Question

我想使用条件创建一个用户尝试计数。我如何使用条件以及在下面的代码中放置位置的方式执行这种逻辑。示例：如果用户尝试使用错误的用户输入登录3次并通过，则他将收到一条消息，提示您已经达到登录尝试

#include <bits/stdc++.h>
using namespace std;
int main()
{
    int n=3;
    int a[10]={ -500, 2147483647, 2147483647};

    int t = upper_bound(a,a+n,2147483647)-a;
    int k = lower_bound(a,a+n,2147483647+1)-a;
    cout << "upper_bound: " << t << "  " << a[t]<<endl;
    cout << "lower_bound: " << k << "  " << a[k]<<endl;


    return 0;
}

Answer 1

您已经在使用SqlDataReader.Read()，一个简单的else可以处理没有结果返回的情况。您已经在使用SqlDataReader.Read()，一个简单的else可以处理没有结果返回的情况。

int failAttempt  = 0;

private void btn_login_Click(object sender, EventArgs e)
{

    // Step 1: Check if inputs are valid
    if (string.IsNullOrEmpty(txt_username.Text) || string.IsNullOrEmpty(txt_password.Text))
    {
        MetroMessageBox.Show(this, "Please input the Required Fields", "System Message:", MessageBoxButtons.OK, MessageBoxIcon.Exclamation);
        return;
    }


    // Step 2: Check if there is one user with this password/login
    var obj = new Usercontrols.SIMSMain();
    obj.Dock = DockStyle.Fill;

    conn.Open();
    SqlCommand selectCommand = new SqlCommand("Select * from admin_access where Username=@admin AND Password=@eyelab",conn);
    selectCommand.Parameters.AddWithValue("@admin", txt_username.Text);
    selectCommand.Parameters.AddWithValue("@eyelab", txt_password.Text);
    SqlDataReader dataReader = selectCommand.ExecuteReader();

    int numberMatch=0;

    while(dataReader.Read()){
        numberMatch++;
    }
    conn.Close();


    // Step 3: Fail Handle

    if(numberMatch==1){ // Success
        failAttempt  = 0;

        MetroMessageBox.Show(this, "Login Successful", "System Message:", MessageBoxButtons.OK, MessageBoxIcon.Information);
        this.Hide();
        this.Parent.Controls.Add(obj);
    }
    else { // Fail 0 or more than one
        failAttempt ++;

        if (failAttempt == 3)
        {
            MetroMessageBox.Show(this, "Super Attempt", "System Message:", MessageBoxButtons.OK, MessageBoxIcon.Information);
        }
        else
        {
            MetroMessageBox.Show(this, "Invalid Username/Password", "System Message:", MessageBoxButtons.OK, MessageBoxIcon.Stop);
        }
    }

Answer 2

在这里修改代码，以处理3次以上的尝试

Timer loginAttempsTimeOut;
Dictionary<string, int> loginAttempsPerUser = new Dictionary<string,int>();
Dictionary<string, DateTime> loginAttemptsViolated = new Dictionary<string, DateTime>();
int TimeOutInMinutes = 15;

private void SetTimer()
{
    loginAttempsTimeOut = new Timer();
    loginAttempsTimeOut.Interval = 1000 * 60; // check timeout every 1 mins
    loginAttempsTimeOut.Enalbed = true;
    loginAttempsTimeOut.Tick += LoginAttempsTimeOut_Tick;
}

// set a timer, and if login timeout for each user is elapsed,
// allow user to try login again
private void LoginAttempsTimeOut_Tick(object sender, EventArgs e)
{
    foreach(var user in loginAttemptsViolated.Keys)
    {
        loginAttemptsViolated.TryGetValue(user, out var date);
        TimeSpan span = DateTime.Now.Subtract(date);
        if(span.TotalMinutes > TimeOutInMinutes)
        {
            loginAttempsPerUser[user] = 0;
            loginAttemptsViolated.Remove(user);
            loginAttempsPerUser.Remove(user); 
        }
    }
}

private void btn_login_Click(object sender, EventArgs e)
{
        var obj = new Usercontrols.SIMSMain();
        obj.Dock = DockStyle.Fill;

        conn.Open();
        SqlCommand selectCommand = new SqlCommand("Select * from admin_access where Username=@admin AND Password=@eyelab", conn);
        selectCommand.Parameters.AddWithValue("@admin", txt_username.Text);
        selectCommand.Parameters.AddWithValue("@eyelab", txt_password.Text);
        SqlDataReader dataReader;
        dataReader = selectCommand.ExecuteReader();
        var count = 0;

        while (dataReader.Read())
        {
            count = count + 1;
        }
        if(loginAttemptsViolated.ContainsKey(txt_username.Text))
        {
           MetroMessageBox.Show("Login attempts is more than 3.");
        }
        else if (string.IsNullOrEmpty(txt_username.Text) || string.IsNullOrEmpty(txt_password.Text))
        {
            MetroMessageBox.Show(this, "Please input the Required Fields", "System Message:", MessageBoxButtons.OK, MessageBoxIcon.Exclamation);
        }
        else
        {
            if (count == 1)
            {
                MetroMessageBox.Show(this, "Login Successful", "System Message:", MessageBoxButtons.OK, MessageBoxIcon.Information);
                this.Hide();
                this.Parent.Controls.Add(obj);
            }
            else if (count == 3)
            {
                count++;
                MetroMessageBox.Show(this, "Super Attempt", "System Message:", MessageBoxButtons.OK, MessageBoxIcon.Information);
            }
            else
            {
                //if user cannot login, increase login attempts
                if(!loginAttempsPerUser.ContainsKey(txt_username.Text))
                   loginAttempsPerUser.Add(txt_username.Text, 1);

