How to check whether user name and password exists in sql in c#

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Hai,

I am having username textbox and password trxt box in c# web application.I am having a sql table "Login" which contains username and password.How to validate whether username or password exists in SQL table.

Thanks in advance

Posted 10-Dec-13 23:14pm

Member 10234093

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Sampath Lokuge 11-Dec-13 5:23am

Are you using any encryption for the password when it stores into db ?

Member 10234093 11-Dec-13 5:25am

yes.

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OriginalGriff · Answer 1 · 2013-12-10T23:22:00

Start by looking at this: Password Storage: How to do it.[^] - it doesn't cover storing or retrieving the data from teh dtabase, but that is the trivial bit:

C#

using (SqlConnection con = new SqlConnection(strConnect))
    {
    con.Open();
    using (SqlCommand cmd = new SqlCommand("SELECT password FROM myTable WHERE username=@UN", con))
        {
        cmd.Parameters.AddWithValue("@UN", txtUserName.Text);
        using (SqlDataReader reader = cmd.ExecuteReader())
            {
            if (reader.Read())
                {
                byte[] psw = (byte[])reader["password"];
                ...Check as in the Tip
                }
            }
        }
    }

Snehasish_Nandy · Answer 2 · 2013-12-10T23:27:00

Solution 2

You can check this also(off course apart from the answer Griff already gave)

checking-if-username-already-exists-within-the-databasae[^]

Posted 10-Dec-13 23:27pm

Snehasish_Nandy

Nelek · Answer 3 · 2013-12-10T23:28:00

Solution 3

How about doing a query? You can do a SELECT combined with WHERE and see what it returns, if there is data, both exists, if not... they are not in the table

http://www.w3schools.com/sql/sql_where.asp[^]

Posted 10-Dec-13 23:28pm

Nelek

Karthik_Mahalingam · Answer 4 · 2013-12-10T23:44:00

Hi
Try this simple code ..

C#

string usename  = txtusername.Text;
            string password = txtpassword.Text;


              SqlDataAdapter sqlAdapter;
            SqlCommand sqlCmd = new SqlCommand ();
            SqlConnection objConn = new SqlConnection ();
           
            objConn.ConnectionString = "your connection string";
            DataTable tbl = new DataTable();

            try
            {
                objConn.Open();
                sqlCmd.Connection = objConn;
                sqlCmd.CommandTimeout = 30;
                sqlCmd.CommandText =
                    string.Format("select count(*) as count from Login where username ='{0}' and password = '{1}' ", usename,password);

                sqlAdapter = new SqlDataAdapter(sqlCmd);
                sqlAdapter.Fill(tbl);
                sqlCmd.Dispose();

                if ( tbl != null && tbl.Rows.Count >0)
                {
                    lbl.Text = "successfull login";
                }
                else
                    lbl.Text = "Invalid Credentials";

ketan italiya · Answer 5 · 2013-12-11T01:32:00

using linq to sql try with this,

C#

protected void btnLogin_Click(object sender, EventArgs e)
      {
          EventManagerDataContext db = new EventManagerDataContext();

          var result = (from row in db.EMR_CLIENTs
                        where row.Name == txtUserName.Value.ToString() && row.Password == txtPassword.Value.ToString()
                        select row).ToList();

          if (result.Count() != 0)
          {
              Session["clientname"] = txtUserName.Value;
              Response.Redirect("DefaultClient.aspx");


          }
          else
          {
              lblMsg.Text = "Invalid username or password";
              this.lblMsg.ForeColor = Color.Red;
          }
      }

How to check whether user name and password exists in sql in c#

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