In an application I am working on I have created a product class which represents an inventory item. I have also created an inventory class which represents a collection of product objects.In the constructor of the Inventory class I load 4 products into a product collection. Each product consists of a code, description price and quantity. Within the form load i would like to add a procedure that loads each products code property into a combo box.Obviously I could do this by hard coding the values but I would like to loop through the collection of products and populate the combo box with the codes contained inside the product collection. This is what I am struggling with. Below is the code for my inventory and product class.
Public Class Product
Private sCode As String
Private sDescription As String
In an application I am working on I have created a product class which represents an inventory item. I have also created an inventory class which represents a collection of product objects. In the constructor of the Inventory class I load 4 products into a product collection. Each product consists of a code, description price and quantity.
I'm trying to loop through a collection object in vb2010.The code was originally used in Vb6 The book said that I needed to code a NewEnumerator method first in order to be able to loop through my collection. I coded the following:
[code]...
It gives an error for IUnknown, staging that IUnknown is not accessible in this context because it is a 'Friend'.In the line in the function I removed the Set since it's no longer needed.The error message for this line is '_NewEnum' is not a member of 'Microsoft.VisualBasic.Collection'What are these messages and how do I fix this in VB 2010?m_colCourse is not a system collection.
I got two form. form 1 i ask the user a number of guest form 2 i ask each guest their name, their age i decide to make a loop base on the number of guest but then i got this error. NullReferenceException was unhandled how to solve this...i underline under my code
Private Sub btnBook_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnBook.Click iTest = CInt(txtChildren.Text Do Until (iCounter = iTest) And (bIsNextClicked = True) PassengersDetails(iCounter).ShowDialog() Loop End Sub
Whenever I try to create a new CD object I get a stack overflow. I want a parameter to be passed into mediaFactory so that it could be determined what type of media is created. Why I might be having problems with this when I do this "Dim media As CD = New CD()" Public MustInherit Class MediaFactory Inherits MediaContext Implements IMedia Public Sub New(ByVal typeId As Integer) [Code] .....
I am using a loop to update properties of each object of a set of custom objects. The routine knows which controls to update because the controls value is not empty, I don't want the routine setting the corresponding properties to nothing when the control is empty. Now I know how to do this perfectly fine with IF statements such as:
CODE:
But this feels really redundant doing that same IF block over and over for each property/control combination, I thought about creating a separate routine that takes the control as an argument and does all the repetitive IF blocks but I don't know how I could also pass an object property to tell the routine to update that particular property.
Makes the following statement about the code below:
**"The computer evaluates the loop condition in the Do...Loop statment to determine whether the loop instructions should be processed. In this case, the inputsales <> String.Empty condition compares the contenst of the input sales variable to the String.Empty value. As you know the String.Empty value represents a zero length, or empty, string if the inputsales variable is empty, the loop condition evaluates to True and the computer process the loop instructions. *If on the other hand the inputsales variable is not empty, the loop condition evaluates to false and the computer skips over the loop instructions.
Based on the code I think it is the opposite: ...that while the inputsales value is not empty it should evaluate to true and process the loop and if it is empty it should evaluate to false and skip the loop?
I am somewhat new to object oriented programming and am attempting to flatten a Linq object hierarchy by using a shim class.how to initalize a derived class with property values from a base class?I have two objects, a base object with about 100 properties, and a derived object which inherits from the base object and adds a few additional properties beyond those of the base object. My simple constructor creates the derived object, but I am looking for a way to initialize the derived object properties with values from the base object.Right now I am using reflection to iterate over the properties individually and I suspect there may be a better way. The following example shows my shim class constructor for the derived class, and two properties:
newProperty1 - a new string property of the derived class
flattenedProperty2 - a new string property of the derived class, copied from a 2nd-level object of the base class
Code example:
Public Class derivedObj Inherits baseObj Private _newProperty1 As String[code].......
Is this the correct constructor approach to flatten the object hierarchy using a shim class? My second question relates to initialization of properties in the derived class. The constructor above creates the derived object, but what is the best way to initialize the derived object properties with values from the base object? The following code uses reflection to iterate over the properties individually, but I suspect there may be a better way.
Code example:
' property names are in the string array fieldNames
'baseObjQuery is an ienumerable of baseObj
'derivedObjList is a list of derivedObj[code].....
Is there a simple way to initialize values for the properties in the derived object based upon the values of the common properties in the base object?
I am constructing a program, i am new to Visual Basic, but i have past programming experience. I was wondering if anyone knew how to form a loop that could...lets say calculate the answer when two numbers are added together,and it would repeat this thousands of times, etc. And if there is a way, would it be possible to calculate the time taken to complete this loop.
