получить данные из БД SQL server по значению textbox

private void button1_Click(object sender, EventArgs e)
        {
            SqlConnection scn = new SqlConnection(" data source = ACY314_05_PGTKK;initial catalog = Test_db;integrated security = true ");
            SqlDataAdapter sda = new SqlDataAdapter();
            sda.InsertCommand = new SqlCommand("insert into gaz values(@lch, @city, @street, @dom, @kv)", scn);
            sda.InsertCommand.Parameters.Add("@lch", SqlDbType.VarChar).Value = textBox1.Text;
            sda.InsertCommand.Parameters.Add("@city", SqlDbType.VarChar).Value=textBox2.Text;
            sda.InsertCommand.Parameters.Add("@street", SqlDbType.VarChar).Value=textBox3.Text;
            sda.InsertCommand.Parameters.Add("@dom", SqlDbType.VarChar).Value=textBox4.Text;
            sda.InsertCommand.Parameters.Add("@kv", SqlDbType.VarChar).Value = textBox5.Text;
            scn.Open();
            sda.InsertCommand.ExecuteNonQuery();
            scn.Close();
 
        }

SqlConnection scn = new SqlConnection(" data source=ACY314_05_PGTKK;" +
            "initial catalog = Test_db;integrated security = true ");
            SqlDataAdapter sda = new SqlDataAdapter();
            sda.InsertCommand = new SqlCommand("SELECT * FROM gaz WHERE lch =",textBox1.Text);

DataSet dataSet = new DataSet();
    using (SqlConnection scn = new SqlConnection(" data source = ACY314_05_PGTKK;initial catalog = Test_db;integrated security = true "))
    {
        using (SqlDataAdapter sda = new SqlDataAdapter())
        {
            sda.SelectCommand.Connection = scn;
            sda.SelectCommand = new SqlCommand("SELECT * FROM gaz WHERE lch = @IchValue");
            SqlParameter ichValueParameter = new SqlParameter("@IchValue", SqlDbType.VarChar);
            ichValueParameter.Value = textBox1.Text;
            sda.SelectCommand.Parameters.Add(ichValueParameter);
 
            scn.Open();
            sda.Fill(dataSet);
            scn.Close();
        }
    }

int m = *BindingSource.Find("lch", textBox*.Text);
            *BindingSource.Position = m;