Unable to retrieve value of the gridview column after making it invisible
<p>I have a gridview say gv1 . Which has 5 columns. I bind the gridview on the change of a dropdown selection. After binding I make the 4th(gv1.column[3]) and 5th(gv1.column[4])column visible false.</p>

<pre><code>gv1.Columns[3].Visible = false;
gv1.Columns[4].Visible = false;
</code></pre>

<p>I am unable to access the column value(these are id's) later.
I tried making it visible before accessing still in vain.</p>

<pre><code>{
    gv1.Columns[3].Visible = True;
    gv1.Columns[4].Visible = True;

    int id = Convert.ToInt32(row.Cells[4].Text.ToString().Trim());
}
</code></pre>

<p>I get the error at 'id' "Input string was not in a correct format."
I found ,All the column for each value is having null value.</p>
