System Argument out of range exception in C# while adding rows to datagridview
<p>I have a code as follows:</p>

<pre><code>private void svars_MouseDoubleClick(object sender, MouseEventArgs e)
        {



            userSelection user_sel = new userSelection();
            string file = svars.SelectedItem.ToString();

            DataGridViewRow row = new DataGridViewRow();



            dataGridView1.Rows.Add(row);

            row.Cells["Local_Variables"].Value = "test";

            DataGridViewCell sysvar = new DataGridViewTextBoxCell();
            sysvar.Value = file;
            row.Cells["System_Variables"] = sysvar;

        }
</code></pre>

<p>I am getting error following error:</p>

<pre><code>An unhandled exception of type 'System.ArgumentOutOfRangeException' occurred in System.Windows.Forms.dll

Additional information: Specified argument was out of the range of valid values.
</code></pre>

<p>When I tried to debug I found that row.Index is -1. I am not sure how to fix it. Can anyone please help.</p>

<p>Thanks. </p>
