登录验证不适用于3层archuitecture [英] Login verification is not working with 3 tier archuitecture

问题描述

任何输入它登录到应用程序。



数据层：

with any inputs it is logging into application.

Data layer:

public DataSet Userlogin(Users objlogin)
       {
           SqlConnection con = new SqlConnection(ConnString);
           SqlCommand cmd = new SqlCommand("SELECT * FROM User_details WHERE [Login Id]=@loginid AND [Password]=@password", con);
           cmd.Parameters.AddWithValue("@loginid", objlogin.loginId);
           cmd.Parameters.AddWithValue("@password", objlogin.Password);

           SqlDataAdapter da = new SqlDataAdapter(cmd);
           DataSet ds = new DataSet();
           da = new SqlDataAdapter(cmd);
           da.Fill(ds);
           return ds;
           //DataTable dt = new DataTable();
           //da.Fill(dt);
           //return (dt);
       }

BLL：

BLL:

public DataSet Userlogin(Users objUser)
       {

           DataLayer objUserDAL = new DataLayer();
           try
           {

               return objUserDAL.Userlogin(objUser);
           }
           catch (Exception ex)
           {
               throw ex;
           }
       }

UI图层：

UI layer:

<pre> protected void btnlogin_Click(object sender, EventArgs e)
        {
            Users objuser = new Users();
            objuser.loginId = loginid.Text;
            objuser.Password = pwd.Text;
            DataSet ds = new DataSet();
            //DataTable dt = new DataTable();

            BAL objBAL = new BAL();
            ds= objBAL.Userlogin(objuser);

            if(ds.Tables.Count>0)
            {
                Session["User"] = loginid.Text;
                Response.Redirect("~/Transactions.aspx");
            }
            else
            {
                Response.Write("<script>alert('Invalid Credentials!')</script> ");
            }
          
        }
    }
}

我尝试了什么：



它使用单层以下代码

What I have tried:

It is working with single tier- below code

<pre>   protected void btnlogin_Click(object sender, EventArgs e)
        {
            String strConnString = ConfigurationManager.ConnectionStrings["conString"].ConnectionString;

            SqlConnection con = new SqlConnection(strConnString);

            SqlCommand cmd = new SqlCommand("SELECT * FROM User_details WHERE [Login Id]=@loginid AND [Password]=@password",con );
            cmd.Parameters.Add("@loginid", SqlDbType.VarChar).Value = loginid.Text;
            cmd.Parameters.Add("@password", SqlDbType.VarChar).Value = pwd.Text;
              
            SqlDataAdapter da = new SqlDataAdapter(cmd);

            DataTable dt = new DataTable();
            da.Fill(dt);
            if(dt.Rows.Count > 0)
            {
                Session["User"] = loginid.Text;
                Response.Redirect("Transactions.aspx");
               
            }

            else
            {
                
                Response.Write("<script>alert('Invalid Credentials!')</script> ");
               
            }
        }

推荐答案

第一步是了解代码。



无效的那个

First step is to understand the code.

The one that does not work has

if(ds.Tables.Count>0)

和工作的那个

and the one that does work has

if(dt.Rows.Count > 0)

您需要检查表是否存在，然后检查行是否存在。

You need to check if tables exist and THEN also check if Rows exist.

DataSet 由 DataTables 组成，因此您需要指定如下表：

DataSet is composed of DataTables so you need to specify the table like this:

ds.Tables["TableName"].Count > 0

或使用这样的索引：

or using index like this:

ds.Tables[0].Count > 0

虽然有效，但我仍然建议您使用 DataTable 而不是 DataSet ，因为您只处理一个数据库表。另外，养成使用 SqlConnection ， SqlCommand <等资源的对象的习惯在using语句中使用/ code>和 SqlDataAdapter ，以确保在使用对象后对象将被正确处理和关闭。这是一个简单的例子：





While what works, I would still recommend you to DataTable instead of DataSet since you are only dealing with one database table. Also, make it a habit to put objects that eat resources such as SqlConnection, SqlCommand and SqlDataAdapter within a using statement to ensure that objects will be properly disposed and closed after they are used. Here's a quick example:

public DataTable Userlogin(Users objlogin){
       DataTable dt = new DataTable();
	   string sqlStatement = "SELECT * FROM User_details WHERE [Login Id]=@loginid AND [Password]=@password";
   
        	using(SqlConnection connection = new SqlConnection(GetConnectionString())){
           		using(SqlCommand cmd = new SqlCommand(sqlStatement ,connection)){
               	 	cmd.CommandType = CommandType.Text;
       	            cmd.Parameters.AddWithValue("@loginid", objlogin.loginId);
           			cmd.Parameters.AddWithValue("@password", objlogin.Password);
					using(SqlDataAdapter da = new SqlDataAdapter(cmd)){
						da.Fill(dt);
					}
        		}
        }
	return 	dt;	
}

然后在您的业务层中，您还需要返回一个DataTable，这样您就可以在你的UI层：

Then in your Business layer, you would need to return a DataTable too so you can do something like this in your UI layer:

BAL objBAL = new BAL();
            DataTable dt = objBAL.Userlogin(objuser);

            if(dt.Rows.Count > 0)
            {
                Session["User"] = loginid.Text;
                Response.Redirect("~/Transactions.aspx");
            }
            else
            {
                Response.Write("<script>alert('Invalid Credentials!')</script> ");
            }

注意我们现在正在使用 dt.Rows.Count 检查您的查询是否返回任何数据。

Note that we're now using dt.Rows.Count to check if your query returns any data.

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