Null Reference Exception error

Question

4.00/5 (1 vote)

See more:

NullReferenceException Was Unhandled Error on line with code " newRow = dt.NewRow() " below

VB

Try
    If State = gModule.FormState.adStateAddMode Then
      'add a row
        Dim newRow As DataRow
        newRow = dt.NewRow()
        newRow("company") = txtbname.Text
        newRow("bid") = txtbid.Text
        newRow("biztype") = IIf(txtOccupation.Text = "", System.DBNull.Value, txtOccupation.Text)

Update 1:

VB

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
    Dim dt As DataTable = cnGetData.Tables("tbl_permits")
    If txtbname.Text = "" Or txtbname.Text = "" Then
        MsgBox("Please fill up Company Name Information.", MsgBoxStyle.Critical)
        Me.txtbname.Focus()
        Exit Sub
    End If
    Try
    If State = gModule.FormState.adStateAddMode Then
        ' add a row
        Dim nRow As DataRow nRow = dt.NewRow()

and I have also set the: Dim cnGetData As New DataSet()

Posted 22-May-11 19:13pm

joseph k

Updated 22-May-11 19:38pm

Venkatesh Mookkan

v3

Add a Solution

3 solutions

Solution 3

Thanks very much for your lead i got the problem, Actually i had not connected to the MySQL DB, i got it working.

Posted 22-May-11 20:20pm

joseph k

Comments

Hemant__Sharma 23-May-11 2:37am

Welcome.

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

Hemant__Sharma · Accepted Answer · 2011-05-22T19:15:00

Solution 1

the datatable "dt" is not initialized. i.e. it's nothing
check where the datatable is being created and initialized properly.

Thanks,
Hemant

Edit:
Now check your dataset where are you filling values in your dataset. you've created the dataset

Dim cnGetData As New DataSet()

but are you filling it with proper data and is it being filled with the table tbl_permits. The top most source of data here is Dataset and then there are tables if you've not filled the dataset properly.

Debug your code and watch if you have any table in cnGetData dataset

--Hemant

Posted 22-May-11 19:15pm

Hemant__Sharma

Updated 22-May-11 19:47pm

v2

Comments

Venkatesh Mookkan 23-May-11 1:18am

Good call!

joseph k 23-May-11 1:34am

Ok, Thanks for your response: check the code below as i have initialised dt to get data from a table:
<pre lang="vb">
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Dim dt As DataTable = cnGetData.Tables("tbl_permits")

If txtbname.Text = "" Or txtbname.Text = "" Then
MsgBox("Please fill up Company Name Information.", MsgBoxStyle.Critical)
Me.txtbname.Focus()

Exit Sub
End If

Try
If State = gModule.FormState.adStateAddMode Then
' add a row
Dim nRow As DataRow

nRow = dt.NewRow()</pre>

and I have also set the: Dim cnGetData As New DataSet()

Hemant__Sharma 23-May-11 1:48am

Check the updated solution

Hemant__Sharma 23-May-11 1:48am

Thanks @Venkatesh.

Venkatesh Mookkan · Accepted Answer · 2011-05-22T19:40:00

Solution 2

In the above case cnGetData.Tables("tbl_permits") is null.

Place a breakpoint on that line and check it cnGetData.Tables("tbl_permits") has any value in it.

Posted 22-May-11 19:40pm

Venkatesh Mookkan

Comments

joseph k 23-May-11 2:20am

Thanks, this was a very good lead to my problem, i solved it.

Venkatesh Mookkan 23-May-11 2:23am

You are welcome.