I have a sub that initiates an instance of a library.object. That instance makes a connection to an instrument. Now I need to close it or change properties/run method from another sub. How do I reference this instance?
Public Class Form1
Private obj As AxCBMCOMMLib.AxCBMComm
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
[code]....
Whats the best way to instantiate a class so that i can have access to the object from diffreent forms and classes?
View 2 RepliesThe issue is when I try to add a new item to the ArrayList with the following code, it gives me an error:
vb Private Sub btnLabelAdd_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnLabelAdd.Click
Dim result As String = InputBox("New Filter Label:", "Label List")
[CODE]................
Object reference not set to an instance of an object.
I'm not really sure what I'm supposed to be doing with this. It's a new setting I just added and it's empty, so I'm not sure if that has anything to do with it or not. Anyone know what's going on and what needs to be done to get it to accept a value and not want to be "initialized"?
I have recently gotten my hands on a free, open-source IMAP connection API.So far, I have been successful in creating a connection to one of my accounts.Where I'm getting stuck is retrieving folders and/or emails from those folders.Does there happen to be anyone here that is familiar with this API, or even Gmail (particularly the folder structure for IMAP)?
If not, here is a link to the DLL that is listed on sourceforge and the company's website that created it (if you feel like testing):
Koolwired
Sourceforge - Koolwired API
I have created a test account so feel free to use the code below without worrying about username/password issues; I'll just delete it when I'm done with it.Here is the code I have made so far for making a connection:
Dim gSession As New Koolwired.Imap.ImapConnect("imap.gmail.com", 993, True)
Dim gAuthenticate As New Koolwired.Imap.ImapAuthenticate(gSession, "imap_test@serysoft.com", "imap_test")
Try
[code]....
When I run that code, I get an error that states:System.NullReferenceException: Object reference not sent to an instance of an object. (The bold line in the above code).
Now, I'm not sure exactly what that means. Does that mean it tried to access the server and "INBOX" doesn't exist so it gets returned a NULL value? Or is it possibly the coding itself?Maybe the Gmail folder system is weird due to the fact they use labels (even though from what I have read online, the labels act as the folders in the IMAP system).
What is the problem in below code.
d Public Sub filltextbox(ByVal dlist As String) Dim tb As TextBox = CType(Page.FindControl(dlist), TextBox) tb.Text = "hello" End Sub
Error : Object reference not set to an instance of an object.
look after the error i'm having.
module1.vb
Imports System.Data.SqlClient
Module dbconn
[code]....
I create one function to run any select query. and return the OdbcDataReader type.But some time if there is no data it through error : Object reference not set to an instance of an object I need to know how i can control if there is no data.
Public Function Select_From_AnyTable(ByVal sqls As String, ByVal ConStr As String) Dim conn As OdbcConnection conn = New OdbcConnection(ConStr) Dim cmd As OdbcCommand = conn.CreateCommand() conn.Open() cmd.CommandText = sqls Dim reader As OdbcDataReader = cmd.ExecuteReader While reader.Read() Return reader End While conn.Close() End Function Dim ei As OdbcDataReader = Select_From_AnyTable("SELECT loginname from usertable limit 1", conStr) msgbox(ei.item("loginname "))
If there is data it work well but if no record found it through the error.
Like every other program that you make when you code a button to open the next form it should open right. Well not in my case. I don't understand the problem that Visual Basics is not seeing my next form that I'm trying to open. When its in the Solution Explorer plain as day. Error below.An error occurred creating the form. See Exception.InnerException for details. The error is: Object reference not set to an instance of an object.show is not set to a object. All its doing is opening the next form. Ive use this code over an over. Now its giving me this C.O.S. error.
View 27 RepliesBasically all I am trying to do is to insert data entered in a text box(description) on the application form into database(sql2008) in vb.net. The vb code I wrote is below:
vb.net
Protected Sub Save_Click(ByVal sender As Object, ByVal e As EventArgs) Handles Save.Click
Dim note As String = Description.Text
[code]....
However when I click on save button, I get following message:
System.NullReferenceException: Object reference not set to an instance of an object.
What in this code might be causing this??This part of the code is Hilighted as causing the error.
