NullReferenceException - Getting The String Contained In Each Item?
Feb 7, 2009
I keep getting the error " Object reference not set to an instance of an object." in relation to the line : selA = CType(lstStudents.Items(r.Index), String)
Background: I have a winForm app that registers a user in the database based on the information provided, auto-generates a random password and username, and e-mails the user a link to take an application based on the marketing company selected. Problem: hen the user clicks "Send Invitation" with data inputted iton all fields except the bundles listbox in debug, the NullReferenceException Error is thrown highlighting the line: Dim MCShort As String = Trim(splitMC(0))How do I fix this issue Here's a screenshot of the web app: Here's the code of the Send_Button_Click method off default.asx.vb:
Private Sub Send_Button_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Send_Button.Click 'TODO Add code to validate that all selections that are reaquired are met.
If we have a string that contains for example "01_1A" in ascii, I would like to take first two chars and following two chars after mark and send it as hex format, like &H1 and &H1A.
Note that I would not convert ascii to hex. I am asking for something like &H(var).
I am in great trouble, I have a project on visual studio 2008 and I getting connectionstring using ConfigurationManager.ConnectionStrings("connestionstring") .ConnectionString. this project have a app.config file which contain
getting connected using an app.config instead of hardcoding since yesterday evening and I either can't find any more info on the net that helps or I'm too new to understand it all. The exception is occurring on the line assigning the connectionstring to 'returnvalue'.
Imports System.Configuration Imports System.Data.SqlClient Public Class Form1
Let's say I have a page Test.aspx along with test.aspx.vb.Test.aspx.vb contains a class name "TestClass". In that class I have method1(), method2() and method3()I need to be able to call one of those methods, but I can't hard code it, the method to be executed comes from a string.
I can't do Select Case StringContainingTheNameOfTheDesiredMethod Case "Method1"
Regarding my college project. i'm working on a sales system . i have a form which consist of all the following information( item code , item name , item price , quantity of item ) which is display using a data grid . data input by user using text box and all this information will be stored in a database(sales database) i'm using ms access 2007. the grand total will be displayed in a text box . and amount paid will be input in a text box too , my major problem now is how to i create a reciept that will have all this information of the purcase. i have a reciept button . what the next step ? i dont have any idea how to get the reciept done.
I have a list box on the form which functions as a copy/paste. When you copy something, it is automatically added to the list box as a "clipboard helper". Here is the problem,however: if the text is more than 1 line, the list box does not show all the text.It ends up looking messy.So getting back to my question, is it possible to make the list box item height for an item depending on the amount of lines that item contains?This is a one line sentence in the list box and should take up one line.This is a multi line sentence in the list box and should take up two lines for item height.
I'm writing an application to help manage an employee database. It displays the current entries in a ListView control using the SELECT FROM sql string and allows entry into the database using the INSERT INTO sql string. What I want to do is have the user select an item from the listview and be able to delete it from the database. How I'm trying to go about it is by detecting when the user presses 'Delete'. When they do, the program gets the string value of the item, hands it off to a variable, and the variable goes into a DELETE FROM sql string and deletes the row in the database.
I have multiselect disabled in the control so only 1 selection is possible at a time. I don't know how to detect the Delete key or how to get the string value of a listview item into a variable. If I know how to do these two things, I can work out the rest of the application. I'm still kinda new at this kind of stuff, so any responses will have to be dumbed down a little.
In my application I have a listbox and SelectionMode should be MultiSimple because users need to see which items they selected. In another tab we have another listbox this one should show all the selection users had done in first tab. Private Sub
I am trying to get each item in a list box into a string array. However, I keep getting an index error and I am not sure why. I am doing this so i can perform a LINQ on the array.
Error:InvalidArgument=Value of '16' is not valid for 'index'.Parameter name: index
First field contains checkbox named chkSelect and second column is a label which is binded with EmailId. <asp:GridView ID="gvwNewsLetter" runat="server" AutoGenerateColumns="false" DataKeyNames="UserID"> <Columns>[code]......
When I check each checkbox I have to display mailid in corresponding row in a textarea which is outside gridview like" [url].... If I uncheck inbetween I have to remove that particular id from textbox.
how can i select an item in the listview from a string. ex.i'm loading the listview w/c: directory folders and i have a checkbox to show or hide hidden folders. no problems there.the problem is when i click an item in the listview and check or uncheck the checkbox, the listview reloads w/a new set of items.
i already have a string to get the selected item before reloading the listview, but i cannot seem to figure out how to select that same item in the listview.
Using the following code to add results from sql to a listview. Is there anyway that I can make a comparison from the reader against all currently existing item strings?
vb.net LstResults.Items.Clear() If con.State <> ConnectionState.Open Then Try con.Close()
I am trying to remove an item from a String() (just splitted a text into lines to that string()), and could not find how to do this. Are there even ways to do this?
I want succeed in having a file contained in my executable. This means that I must be able to copy it alone on any folder in the local system.I can upload it somewhere and then make my VB program do download it, but what if the user is online ? And I want it to be only one exe.
in propertygrid having name property .. How to restrict user only type in name property maximum 50 characters.. how to do this..always user is enter only 50 character ..after enter 51 character don't allow to typing.. This is the code i am adding Item in propertygrid..
<Category("Misc")> <Browsable(True)> <DisplayName("(Name)")> <Description("Indicates the name of the control to identify on the page")> _ Public Property Name() As String Get
I'm trying to write a small app which can be used in order to log off Citrix Sessions. Citrix Sessions can be logged off via cmd or a batch file using this method:
[Code]...
So basically what I want to do is to select each listbox item that matches one of the hits from the cmd command. Probably the servername that gives a different result than "No User exists for" How can something like this be achieved?
I'm kind of stuck on this one, and i know it's going to be something simple, but I just can't come up with the solution. I want to be able to assign a background color for each item in a listview with a predefined string or other variable type, so when item's are added to the listview and they contain a specific string, the background color for that item will be changed to the predefined color which is stored in a string (or other variable). When I attempt to change the background color of the listview item using a string ie. "Blue" I get an error.[code]....