title: append new to gridcontrol devexpress
body: <p>I am trying add a new row into datagridview with the button click for learning purposes. When I click the button, it deletes the old data and add the new row. But I want to append it to the grid</p>
  
  <p>here is my form_load function which gets the data from the database and fill the grid.</p>
  
  <pre><code>private void Form1_Load(object sender, EventArgs e)
      {
          SqlConnection connection = new SqlConnection("Data Source=ARIF-BILGISAYAR;Initial Catalog=RotanetLocal;Persist Security Info=True;User ID=sa;Password=12345");
          SqlDataAdapter adapter = new SqlDataAdapter("SELECT * FROM TestTable", connection);
          DataSet sourceDataSet = new DataSet();
          adapter.Fill(sourceDataSet);
          gridControl1.DataSource = sourceDataSet.Tables[0];
  
      }
  </code></pre>
  
  <p>and here is my button event which is supposed to append a row into the grid, but it deletes the old data and inserts the new one</p>
  
  <pre><code>private void btn_update_Click(object sender, EventArgs e)
      {
          DataTable dtOperation = new DataTable();
  
          var myOriginalDataSource = (DataTable)gridControl1.DataSource;
          var dr = myOriginalDataSource.NewRow();
          dr["id"] = 1;
          dr["name"] = "Gelen Havale";
          dr["lname"] = "Gelen Havale";
          dtOperation.Rows.Add(dr);
  
          gridControl1.Refresh();
      }
  </code></pre>
  
  <p>my btn_update_click function is now trying to create a row and append it to the old data. but it now crashes. It says taht this row belongs to another table. how can I fix that?</p>