My.Settings.Item(Holiday_" & i) = DirectCast(Me.Controls("ComboBox" & i.ToString), ComboBox).SelectedItem
Public Sub btn_Update_Click(ByVal sender As System.Object, ByVal e As System.EventArgs)
[code].....
I am trying to clear a dataset in case it has some data already in so that I can add data to it to search a database, but when I run the program and get to the point that it tries to clear the dataset I get this error message "Object reference not set to an instance of an object", here is my
dtasetUser.Tables("tblUsers").Clear()Also I get an error "The 'Microsoft.ACE.OleDB.12.0' provider is not registered on the local machine" when trying to fill the same dataset, on searching I have found it is because I am trying to open a 2010 Access document in VB08, but I have no idea how to remedy this and any instructions I have seen make no sense to me, so I would like help with that too please.
I'm trying to make a search textbox bring up certain records in a DataGrid. This is my code for that function:
Public Function Find(ByVal StrSearchString As String) As Boolean
DataGridView1.SelectionMode = DataGridViewSelectionMode.FullRowSelect
Dim intcount As Integer = 0
For Each Row As DataGridViewRow In DataGridView1.Rows
[code]....
The problem comes on this line:
If DataGridView1.Rows(intcount).Cells(0).Value.ToString = StrSearchString Then
I can't figure out what the unhandled exception is. Any ideas? I'm sure it's something very simple I'm overlooking.
I am using the IndexOf function of the string class to find a specific instance of a string. And based on that I have a logic to do something. Below is the example of what I am doing. The code is in production and is working fine. But for some instance I am getting an "Object reference not set error". Yeah its intermittent.The requestXML is a string of xml data passed in as a paramter to a subroutine. I am fetching the xml string as a form post in a request object. The only thing I could think of getting this kind of error is when the requestXML string varia
requestXml = Request("requestXML")
SubmitRequest(requestXml)
Private
Sub SubmitRequest(ByVal requestXml
[code]....
Dim dir_info As New DirectoryInfo(strDirectory)
dInfo = New DirectoryInfo(strDirectory)
Dim fs_infos() As FileInfo = dir_info.GetFiles("*")
[Code].....
I am trying to create a new ProductID and stored it in a variable intProdID and also to display it on the Label.
But I encounter this error message to my surprise: Object reference not set to an instance of an object
this part of coding generate the error message:Do While DR.Read[code]...
I recently copied a code from internet, which gives me an error of Object Reference Not Set To Instance Of Object, NULL POINTER EXCEPTION. I couldn't understand where the problem lies.[code...]
View 2 RepliesThis was just thrown on me. It operates fine on first load but if I clear the box and click on the button that fires this code I get the NullReferenceException error. Everything is Null or "" on load so basically I am just resetting it
If (Not Trim(txtAssessmentSelectedType.SelectedValue.ToString) Is DBNull.Value And Not Trim(txtAssessmentSelectedType.SelectedValue.ToString) = "") And ((Not Trim(txtAssessmentSelectedTypeLow.Text.ToString) Is DBNull.Value And Not Trim(txtAssessmentSelectedTypeLow.Text.ToString) = "") Or (Not Trim(txtAssessmentSelectedTypeHi.Text.ToString) Is DBNull.Value And Not Trim(txtAssessmentSelectedTypeHi.Text.ToString) = "")) Then
DoAssessment = True
Exit Function
End If
The following code gives me an error: Object reference not set to instance of an object[code]...
View 10 RepliesI am currently trying to reference a new form that has been created, but I am unsure how I reference a particular instance of the form.
The form that has been created can have up to 4 different instances. Each one is created from the menu. The code that is executed is identical, with a parameter passed 1,2,3,or 4 The form is created with
Dim newScreenDisplay As New ScreenDisplay
and has all the usual text boxes and buttons etc. on it.The display is then kept up to date by refreshing it from variables. This task is performed by a background thread.What I can't work out is how to reference the specific instance of the form that I created as they all have the same name (newScreenDisplay).
I'm showing a form like this[code]...
Then I am trying to update a progressbar on that form from a public sub in a module, but I don't know how to reference it. I can't use "Me" because I'm not doing the updating in the forms code
This is on my page load. I always encounter Object reference not set to an instance of an object on my ddlStatus drop down list.
