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25 May 2016 14:04

Joined:	17/05/2016
Level:	Bronze
Points:	23

Points:	5

Object reference not set to an instance of an object

Hello,
I had a grid view with edit item template with drop down lists and textboxes. When I am clicking "Update" button , I am getting an error "Object reference not set to an instance of an object" pointing at "UpdateRow " method. When I tried to debug I am getting null values in textboxes and dropdownlist .

Code behind:
protected void grdSupList_RowUpdating(object sender, GridViewUpdateEventArgs e)
{
string id = grdSupList.DataKeys[e.RowIndex].Value.ToString();
TextBox txt_SupId = (TextBox)grdSupList.FooterRow.FindControl("txtSupId");
TextBox txt_SupName = (TextBox)grdSupList.FooterRow.FindControl("txtSupName");
TextBox txt_City = (TextBox)grdSupList.FooterRow.FindControl("txtCity");
TextBox txt_State = (TextBox)grdSupList.FooterRow.FindControl("txtState");
TextBox txt_Country = (TextBox)grdSupList.FooterRow.FindControl("txtCountry");
DropDownList txt_act = (DropDownList)grdSupList.FooterRow.FindControl("ddlActivity");
DropDownList txt_loc = (DropDownList)grdSupList.FooterRow.FindControl("ddlLocal");

int sqlid = Convert.ToInt32(id);
UpdateRow(sqlid, txt_SupId.Text, txt_SupName.Text, txt_City.Text, txt_State.Text, txt_Country.Text, txt_act.SelectedItem.Text, txt_loc.SelectedItem.Text);
grdSupList.EditIndex = -1;
FillGrid();
lblMsg.Text = "Record updated successfully!";
}

private void UpdateRow(int id, string SupId, string SupName, string city, string state, string country, string status, string location)
{
string connString = ConfigurationManager.ConnectionStrings["cn"].ConnectionString;

int bitstatus = 0;
if (status == "Yes")
{
bitstatus = 1;
}
else
{
bitstatus = 0;
}

string sql = String.Format("update tblTBT_Vendors set SupplierID ='" + SupId + "', SupplierName= '" + SupName + "', City='" + city + "', StateOrProvince='" + state + "', Country='" + country + "', Inactive = '" + bitstatus + "', LocalRegion='" + location + "' where ID='" + id + "' ");
using (SqlConnection conn = new SqlConnection(connString))
{
conn.Open();
using (SqlCommand cmd = new SqlCommand(sql, conn))
{
cmd.ExecuteNonQuery();
}
}
}

ASPX (344651-1-ASPX.txt)

#766169

25 May 2016 21:16

Joined:	29/05/2009
Level:	Gold
Points:	10380

Points:	1

Hi

Debug trace line by line in your code.

The issue is Object reference not set to an instance of an object

Reason
==========

1.we need instance that object.
2.your control name not correct
3.your control name C# code did not recognize.

Best trace step by step thats best way.

when you post the issue . Please attached table script with 2 records temp data then only Reply members easily find out fixed in your issue.

Name : Dotnet Developer-2015
Email Id : kumaraspcode2009@gmail.com

'Not by might nor by power, but by my Spirit,' says the LORD Almighty.

#766170

25 May 2016 21:18

Joined:	29/05/2009
Level:	Gold
Points:	10380

Points:	1

Hi
where is FillGrid method?

Step1
===========
1.Share your table script with Data

Step2:
======
2.Share Proper all code in your c#,aspx

then only easily fixed in your issue

Name : Dotnet Developer-2015
Email Id : kumaraspcode2009@gmail.com

'Not by might nor by power, but by my Spirit,' says the LORD Almighty.

#766173

25 May 2016 21:50

Joined:	13/06/2007
Level:	Gold
Points:	21327

Points:	4

Object reference error is thrown by compiler when there is NULL object you are trying to access it. Now as per your code, it looks textboxes and dropdownlist are null, first you need to use 'GridView1_RowUpdating' event
see below sample, here I have access controls from gridviewRow and update them


protected void GridView1_RowUpdating(object sender, GridViewUpdateEventArgs e)
    {
        GridViewRow row = (GridViewRow)GridView1.Rows[e.RowIndex];
        int id = Int32.Parse(GridView1.DataKeys[e.RowIndex].Value.ToString());
        string tname = ((TextBox)row.Cells[0].Controls[0]).Text;
        string tques = ((TextBox)row.Cells[1].Controls[0]).Text;
        MySqlCommand cmd = new MySqlCommand("update exam set name1=@name,ques=@ques where id = @id", con);
        cmd.Parameters.Add("@id", MySqlDbType.Int16).Value = id;
        cmd.Parameters.Add("@name", MySqlDbType.VarChar, 30).Value = tname.Text.Trim();
        cmd.Parameters.Add("@ques", MySqlDbType.VarChar, 40).Value = tques.Text.Trim();
        con.Open();
        cmd.ExecuteNonQuery();
        GridView1.EditIndex = -1;
        bind();
}

Thanks
Koolprasd2003
Editor, DotNetSpider MVM
Microsoft MVP 2014 [ASP.NET/IIS]

#766177

25 May 2016 22:47

Joined:	03/05/2013
Level:	Gold
Points:	15822

Points:	4

Hi,

If you are trying to access null object and perform action against that null object that time you will get this type of error, for example you are trying to assign some control value, but control is not able to find that means control id is null you are trying to use that control value that time you will get this type of error, in the same way many places we will get this type of issue, but the reason behind this is accessing null object. As you said textbox and dropdown values are null, may be because of that you will get this error, I suggest you to recheck why it is null? then you will get the solution for this.

--------------------------------------------------------------------------------
Give respect to your work, Instead of trying to impress your boss.

N@veen
Blog : http://naveens-dotnet.blogspot.in/

#766179

26 May 2016 00:43

Joined:	05/06/2009
Level:	Gold
Points:	10245

Points:	3

I am sure this issue is because some of the value coming as null values. It is trying to assing the null value into the typed value.

By using the debugger you can find the exception line. If you find the exact line you can easily identify the issue value

I am suspecting any one of the following value may be null
int id, string SupId, string SupName, string city, string state, string country, string status, string location

By Nathan
Direction is important than speed

#766194

26 May 2016 05:08

Joined:	17/05/2016
Level:	Bronze
Points:	23

Points:	1

Hi Everyone,

Thanks for responding. It is my mistake , I want to update textboxes in rows but in code I written to update the textboxes in footer row , problem is solved.

I will make sure to post my data table and entire code while posting a question next time.

Object reference not set to an instance of an object

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