How to solve System.ArgumentOutOfRangeException - asp.net

Question

I have two page one MasterPage.master and default I think this error for two table[0] I am using in master page,master one poll with data table and default I am using data table for show news when remove data table in page default and run is correct with out error when use two data table I am see error
when run default.aspx this error see:
Specified argument was out of the range of valid values.
Parameter name: index
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.
Exception Details: System.ArgumentOutOfRangeException: Specified argument was out of the range of valid values.
Parameter name: index
Source Error:
Line 88: tbl.BorderWidth = 0;
Line 89: tbl.Attributes.Add("Style", "text-align:right");
Line 90: ImageButton ButtonPolls = (ImageButton)tbl.Controls[0];
Line 91: ButtonPolls.ImageUrl = "../images/poll/CastVote.jpg";
Line 92:
this code use MasterPage.master
string strSQL = "select QuestionText from TPollQuestions where Iscurrent=1 and Isarchived=0";
string cmdtext = "";
SqlConnection conn = Conn;
Pollcontrol1.CanVote = true;
if (conn.State == System.Data.ConnectionState.Closed)
conn.Open();
cmdtext = "select QuestionText from TPollQuestions where Iscurrent=1 and Isarchived=0";
cmd = new SqlCommand(cmdtext, conn);
Pollcontrol1.PollQuestion = cmd.ExecuteScalar().ToString();
conn.Close();
cmdtext =
"select optionID,PollID,OptionText,Votes from TPollOptions where pollID in(select PollID from TPollquestions where Iscurrent=1 and Isarchived=0)";
SqlDataAdapter da = new SqlDataAdapter(cmdtext, conn);
DataTable dt = new DataTable();
da.Fill(dt);
for (int i = 0; i < dt.Rows.Count; i++)
{
Pollcontrol1.AddPollAnswer(Convert.ToInt32(dt.Rows[i]["pollID"]), Convert.ToInt32(dt.Rows[i]["optionID"]), dt.Rows[i]["optionText"].ToString(), Convert.ToInt32(dt.Rows[i]["votes"]));
}
TableCell tbl = (TableCell)Pollcontrol1.Controls[0].Controls[Pollcontrol1.Controls[0].Controls.Count - 1].Controls[0];
tbl.BorderWidth = 0;
tbl.Attributes.Add("Style", "text-align:right");
ImageButton ButtonPolls = (ImageButton)tbl.Controls[0];
ButtonPolls.ImageUrl = "../images/poll/CastVote.jpg";
and this code in default.aspx
this datatable for show news when remove getdata(str) is run correct with out error
PagedDataSource pgsource = new PagedDataSource();
int findex, lindex;
DataRow dr1;
static string str = "select * from TNews where 1=1";
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
//CurrentPage = 0;
GetData(str);
}
}
DataTable GetData(string str)
{
DataTable dtable1= new DataTable();
SqlConnection Conn;
SqlCommand Cmd;
Conn = new SqlConnection(ConfigurationManager.ConnectionStrings["bakerConnectionString"].ToString());
Cmd = new SqlCommand();
Conn.Open();
Cmd.Connection = Conn;
Cmd.CommandText = str;
SqlDataAdapter dap1= new SqlDataAdapter(Cmd);
DataSet ds1 = new DataSet();
dap1.Fill(ds1, "ds1");
pgsource.DataSource = ds1.Tables[0].DefaultView;
DataBind();
return ds1.Tables[0];
}

Answer 1

Looking at the error message I would have to guess that your problem is here:
Line 90: ImageButton ButtonPolls = (ImageButton)tbl.Controls[0];
Also, I see you use the index-based retrieval of controls quite a lot which, is not desirable. Instead, use Control.FindControl method to retrieve the child controls (and, of course, check for nulls).
Let's say your ImageButton has the id _imgButton. To retrieve it from the table use:
var imgButton = tbl.FindControl("_imgButton") as ImageButton;
if(imgButton != null)
{
// your logic here...
}