I have written a function that gets the alexa ranking of a given url, now this function works perfectly but I want to loop through a ListView of urls and grab the alexa rank of each item (url) with my function.The code works great if I put a MessageBox in the loop to test that the function is returning a value but when I remove the MessageBox the loop does not work.I need it to loop through adding each result without a MessageBox stop in each loop.
vb For Each Item In ListView1.Items Dim result As Integer result = GetAlexaRank(Item.Text)
So I made a simple patform game where the player has to jump quickly while the platforms move to the bottom of the screen, as to not touch the bottom of the screen. But, I need to know how to create a loop to loop the locations of the platform. This means that after twenty or so platforms, the same platforms come up again, so that the player will have an "endless" game. I've declared all the platform's locations relative to the location of the first repeating platform:
I have this little application that runs a SQL query works great, now I want to have a Start Button run the and display results then System.Threading.Thread.Sleep(300 * 1000) for 5 min then run again and display results and loop till I buttonstop_click. unsure if the sleep is the best method.
I am new to VB programming. I have the following code. When I execute my program only the last value from the loop is displayed in the label. I do write my code so that all of the values (years 1 to 5) show up in the label?
I am getting following error whenever I want to use IIf function inside entity framework query.
LINQ to Entities does not recognize the method 'System.Object IIf(Boolean, System.Object, System.Object)' method, and this method cannot be translated into a store expression.
Occasionally I encountered this exception message while trying to download file from a server using System.Net.FtpWebRequest and System.Net.FtpWebResponse Object.
Download a file.ftpRequest_DL.Method = WebRequestMethods.Ftp.DownloadFile get the response object Dim ftpResponse_DL As FtpWebResponse = CType(ftpRequest_DL.GetResponse, FtpWebResponse)
If I declare my object at the beggining of my page class, and instantiate it in a dropdownlist selected_index change event. Shouldn't this object be available thru out the entire page and also persist thru a postback? I lose the object in my selected date change event in my calendar.
I have an ssis package that takes a flat file and dumps it to SQL. During that process, 150 columns need to have '-' and '.' removed from them. I have done this using a Script Transformation.
Public Overrides Sub Input0_ProcessInputRow(ByVal Row As Input0Buffer) Dim column As IDTSInputColumn90 Dim rowType As Type = Row.GetType()
[code]....
Edit I've discovered that this line is the problem
Dim strCol As String = columnValue.GetValue(Row, Nothing).ToString()
I am trying to start the process with the following parameters When I try to start it though I get an System.nullreferenceexception: Object reference not set to an instance of an object
Dim exepath As String = Application.StartupPath + "inffmpeg.exe" Dim sr As StreamReader Dim cmd As String = " -i """ + input + """ -ar 22050 -y """ + output + """" Dim ffmpegOutput As String
I have an object that is defined as a global variable based on custom class. Within that class I have an event that gets fired a certain intervals. These events are fired on the same thread as where the object is declared. How do I create a global object, but have the events within that object fire on a separate thread?
i am using VB.net 2003 and i am trying to get the number of rows of a dataset from form1 into form2 in order to use it for something else and i am getting the error"System.NullReferenceException occured...Additional information: object reference not set to an instance of an object"...my code is like this:in form1:Public x as integer= me.dataset.table.rows.count here it gives me the error
I am getting this error when I try to print my report. Here is my print code.
Private Sub PrintToolStripMenuItem_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles PrintToolStripMenuItem.Click Dim Print_Dialog As New PrintDialog
[code].....
Here is my error: System.NullReference Exception: Object reference not set to an instance of an object.
I'm trying to set the format of a column in a datagridview.When I put the format statement in the on load event for the form, it has no effect. When I put it in the cellformatting event I get the "Object reference not set to an instance of an object" error. I checked the column name. What I am doing wrong?
This is the code:Private Sub MeetingTblDataGridView_CellFormatting(ByVal sender As Object, ByVal e As System.Windows.Forms.DataGridViewCellFormattingEventArgs) Handles MeetingTblDataGridView.CellFormatting Me.MeetingTblDataGridView.Columns("Starttime").DefaultCellStyle.Format = "HH:mm:ss" End Sub What I'm trying to do is get rid of the date part of a Date/Time field (stored in an Access database) in a datagridview column.
I know how to handle a single objects property changed event very easily. I want to handle a objects property changed event that is part of another object.
Given Object:
[ObjectY = Y] + Public WithEvents X As ObjectX
I would like to do something like:
Private Sub XPropertyChanged() Handles Y.X.PropertyChanged
Right now I need to create a object that equals the object inside that object and then handle this variable pointers property changed, but that is just annoying.
