使用executeNonquery时，表未更新

Question

我正在尝试更改用户密码。我无法更新密码:(。我收到的消息是密码已更改，而密码未更改。. 我的代码如下..如果有人可以建议我哪里出错了。我只是一个初学者...

protected void Button1_Click(object sender, EventArgs e)
{
    DatabaseLayer data = new DatabaseLayer();

    string username = Session["Authenticate"].ToString();
    string password = TextBox1.Text;
    string newpass = TextBox2.Text;
    string confirm = TextBox3.Text;
    string flag = "";

    if (newpass.ToString() == confirm.ToString())
    {
        flag = data.passwordChange(username, password, newpass);
        Literal1.Text = flag.ToString();
    }
    else
    {
        Literal1.Text = "New Password does not match the Confirm Password ";
    }
}

上面的点击事件必须更改我的密码，并且函数passwordChange如下..

public string passwordChange(string username, string password, string newPasswd)
{
    string SQLQuery = "SELECT password FROM LoginAccount WHERE username = '" + username + "'";
    string SQLQuery1 = "UPDATE LoginAccount SET password = ' " + newPasswd + " ' WHERE username = ' " + username + "'";
    SqlCommand command = new SqlCommand(SQLQuery, sqlConnection);
    SqlCommand command1 = new SqlCommand(SQLQuery1, sqlConnection);

    sqlConnection.Open();
    string sqlPassword = "";
    SqlDataReader reader;

    try
    {
        reader = command.ExecuteReader();


        if (reader.Read())
        {
            if (!reader.IsDBNull(0))
            {
                sqlPassword = reader["password"].ToString();
            }
        }
        reader.Close();

        if (sqlPassword.ToString() == password.ToString())
        {
            try
            {
                int flag = 0;
                flag = command1.ExecuteNonQuery();

                if (flag > 0)
                {
                    sqlConnection.Close();
                    return "Password Changed Successfully";
                }
                else
                {
                    sqlConnection.Close();
                    return "User Password could not be changed";
                }
            }
            catch (Exception exr)
            {
                sqlConnection.Close();
                return "Password Could Not Be Changed Please Try Again";
            }
        }
        else
        {
            sqlConnection.Close();
            return "User Password does not Match";
        }
    }
    catch (Exception exr)
    {
        sqlConnection.Close();
        return "User's Password already exists";
    }
}

我在它附近放置了一个断点

if(flag>0)

仍然显示executeNonquery不会返回更新的行值并且也在后端SQL Server 的，它没有改变， 如果有人可以纠正我，请...我应该使用其他执行命令还是其他命令？ 我正在使用 VS 2008 和 SQL Server 2005 执行此操作。

Answer 1

1：这是单引号和双引号之间的间距：（例如：'“+用户名+”'）
2）你正在乞求SQL注入。

在您的 PasswordChange 方法中尝试一下：

public string PasswordChange(string userName, string oldPass, string newPass)
{
    using(SqlConnection sqlConnection = new SqlConnection(
        ConfigurationManager.ConnectionStrings["LoginDb"].ConnectionString))
   {
    string sqlToConfirmOldPass =
      "SELECT password FROM LoginAccount WHERE username = @userName";
    string sqlToUpdatePassword =
      "UPDATE LoginAccount SET password = @newPass WHERE username = @userName";

    SqlCommand confirmOldPass = new SqlCommand(sqlToConfirmOldPass, sqlConnection);
    confirmOldPass.Parameters.AddWithValue("@userName", userName);

    SqlCommand updatePassword = new SqlCommand(sqlToUpdatePassword, sqlConnection);
    updatePassword.Parameters.AddWithValue("@newPass", newPass);
    updatePassword.Parameters.AddWithValue("@userName", userName);

    [Rest of your code goes here]
   }
}

我也没有看到您在哪里设置 SqlConnection，因此我为此添加了一行。您需要根据您的需要对其进行修改。

Answer 2

也许可以试试这个代码。

public string passwordChange(string username, string password, string newPasswd)
{
    string SQLQuery = "SELECT password FROM LoginAccount WHERE username = @username";
    string SQLQuery1 = "UPDATE LoginAccount SET password = @newPassword  WHERE username = @username";
    SqlCommand command = new SqlCommand(SQLQuery, sqlConnection);
    command.Parameters.AddWithValue("@username", username);

    SqlCommand command1 = new SqlCommand(SQLQuery1, sqlConnection);
    command1.Parameters.AddWithValue("@username", username);
    command1.Parameters.AddWithValue("@newPassword", newPasswd);

    sqlConnection.Open();
    string sqlPassword = "";
    SqlDataReader reader;

    try
    {
        reader = command.ExecuteReader();


        if (reader.Read())
        {
            if (!reader.IsDBNull(0))
            {
                sqlPassword = reader["password"].ToString();
            }
        }
        reader.Close();

        if (sqlPassword.ToString() == password.ToString())
        {
            try
            {
                int flag = 0;
                flag = command1.ExecuteNonQuery();

                if (flag > 0)
                {
                    sqlConnection.Close();
                    return "Password Changed Successfully";
                }
                else
                {
                    sqlConnection.Close();
                    return "User Password could not be changed";
                }
            }
            catch (Exception exr)
            {
                sqlConnection.Close();
                return "Password Could Not Be Changed Please Try Again";
            }
        }
        else
        {
            sqlConnection.Close();
            return "User Password does not Match";
        }
    }
    catch (Exception exr)
    {
        sqlConnection.Close();
        return "User's Password already exists";
    }
}

Answer 3

如果受影响的行数为零，请仔细检查 WHERE 子句是否确实有效。我敢打赌，如果您选择 WHERE username = '" + username + "'"，您将找不到您要查找的行。那至少是第一行我会确认的事情。