HTML
Dim lnkUpdate As LinkButton = FormView1.FindControl("UpdateButton")
Dim ddlStatus As DropDownList = FormView1.FindControl("DropDownList4")
Dim lnkEdit As New LinkButton
Dim lnkDelete As New LinkButton
Dim CurrRow As GridViewRow
[Code] .....
I have Form1 calling Form2 and Form2 calling a sub from anther class on load that populates a combobox.The sub is throwing the exception "Reference not set to an instance of an Object". I do something nearly identical on the main form and it works perfectly.[code]
View 3 RepliesWhen I got a fieldsinfo-array of a class I know all of it's fields. Now, how can I access all of the fields of an instance of the same class by using the fieldsinfo-array? [code]I'm sure there exists a possiblity to get the value of the instance, but how?
View 5 RepliesI am trying to get the bound values from a row in a ListItem. I have a button on each row that when clicked will perform a task (sending an email message to the person who's name and email address is in that listitem row. So, I have an event handler tied to the listview, and I am trying to get to the underlying datarowview to extract the data items.Here's what I have in the event handler:
Protected Sub lvUsers_ItemCommand(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.ListViewCommandEventArgs) Handles lvUsers.ItemCommand
Dim diCurrentUser As ListViewDataItem = CType(e.Item, ListViewDataItem)[code]...
Now, it fails at the line where I am trying to access the contact_email element in the DataRowView object.What an I doing wrong?
I've written a new DAL and BLL, but when I try to create an instance of my class, I get an Object Reference error, is there anything particular I should be looking for? I am fairly new to this concept?
Call is such:Protected Sub btnSignin_Click(ByVal sender As Object, ByVal e As System.Web.UI.ImageClickEventArgs) Handles btnSignin.Click Dim l As New Log()l.Log = "Attempted staff login with username [" & txtUsername.Text & "] and password [" & txtPassword.Text & "]"
[Code]...
Intellisense highlights no problems and if I Build the web site in VS I get a few warnings about schema information in the web.config (unrelated), otherwise no problem.
Is it possible using Reflection or some other method to obtain a reference to a specific class instance from the name of that class instance? For example the framework for the applications I develop heavily uses public class instances such as:
Public bMyreference as MyReference = new MyReference
Then throughout the application bMyReference is used by custom controls and code. One of the properties of the custom controls is the "FieldName" which references a Property in these class instances (bMyReference.MyField) as a string. What I would like to be able to do is analyze this string "bMyReference.MyField" and then refer back to the actual Instance/Property.
In VB6 I would use an EVAL or something simular to convert the string to an actual object but this obviously doesn't work in VB.net. What I'm picturing is something like this:
Dim FieldName as String = MyControl.FieldName ' sets FielName to bMyReference.MyField
Dim FieldObject() as String = FieldName.Split(".") ' Split into the Object / Property
Dim myInstance as Object = ......... ' Obtain a reference to the Instance and set as myInstance
Dim myProperty = myInstance.GetType().GetProperty(FieldObject(1))
The code is shown below:-
Function fnt_db_JDE(ByVal connName As String, ByVal strSQL As String) As DataTable
Dim result As New DataTable
Dim dsSysConfig As New DataSet
Dim xmlPath As String = ini("Root") & "SysConfig.xml"
[code]....
The error is with the connStr = '' line.
Currently using Vb 2008 express edition i was trying to complete the tutorial on databases found here [URL] but i ran into the error, "Object reference not set to instance of an object" no one at school seems to know what i can do and they aren't experiencing this problem. i took a screenshot of the problem, it occurred when i was trying to navigate through the database. [URL]
View 2 RepliesI get this error:Reference to a non-shared member requires an object reference.When i compile on the following code section:
Private Sub statusBarToolStripMenuItem_Click(ByVal sender As Object, ByVal e As EventArgs)
ToolStripMenuItem.Checked = Not ToolStripMenuItem.Checked
statusStrip1.Visible = ToolStripMenuItem.Checked
[Code]...
I am using this exact code on another form in the same project without an issue, just with a different data source. Any ideas?
EDIT: Never mind, seems like it was a stupid naming scheme and VS was adding a bindingsource with a different name than I wanted.