哪里出错啦，为何不执行else中想数据库插入数据的语句

Question

protected void ImageButton_register_Click(object sender, ImageClickEventArgs e)
    {
        DataClassesDataContext db = new DataClassesDataContext();
        string newpassword = this.TBpassw.Text.Trim();
        string password = this.TBpassword.Text.Trim();
        string usernm = this.TBusername.Text.Trim();
        string userrealnm = this.TBrealname.Text.Trim();
        
        string usermessage = this.TBmember_message.Text.Trim();
        Login user1 = db.Login.Where(u => u.User_Name == usernm).First();
        try
        {
            if (usernm != string.Empty && userrealnm != string.Empty && usermessage != string.Empty)
            {
                if (newpassword == password)
                {
                    var newinfo1 = new Login
                    {
                        User_Name = TBusername.Text,
                        User_Password = TBpassw.Text,
                        User_Type = "user"
                    };
                    var newfamilymember = new Family_Member
                    {
                        User_Name = TBusername.Text,
                        Family_Member_Real_Name = TBrealname.Text,
                        Family_Member_Message = TBmember_message.Text
                    };
                   
                    if (user1 != null)
                    {
                        Response.Write("<script>alert('用户名已存在，请重新输入！')</script>");
                    }
                    else
                    {
                        db.Login.InsertOnSubmit(newinfo1);
                        db.SubmitChanges();
                        db.Family_Member.InsertOnSubmit(newfamilymember);
                        db.SubmitChanges();
                        Response.Write("<script>alert('插入数据成功！')</script>");
                    }
                }
                else
                {
                    Response.Write("<script>alert('两次密码不一致，请重新输入！')</script>");
                    //Response.Redirect("register.aspx");
                    TBpassword.Text = " ";
                    TBpassw.Text = " ";
                    TBmember_message.Text = " ";
                    TBrealname.Text = " ";
                }
            }
            else
            {
               Response.Write("<script>alert('真实姓名或用户名不能为空，请重新输入！')</script>");
            }
        }
        catch
        {
            Response.Write("<script>alert('注册失败！请重新注册')</script>");
        }
        
    }

Answer 1

自己跟踪下看看吧 要想别人能帮你 最好是整个项目一起发出来 
不然你没dal曾代码  也帮不上你

Answer 2

 Login user1 = db.Login.Where(u => u.User_Name == usernm).First();在此处打一断点ps:推荐使用firstordefault() 

Answer 3

if (user1 != null)
此处写得不对，任何一个非空值都会去执行if的下一条语句，而不会跳到else了
楼主试一下什么都不输入时会是什么情况

Answer 4

哎呀 用的还是LinQ呢这个问题不会调试啊!

Answer 5

LZ记住，你这里的User1不为空的，所以你这样写的条件不对哟

Answer 6

 //Login user1 = db.Login.Where(u => u.User_Name == usernm).First();
 Login user1 = db.Login.Where(u => u.User_Name == usernm).DefaultIfEmpty().First();  //if (user1 != null)
 if (user1.Count()>0)  

Answer 7

问题找到啦，谢谢各位！只要把插入数据库的代码放到catch中就行啦