Saving value in view state and populating the text box from view state

Saving value on Button Click in view state

protected void Copy_Click(object sender, EventArgs e)
    {
       foreach(HtmlTableRow row in table1.Rows)
        {
            foreach (HtmlTableCell cell in row.Cells)
            {
                Control control = cell.Controls[0];
                if (control is TextBox)
                {
                    ViewState[control.ID] = ((TextBox)control).Text;
                }
            }
        }
    }

and

Populating the text box from view state on Button Click

    protected void Paste_Click(object sender, EventArgs e)
    {

        foreach (HtmlTableRow row in table1.Rows)
        {
            foreach (HtmlTableCell cell in row.Cells)
            {
                Control control = cell.Controls[0];
                if (control is TextBox)
                {
                    string value = (string) ViewState[control.ID];
                    if(value != null)
                    {
                        ((TextBox) control).Text = value;
                    }

                }
            }
        }

    }