如何在对象列表中搜索? [英] How to search in object list?

问题描述

我在对象列表中搜索时遇到麻烦，我想比较这些值并返回该人的信息，但是问题是，对于未找到的每条记录，它都会给我一个错误.

 Member_Login objM = 新 Member_Login();
            列表< member_login> objList = 新 List< member_login>();
            objList = objM.Get_Member_Details();

             foreach (Member_Login M  in  objList中的成员)
            {
                如果(txtUsername.Text == M.Username&& txtPassword.Text == M.Password)
                {
                    lblresult.Text = M.Member_Id.ToString();
                    会话[" ] = M.Member_Id.ToString();
                    Response.Redirect(" );
                }
                其他
                {
                    MessageBox.Show(" ， 错误！无效的帐户"，MessageBoxButtons.OK，MessageBoxIcon.Warning)；
       
                }
            } </  member_login  >  

解决方案

我认为您需要清理并重新命名变量.您似乎将Member_Login用作类，将member_login(small initials)用作该类的属性.但是，然后在您的foreach循环中将Member_Login (Capitals)用作属性.就个人而言，这就是我认为您出了点问题的地方.请参见密码存储:操作方法. [ ^ ]

您的代码逻辑错误:错误条件应仅在循环结束时发出信号.
我不是ASP专家，但以下代码可以解决问题:

foreach (Member_Login M in objList)
{
  if (txtUsername.Text == M.Username && txtPassword.Text == M.Password)
  {
    lblresult.Text = M.Member_Id.ToString();
    Session["Memid"] = M.Member_Id.ToString();
    Response.Redirect("Home.aspx");
  }
}
// ''redirect'' didn''t occur: member not found
MessageBox.Show("You are not found as a registered member", "Error!! Invalid Account", MessageBoxButtons.OK, MessageBoxIcon.Warning);

I''m having trouble searching in an object list, I want to compare the values and return that persons info, but the problem is that it gives me an error for each record not found.

Member_Login objM = new Member_Login();
            List<member_login> objList = new List<member_login>();
            objList = objM.Get_Member_Details();           

            foreach (Member_Login M in objList)
            {
                if (txtUsername.Text == M.Username && txtPassword.Text == M.Password)
                {
                    lblresult.Text = M.Member_Id.ToString();
                    Session["Memid"] = M.Member_Id.ToString();
                    Response.Redirect("Home.aspx");
                }
                else
                {
                    MessageBox.Show("You are not found as a registered member", "Error!! Invalid Account", MessageBoxButtons.OK, MessageBoxIcon.Warning);
       
                }
            }</member_login>

解决方案

I think you need to clean up and do some renaming of variables. You seem to be using Member_Login as a class and member_login(small initials) as a property of the class. But then you use Member_Login (Capitals) as the property in your foreach loop. Personally, that is where I think you are going wrong somehow.

I agree with Wayne, but would add that you should never store passwords in clear anyway. See Password Storage: How to do it.[^]

The logic of your code is wrong: the error condition should be signaled only at the end of the loop.
I''m not a ASP expert but the following code should do the trick:

foreach (Member_Login M in objList)
{
  if (txtUsername.Text == M.Username && txtPassword.Text == M.Password)
  {
    lblresult.Text = M.Member_Id.ToString();
    Session["Memid"] = M.Member_Id.ToString();
    Response.Redirect("Home.aspx");
  }
}
// ''redirect'' didn''t occur: member not found
MessageBox.Show("You are not found as a registered member", "Error!! Invalid Account", MessageBoxButtons.OK, MessageBoxIcon.Warning);

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