Visual Basic

Dim ds As New DataSet<br />
          Dim dt As DataTable<br />
          Dim dr As DataRow<br />
          Dim username As String = Me.txtUserName.Text<br />
          Dim password As String = Me.txtPassword.Text<br />
          Dim strSql As String = "SELECT * FROM users where username='" + username + "' and password='" + password + "'"<br />
          Dim oleConn As New OleDb.OleDbConnection("provider=microsoft.jet.oledb.4.0;Data Source=data\persedkont.mdb")<br />
          Dim oleDa As New OleDb.OleDbDataAdapter(strSql, oleConn)<br />
          oleDa.Fill(ds)<br />
          dt = ds.Tables(0)<br />
          If (dt.Rows.Count = 0) Then<br />
              MessageBox.Show(username + " does not exists!", "Login Fail", MessageBoxButtons.OK, MessageBoxIcon.Error)<br />
          Else<br />
              dr = dt.Rows(0)<br />
              Dim pass As String = dr(2).ToString<br />
              Dim userId As String = dr(1).ToString<br />
              If (dt.Rows.Count = 0) And password <> pass Then<br />
                  MessageBox.Show("Password does not match with username.", "Login Fail", MessageBoxButtons.OK, MessageBoxIcon.Error)<br />
                  Me.clearForm()<br />
              Else<br />
                  If password = pass Then<br />
                      Me.clearForm()<br />
                      Me.Close()<br />
                  End If<br />
              End If<br />
          End If<br />
          'MessageBox.Show(strSql)<br />
          Try<br />
          Catch ex As Exception<br />
              MessageBox.Show("Wrong UserId or Password")<br />
          End Try