .AllowDelete = True '允许删除
                        .Incremental = True '允许重复选择文件或连续拍照
                        '  For Each s1 As String In dr.Lines("资料")
                        '     .AddImage("./学校档案/送教记录/" & s1)
                        ' Next
                    End With
                End With