                loginAttempsPerUser[txt_username.Text]++;
                if(loginAttempsPerUser[txt_username.Text] > 2)
                {
                    // if login attempts > 2 set a 15 min timeout till user 
                    // cant login
                    if(!loginAttemptsViolated.ContainsKey(txt_username.Text))
                       loginAttemptsViolated.Add(txt_username.Text, DateTime.Now);
                }
                MetroMessageBox.Show(this, "Invalid Username/Password", "System Message:", MessageBoxButtons.OK, MessageBoxIcon.Stop);
            }
        }
        conn.Close();
    }

}

也存在超时，因为如果用户违反了登录次数，则必须稍后再给他/她另一个机会（例如，在15分钟后）。

Answer 3

您需要将计数变量声明为全局变量。

    int count = 1;
    private void btn_login_Click(object sender, EventArgs e)
    {
        var obj = new Usercontrols.SIMSMain();
        obj.Dock = DockStyle.Fill;

        conn.Open();
        SqlCommand selectCommand = new SqlCommand("Select * from admin_access where Username=@admin AND Password=@eyelab", conn);
        selectCommand.Parameters.AddWithValue("@admin", txt_username.Text);
        selectCommand.Parameters.AddWithValue("@eyelab", txt_password.Text);
        SqlDataReader dataReader;
        dataReader = selectCommand.ExecuteReader();
        var counter = 0; //to check if there is data
        while (dataReader.Read())
        {
            counter++;
        }
        if (string.IsNullOrEmpty(txt_username.Text) || string.IsNullOrEmpty(txt_password.Text))
        {
            MetroMessageBox.Show(this, "Please input the Required Fields", "System Message:", MessageBoxButtons.OK, MessageBoxIcon.Exclamation);
        }
        else
        {
            if (counter == 1)
            {
                MetroMessageBox.Show(this, "Login Successful", "System Message:", MessageBoxButtons.OK, MessageBoxIcon.Information);
                this.Hide();
                this.Parent.Controls.Add(obj);
            }
            else if (count == 3)
            {
                count++;
                MetroMessageBox.Show(this, "Super Attempt", "System Message:", MessageBoxButtons.OK, MessageBoxIcon.Information);
            }
            else
            {
                count++;
                MetroMessageBox.Show(this, "Invalid Username/Password", "System Message:", MessageBoxButtons.OK, MessageBoxIcon.Stop);
            }
        }
        conn.Close();
    }

Answer 4

您必须声明一个静态计数器，该计数器随着每次用户登录单击而增加。如果同一用户正在尝试并且计数器为3，则显示消息，例如“您已超出限制”。下面是修改后的代码。

          private static int loginCounter;
          private static string UserName;

          private void btn_login_Click(object sender, EventArgs e)
        {
                var obj = new Usercontrols.SIMSMain();
                obj.Dock = DockStyle.Fill;

                conn.Open();
                SqlCommand selectCommand = new SqlCommand("Select * from admin_access where Username=@admin AND Password=@eyelab",conn);
                selectCommand.Parameters.AddWithValue("@admin", txt_username.Text);
                selectCommand.Parameters.AddWithValue("@eyelab", txt_password.Text);
                SqlDataReader dataReader;   
                dataReader = selectCommand.ExecuteReader();
                var count = 0;

                while (dataReader.Read())
                {
                    count = count + 1;
                }
            if (string.IsNullOrEmpty(txt_username.Text) || string.IsNullOrEmpty(txt_password.Text))
            {
                MetroMessageBox.Show(this, "Please input the Required Fields", "System Message:", MessageBoxButtons.OK, MessageBoxIcon.Exclamation);
            }
            else
            {
            if (count == 0 && UserName == txt_username.Text)
            {
           loginCounter += 1;
             }
            if(loginCounter  >= 3)
            {
     MetroMessageBox.Show(this, "You have exceeded maximum login attempts.", "System Message:", MessageBoxButtons.OK, MessageBoxIcon.Stop);
            }
UserName == txt_username.Text
                if (count == 1)
                {
// Here reset the login counter, since the password is right
loginCounter = 0;
UserName = "";
                    MetroMessageBox.Show(this, "Login Successful", "System Message:", MessageBoxButtons.OK, MessageBoxIcon.Information);
                    this.Hide();
                    this.Parent.Controls.Add(obj);
                }
                else if (count == 3)
                {
                    count++;
                    MetroMessageBox.Show(this, "Super Attempt", "System Message:", MessageBoxButtons.OK, MessageBoxIcon.Information);
                }
                else
                {
                    MetroMessageBox.Show(this, "Invalid Username/Password", "System Message:", MessageBoxButtons.OK, MessageBoxIcon.Stop);
                }    
            }

            conn.Close();
        }

用户尝试使用计数

4 个答案: