Вывод записей в DataGridView в зависимости от выбранных значений комбобоксов

private void Form2_Load(object sender, EventArgs e)
        {
            ds = new DataSet();
            con = new SqlConnection("Data Source=.\\SQLEXPRESS;AttachDbFilename=C:\\Users\\Elena\\Desktop\\DB1.mdf;Integrated Security=True;Connect Timeout=30;User Instance=True");
 
            con.Open();
 
            //Адаптер для Operation
            SqlCommand oper_cmd = new SqlCommand("SELECT ID_operation, Operation_date, ID_operation_type, ID_operation_kind, ID_risk_degree, ID_patient  FROM dbo.Operation", con);
            oper_adapter = new SqlDataAdapter(oper_cmd);
 
            SqlCommandBuilder operbuilder;
            operbuilder = new SqlCommandBuilder(oper_adapter);
 
            //Адаптер для Patient_condition_index
            SqlCommand index_cmd = new SqlCommand("SELECT Patient_condition_index.ID_index, Patient_condition_index.Name, Patient_condition_index.ID_unit,  Patient_condition_index.Name, Patient_condition_index.Norm_value_upper, Patient_condition_index.Norm_value_lower, (RTRIM(Patient_condition_index.Name)+', '+RTRIM(Patient_index_unit.Name)) AS Full_name FROM dbo.Patient_condition_index, dbo.Patient_index_unit WHERE Patient_condition_index.ID_unit=Patient_index_unit.ID_unit ", con);
            index_adapter = new SqlDataAdapter(index_cmd);
 
            SqlCommandBuilder indexbuilder;
            indexbuilder = new SqlCommandBuilder(index_adapter);
 
 
            try
            {
                con.Open();
                DataTable dt1 = new DataTable();
                oper_adapter.Fill(dt1);
                comboBox1.DataSource = dt1;
                comboBox1.DisplayMember = "ID_operation";
                comboBox1.ValueMember = "ID_operation";
 
                DataTable dt2 = new DataTable();
                index_adapter.Fill(dt2);
                comboBox2.DataSource = dt2;
                comboBox2.DisplayMember = "Full_name";
                comboBox2.ValueMember = "ID_index";
            }
            catch (SqlException ex)
            {
                MessageBox.Show(ex.Message);
            }

            SqlCommand condition_cmd = new SqlCommand("SELECT ID_operation, ID_index, Index_measuring_time, Index_value FROM dbo.Operation_condition_index WHERE ID_operation = "+comboBox1.SelectedValue+ "ID_index = " +comboBox2.SelectedValue +"", con);
            condition_adapter = new SqlDataAdapter(condition_cmd);
 
            SqlCommandBuilder conditionbuilder;
            conditionbuilder = new SqlCommandBuilder(condition_adapter);
            dt = new DataTable();
            condition_adapter.Fill(dt);
            dataGridView1.DataSource = dt;

  public Form1()
        {
            InitializeComponent();
//допишите вот эти 2 строки:
            comboBox1.SelectedIndexChanged += new EventHandler(comboBox_SelectedIndexChanged);
            comboBox2.SelectedIndexChanged += new EventHandler(comboBox_SelectedIndexChanged);
        }
          private void comboBox_SelectedIndexChanged(object sender, EventArgs e)
          {
              //этот код будет вызываться всякий раз, когда будет изменятся выбранная ячейка в комбобокс1, комбобокс 2
 SqlCommand condition_cmd = new SqlCommand("SELECT ID_operation, ID_index, Index_measuring_time, Index_value FROM dbo.Operation_condition_index WHERE ID_operation = "+comboBox1.SelectedValue+ "ID_index = " +comboBox2.SelectedValue +"", con);
            condition_adapter = new SqlDataAdapter(condition_cmd);
 
            SqlCommandBuilder conditionbuilder;
            conditionbuilder = new SqlCommandBuilder(condition_adapter);
            dt = new DataTable();
            condition_adapter.Fill(dt);
            dataGridView1.DataSource = dt;
 
          }

SqlCommand condition_cmd = new SqlCommand("SELECT Index_measuring_time, Index_value FROM dbo.Operation_condition_index WHERE ID_operation = " + comboBox1.SelectedValue + " AND ID_index = " + comboBox2.SelectedValue + "", con);

combobox1.SelectedItem.ToString()

 try
            {
                con.Open();
                DataTable dt1 = new DataTable();
                oper_adapter.Fill(dt1);
                comboBox1.DataSource = dt1;
                comboBox1.DisplayMember = "ID_operation";
                comboBox1.ValueMember = "ID_operation";
 
                DataTable dt2 = new DataTable();
                index_adapter.Fill(dt2);
                comboBox2.DataSource = dt2;
                comboBox2.DisplayMember = "Full_name";
                comboBox2.ValueMember = "ID_index";
 
              }
            catch (SqlException ex)
            {
                MessageBox.Show(ex.Message);
            }

string Query="SELECT ID_operation, ID_index, Index_measuring_time, Index_value FROM dbo.Operation_condition_index WHERE ID_operation = "+comboBox1.SelectedValue+ "ID_index = " +comboBox2.SelectedValue;
MessageBox.Show(Query);

 SqlCommand condition_cmd = new SqlCommand("SELECT Index_measuring_time, Index_value FROM dbo.Operation_condition_index WHERE ID_operation ='" + comboBox1.SelectedValue + "' AND ID_index ='" + comboBox2.SelectedValue + "'", con);