MySQL Exception in asp.net

Question

I tried a login page in visual studio 2017 asp.net c# web application using MySQL and it shows the following error:

Line 33:queryStr = "SELECT * FROM webapp.userregistration WHERE username='" + usernameTextBox.Text+ "'AND password='" + passwordTextBox.Text; Line 34: cmd = new MySql.Data.MySqlClient.MySqlCommand(queryStr,conn); Line 35:reader = cmd.ExecuteReader(); Line 36: Line 37: name = "";

Source File: C:\Users\HOME\source\repos\WebPage\WebPage\default.aspx.cs Line: 35

Stack Trace:

[MySqlException (0x80004005): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax at line 1]
MySql.Data.MySqlClient.MySqlStream.ReadPacket() +309
MySql.Data.MySqlClient.NativeDriver.GetResult(Int32& affectedRow, Int64& insertedId) +67
MySql.Data.MySqlClient.Driver.GetResult(Int32 statementId, Int32& affectedRows, Int64& insertedId) +17
MySql.Data.MySqlClient.Driver.NextResult(Int32 statementId, Boolean force) +110 MySql.Data.MySqlClient.MySqlDataReader.NextResult() +875 MySql.Data.MySqlClient.MySqlCommand.ExecuteReader(CommandBehavior behavior) +1688 MySql.Data.MySqlClient.MySqlCommand.ExecuteReader() +6 WebPage._default.Submit_Click(Object sender, EventArgs e) in C:\Users\HOME\source\repos\WebPage\WebPage\default.aspx.cs:35
System.Web.UI.WebControls.Button.OnClick(EventArgs e) +9782450
System.Web.UI.WebControls.Button.RaisePostBackEvent(String eventArgument) +204
System.Web.UI.WebControls.Button.System.Web.UI.IPostBackEventHandler.RaisePostBackEvent(String eventArgument) +12
System.Web.UI.Page.RaisePostBackEvent(IPostBackEventHandler sourceControl, String eventArgument) +15
System.Web.UI.Page.RaisePostBackEvent(NameValueCollection postData) +35 System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +1639

Code:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System;
using System.Data;

using MySql.Data;
using MySql.Data.MySqlClient;

namespace WebPage
{
    public partial class _default : System.Web.UI.Page
    {
        MySql.Data.MySqlClient.MySqlConnection conn;
        MySql.Data.MySqlClient.MySqlCommand cmd;
        MySql.Data.MySqlClient.MySqlDataReader reader;
        String name;
        protected void Page_Load(object sender, EventArgs e)
        {
            DoSQLQuery();
        }

        protected void Submit_Click(object sender, EventArgs e)
        {

            String connString = System.Configuration.ConfigurationManager.ConnectionStrings["WebAppConnString"].ToString();
            conn = new MySql.Data.MySqlClient.MySqlConnection(connString);
            conn.Open();
            String queryStr = "";
             queryStr = "SELECT * FROM webapp.userregistration WHERE username='" + usernameTextBox.Text+ "'AND password='" + passwordTextBox.Text;
            cmd = new MySql.Data.MySqlClient.MySqlCommand(queryStr,conn);
            reader = cmd.ExecuteReader();

            name = "";
            while (reader.HasRows && reader.Read())
            {

                {
                    name = reader.GetString(reader.GetOrdinal("username")) + " " + reader.GetString(reader.GetOrdinal("password"));
                }

                //if the data matches the rows (username, password), then you enter to the page
                if (reader.HasRows)
                {
                    Session["uname"] = name;

                    Response.BufferOutput = true;
                    Response.Redirect("login.aspx", false);

                }
                else
                {
                    passwordTextBox.Text = "invalid user";

                }
            }

            reader.Close();
            conn.Close();
        }


        private void DoSQLQuery()
        {
            try
            {

            }
            catch (Exception e)
            {
                passwordTextBox.Text = e.ToString();
            }
        }
    }
}

go.. go.. · Accepted Answer · 2018-10-03T07:55:47

string on the query side have the error and dangerous at the same time look here

your query output

SELECT * FROM webapp.userregistration WHERE username='admin'AND password='12345

last char not exist '

cmd = new MySql.Data.MySqlClient.MySqlCommand("SELECT * FROM webapp.userregistration WHERE username = @name  and password=@pas", conn);

cmd.Parameters.AddWithValue("@name", usernameTextBox.Text);
cmd.Parameters.AddWithValue("@pas", passwordTextBox.Text);

MySQL Exception in asp.net

1 Answers