error persisting while inserting a record in database"object reference not set to an instance of an object"

Question

1.00/5 (2 votes)

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C#

        DialogResult dh = MessageBox.Show("DO YOU WANT TO INSERT ?", "CONFIRM YOUR INSERT", System.Windows.Forms.MessageBoxButtons.YesNo);
        if (dh != DialogResult.No)
        {
            SqlCommand cmd = new SqlCommand("exec insertcatego @description,@quality,@quantity,@priceUnit,@vat,@totalprice", con);
            cmd.Parameters.AddWithValue("@description", txtDesc.Text);
            cmd.Parameters.AddWithValue("@quality", comboBoxQuality.SelectedValue.ToString());
            cmd.Parameters.AddWithValue("@quantity", txtQant.Text);
            cmd.Parameters.AddWithValue("@priceUnit", txtpUnt.Text);
            cmd.Parameters.AddWithValue("@vat", txtVat.Text);
            cmd.Parameters.AddWithValue("@totalprice", txtTotP.Text);
            con.Close();
            con.Open();
            cmd.ExecuteNonQuery();
            frmcategory_Load(sender, e);
            MessageBox.Show("SUCCESSFULL INSERT");
        }
    }
    catch (Exception a)
    {
        MessageBox.Show(a.Message.ToString());
    }
}

Posted 1-Aug-12 2:43am

Gilbertinino

Updated 1-Aug-12 5:19am

v5

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Comments

Santhosh Kumar Jayaraman 1-Aug-12 8:48am

At which line You are gettting error? Check the object which is null in the line

Malli_S 1-Aug-12 9:00am

Where exactly you're getting the error? Find out the line where the error is thrown, and check for that object. Check whether the objects are initialized/created.

[no name] 1-Aug-12 9:08am

You need to debug your own code. This is just a code dump.

Vani Kulkarni 1-Aug-12 9:14am

Where are you getting the error? Mark the line.

Gilbertinino 1-Aug-12 10:42am

try
{
DialogResult dh = MessageBox.Show("DO YOU WANT TO INSERT ?", "CONFIRM YOUR INSERT", System.Windows.Forms.MessageBoxButtons.YesNo);
if (dh != DialogResult.No)
{
SqlCommand cmd = new SqlCommand("exec insertcatego @description,@quality,@quantity,@priceUnit,@vat,@totalprice", con);
error is coming when i confirm my insert.

Matt T Heffron 1-Aug-12 16:42pm

If I had to guess, from the code that is shown, is the SqlConnection value con possibly null? Try setting the debugger to break on the exception thrown to see what is really happening:
Visual Studio menu: Debug -> Exceptions...
expand the Common Language Runtime Exceptions and System items
select the checkbox in the Thrown column for System.NullReferenceException
then select OK.
Also, I would NOT proceed by checking for (dh != DialogResult.No), but only for (dh == DialogResult.Yes) because closing the MessageBox will not return No. Ensure the user REALLY intended to proceed.

Gilbertinino 2-Aug-12 6:07am

Thanks, now it is working!!!

Matt T Heffron 2-Aug-12 12:30pm

Great! What was the actual problem?
(And be sure to "Accept" the appropriate answer.)

Manoj Kumar Choubey 1-Aug-12 9:26am

Please confirm " exec insertcatego @description,@quality,@quantity,@priceUnit,@vat,@totalprice " ?

Manoj Kumar Choubey 1-Aug-12 9:27am

What is your table name and its fields name where you want to insert record ....

Gilbertinino 1-Aug-12 10:41am

category which is my table name.
field are listed below:

idcat
description
quality nvarchar
quantity
priceUnit
vat
totalprice

3 solutions

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bbirajdar · Answer 1 · 2012-08-01T04:21:00

Corrected your code. you were missing to assign the SqlConnection object to SqlCommand command object.

C#

DialogResult dh = MessageBox.Show("DO YOU WANT TO INSERT ?", "CONFIRM YOUR INSERT", System.Windows.Forms.MessageBoxButtons.YesNo);
                if (dh != DialogResult.No)
                {
                    SqlCommand cmd = new SqlCommand("exec insertcatego @description,@quality,@quantity,@priceUnit,@vat,@totalprice", con);
                    cmd.Parameters.AddWithValue("@description", txtDesc.Text);
                    cmd.Parameters.AddWithValue("@quality", comboBoxQuality.SelectedValue.ToString());
                    cmd.Parameters.AddWithValue("@quantity", txtQant.Text);
                    cmd.Parameters.AddWithValue("@priceUnit", txtpUnt.Text);
                    cmd.Parameters.AddWithValue("@vat", txtVat.Text);
                    cmd.Parameters.AddWithValue("@totalprice", txtTotP.Text);
                    //con.Close(); 
                    cmd.Connection=new SqlConnection("your connectionString here" );//Added line of code
                    con.Open();
                    cmd.ExecuteNonQuery();
                    frmcategory_Load(sender, e);
                    MessageBox.Show("SUCCESSFULL INSERT");
                }
            }
            catch (Exception a)
            {
                MessageBox.Show(a.Message.ToString());
            }
        }

Good luck !!!

Vani Kulkarni · Answer 2 · 2012-08-01T03:17:00

Solution 1

Refer the following link for the exception details:
Object reference not set to an instance of an object.[^]

Posted 1-Aug-12 3:17am

Vani Kulkarni

Manoj Kumar Choubey · Answer 3 · 2012-08-03T03:16:00

   DialogResult dh = MessageBox.Show("DO YOU WANT TO INSERT ?", "CONFIRM YOUR INSERT", System.Windows.Forms.MessageBoxButtons.YesNo);
        if (dh != DialogResult.No)
        {
    con.Open();
    SqlCommand cmd = new SqlCommand("INSERT INTO  category(description,quality, priceUnit,vat,totalprice) VALUES( @description, @quality, @priceUnit, @vat, @totalprice)", conn);

            cmd.Parameters.AddWithValue("@description", txtDesc.Text);
            cmd.Parameters.AddWithValue("@quality", comboBoxQuality.SelectedValue.ToString());
            cmd.Parameters.AddWithValue("@quantity", txtQant.Text);
            cmd.Parameters.AddWithValue("@priceUnit", txtpUnt.Text);
            cmd.Parameters.AddWithValue("@vat", txtVat.Text);
            cmd.Parameters.AddWithValue("@totalprice", txtTotP.Text);

            cmd.ExecuteNonQuery();
            con.Close();
    frmcategory_Load(sender, e);

            MessageBox.Show("SUCCESSFULL INSERT");
        }
    }
    catch (Exception a)
    {
        MessageBox.Show(a.Message.ToString());
    }
}

C#

error persisting while inserting a record in database"object reference not set to an instance of an object"

3 solutions

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