Index out of range, error - asp.net

Question

my code sometimes throw error but sometimes not.
Error:
Index out of range.
code:
protected void btnGenerateReport_Click(object sender, EventArgs e)
{
GridViewSmsComplaints.DataBind();
dtRoom.Columns.Add(new DataColumn("ID", typeof(string)));
dtRoom.Columns.Add(new DataColumn("RecievingDate", typeof(string)));
dtRoom.Columns.Add(new DataColumn("FromMobileNo", typeof(string)));
dtRoom.Columns.Add(new DataColumn("Message", typeof(string)));
dtRoom.Columns.Add(new DataColumn("IsComplaint", typeof(short)));
for (int i = 0; i <= 5; i++)
{
int ID = Convert.ToInt32(GridViewSmsComplaints.Rows[i].Cells[0].Text);
ManageRecievedMessage mngRecMsg = new ManageRecievedMessage();
DropDownList IsValid = (DropDownList) GridViewSmsComplaints.Rows[i].FindControl("ddlValidity");
short IsComplaint;
if (IsValid.SelectedValue == "1")
{
IsComplaint= Convert.ToInt16(IsValid.SelectedValue.ToString());
mngRecMsg.UpdateSmsComplaintValidity(ID, 1);
DataRow datarw = null;
datarw = dtRoom.NewRow();
datarw[0] = GridViewSmsComplaints.Rows[i].Cells[0].Text;
datarw[1] = GridViewSmsComplaints.Rows[i].Cells[1].Text;
datarw[2] = GridViewSmsComplaints.Rows[i].Cells[2].Text;
datarw[3] = GridViewSmsComplaints.Rows[i].Cells[3].Text;
datarw[4] = IsComplaint; //Convert.ToInt16(GridViewSmsComplaints.Rows[i].Cells[4].Text);
dtRoom.Rows.Add(datarw);
}
else if(IsValid.SelectedValue != "1" )
{
IsComplaint= Convert.ToInt16(IsValid.SelectedValue.ToString());
mngRecMsg.UpdateSmsComplaintValidity(ID, IsComplaint);
}
}
GridViewSmsComplaints.DataBind();
ReportViewer1.ProcessingMode = ProcessingMode.Local;
ReportViewer1.LocalReport.ReportPath = Server.MapPath("~/Reports/Report_SmsComplaintsByDate.rdlc");
if (dtRoom.Rows.Count <= 0)
{
HiddenFieldSetMessage.Value = "NotExists";
HiddenFieldShowMessage.Value = "True";
ReportViewer1.Visible = false;
GridViewSmsComplaints.DataBind();
GridViewSmsComplaints.Visible = false;
}
else
{
ReportDataSource rpds = new ReportDataSource("DataSet1", dtRoom);
ReportViewer1.LocalReport.DataSources.Clear();
ReportViewer1.LocalReport.DataSources.Add(rpds);
ReportViewer1.Visible = true;
GridViewSmsComplaints.DataBind();
GridViewSmsComplaints.Visible = false;
}
}
at this line:
int ID = Convert.ToInt32(GridViewSmsComplaints.Rows[i].Cells[0].Text);
my gridview is displaying two rows, among whihc i have to validate whether VALID (1) or invalid (0) from dropdown but it throws error but sometimes it doesn't.
ERROR:
Index was out of range. Must be non-negative and less than the size of the collection.\r\nParameter name: index"}

Answer 1

Your grid doesn't always have at least 5 rows so trying to index into the Rows collection causes your out of bounds exception. Looks a little odd to me that you're currently exepcting exactly 5 rows but if you're getting this error it is not the case.
To avoid the error change your code to this:
for (int i = 0; i < GridViewSmsComplaints.Rows.Count; i++)
{
int ID = Convert.ToInt32(GridViewSmsComplaints.Rows[i].Cells[0].Text);
....