Object reference not set to instance of an object

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Hello everyone,

in my web application,i am trying to bind data to data table and then data table to gridview. Code for the same is as follows.

C#

SqlCommand cmdd1 = new SqlCommand("insert into leave_rec values('" + name + "','" + date1.Text + "','" + type1 + "','" + type + "')", conn1);
cmdd1.ExecuteNonQuery();
SqlCommand cmdd2 = new SqlCommand("select date,leave,ltype from leave_rec where date='" + date1.Text + "'and name='" + name + "'", conn1);
SqlDataAdapter da = new SqlDataAdapter(cmdd2);
Session["dt"]=null;
DataTable dtable = (DataTable)Session["dt"];
string dat = date1.Text;
string hf = type1;
string lt = type;
dtable.Rows.Add(new object[] { dat,hf,lt });
dtable.AcceptChanges();
GridView1.DataSource = dtable;
GridView1.DataBind();
Session["dt"] = dtable;

In above code,i am getting error on the highlighted line that Object reference not set to instance of an object. I kindly request you all to help me in this regard.

Posted 28-Feb-13 0:07am

Thanks7872

Updated 28-Feb-13 0:10am

Orcun Iyigun

v2

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Comments

Orcun Iyigun 28-Feb-13 6:15am

Why would you need to do this:
<pre lang="c#">Session["dt"]=null;
DataTable dtable = (DataTable)Session["dt"];</pre>
instead of creating a new instance?

2 solutions

Solution 2

Try below...

You need to declare datarow object before using it..

C#

DataRow dr = null;


DataTable dtable = new DataTable();
dr = dtable.NewRow();

hope it helps you..

Posted 28-Feb-13 1:11am

vinodkumarnie

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**Orcun Iyigun** · Accepted Answer · 2013-02-28T00:13:00

Solution 1

Please try

C#

DataColumn col1 = new DataColumn("date");
DataColumn col2 = new DataColumn("leave");
DataColumn col3 = new DataColumn("lttype");
col1.DataType = System.Type.GetType("System.String");
col2.DataType = System.Type.GetType("System.String");
col3.DataType = System.Type.GetType("System.String");
dtable.Columns.Add(col1);
dtable.Columns.Add(col2);
dtable.Columns.Add(col3);
DataRow dr = dtable.NewRow();
dr["date"] = dat;
dr["leave"] = hf;
dr["lttype"] = lt;
dtable.Rows.Add(dr);

Good luck,
OI

Posted 28-Feb-13 0:13am

Orcun Iyigun

Updated 28-Feb-13 0:53am

v2

Comments

Thanks7872 28-Feb-13 6:23am

thanks for your quick reply.i have modified code the way you suggested but it now gives the same error at first line DATAROW DR=DTABLE.NEWROW(); .........?can you help me out?

Orcun Iyigun 28-Feb-13 6:39am

DataTable dtable = new DataTable(); ??? as I asked earlier which you ignored. I am again asking have you created a new instance?

Thanks7872 28-Feb-13 6:43am

due to some technical fault i saw that comment now.my bad.well,i havent created instance and i modified code like this
SqlDataAdapter da = new SqlDataAdapter(cmdd2);

DataTable dtable = new DataTable();
DataRow dd = dtable.NewRow();
dd["date"] = date1.Text;
dd["leave"] = type1;
dd["ltype"] = type;
dtable.Rows.Add(dd);
that means,i have removed session["dt"]=null and directly defined new datatable....
can you suggest me creating instance?ERROR: colomn 'date' does not belong to table

Orcun Iyigun 28-Feb-13 6:53am

check my solution again

Thanks7872 28-Feb-13 7:16am

it works like a charm.!!!!! thanks for your great support....thanks alot.