Hide Show Button based on GridView footer value using C# in ASP.Net

hello

I am trying hide/show button for condition if i can use with cells text footer ?

       private void SearchCustomers()
       {
           try
           { 
               string constr = ConfigurationManager.ConnectionStrings["kankonConnectionString"].ConnectionString;
               using (SqlConnection con = new SqlConnection(constr))
               {
                   using (SqlCommand cmd = new SqlCommand())
                   {
                       string sql = "SELECT * FROM Table_vacation";
                       if (!string.IsNullOrEmpty(txtSearch.Text.Trim()))
                       {
                           sql += " WHERE (idnamev LIKE '%' + @idnamev + '%')";
                           sql += " OR (idcivilv LIKE '%' + @idcivilv + '%')";
 
                           sql += " AND (datestart LIKE '%' + @datestart + '%' OR ISNULL(@datestart,'') = '') ";
                           sql += " AND (namevacation LIKE '%' + @namevacation + '%' OR ISNULL(@namevacation,'') = '') ";
 
 
 
                           if (!string.IsNullOrEmpty(txtSearch.Text.Trim()))
                           {
                               cmd.Parameters.AddWithValue("@idnamev", txtSearch.Text.ToString());
                           }
 
                           if (!string.IsNullOrEmpty(txtSearch.Text.Trim()))
                           {
                               cmd.Parameters.AddWithValue("@idcivilv", txtSearch.Text.ToString());
                           }
 
 
 
                           if (int.Parse(ddlYear.SelectedItem.Value) == 0)
                           {
                               cmd.Parameters.AddWithValue("@datestart", (object)DBNull.Value);
                           }
                           else
                           {
                               cmd.Parameters.AddWithValue("@datestart", this.ddlYear.SelectedItem.Text.Trim());
                           }
 
 
                           if (int.Parse(ddlDepartment.SelectedItem.Value) == 0)
                           {
                               cmd.Parameters.AddWithValue("@namevacation", (object)DBNull.Value);
                           }
                           else
                           {
                               cmd.Parameters.AddWithValue("@namevacation", this.ddlDepartment.SelectedItem.Text.Trim());
                           }
                       }
                       cmd.CommandText = sql;
                       cmd.Connection = con;
                       using (SqlDataAdapter sda = new SqlDataAdapter(cmd))
                       {
                           DataTable dt = new DataTable();
                           sda.Fill(dt);
                           gvFiles.DataSource = dt;
                           gvFiles.DataBind();
 
 
                         gvFiles.FooterRow.Cells[13].Text = (dt.Compute("Sum(totalva)", ""), "Day").ToString();
                           gvFiles.FooterRow.Cells[14].Text = "76 Total Point Year";
 
 
                           
                           
                           gvFiles.FooterRow.Cells[15].Text = ("total point left", 76 - Convert.ToInt32(dt.Compute("Sum(totalva)", ""))).ToString();
 
 
                           int myvalue = Int32.Parse(Label_day.Text);
                           if (myvalue <= 14)
                           {
                               gvFiles.FooterRow.Cells[3].Text = ("Left", 35 - Convert.ToInt32(dt.Compute("Sum(totalva)", "")), "Day").ToString();
                               gvFiles.FooterRow.Cells[2].Text = ("Total Point 35 year");
                           }
                           else
                               if (myvalue >= 16)
                           {
                               gvFiles.FooterRow.Cells[3].Text = ("Left", 45 - Convert.ToInt32(dt.Compute("Sum(totalva)", "")), "Day").ToString();
                               gvFiles.FooterRow.Cells[2].Text = ("Total Point 45 year");
                           }
 
 
 
                           int totalhidebutton = Convert.ToInt32(gvFiles.FooterRow.Cells[15].Text);
                           if (totalhidebutton <= 0)
                           {
                               AddUsers.Enabled = false;
                           }
                           else if (totalhidebutton > 0 && totalhidebutton <= 76)
                           {
                               AddUsers.Enabled = true;
                           }
                       }
                   }
               }
           }
           catch (Exception)
           {
           }
       }