title: Exception has been thrown by the target of an invocation in C#
body: <p>I am using BackGround Worker for Loading data from DB(MS Access).
  In my Form_Load i use:</p>
  
  <pre><code> bgw.RunWorkerAsync();
  </code></pre>
  
  <p>In my DoWork event I laod the data from DB</p>
  
  <pre><code>private void bgw_DoWork(object sender, DoWorkEventArgs e)
      {
  
          int iResult = OpenDB();
          if (iResult != 0)
          {
              MessageBox.Show("Error in Opening DataBase", Constants.TITLE);
              return ;
          }
          DataSet ds = GetAllUserInfo();
          e.Result = ds;
  
  
      }
  </code></pre>
  
  <p>And in My RunWorkerCompleted i assign data to DataGridView.</p>
  
  <pre><code>    private void bgw_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
      {
  
          dgUsers.Rows[0].Cells[0].Value = e.Result; 
  
  
      }
  </code></pre>
  
  <p>//Error Comes here after executing above code </p>
  
  <pre><code>[STAThread]
          static void Main()
          {
              Application.Run(new frmMain());
          }
  </code></pre>
  
  <p>Any help is appreciated.
  Thanks.</p>