Using VB.Net, I'm looking for best practices in dealing with the following idiom:[code]What I really want is something VB.Net doesn't offer -- additional and simultaneous iterators on For Each statements.[code]I'm interested in both Linq and non-Linq recommendations, comments about Copy method design, comparisions to C# or other languages.
View 3 RepliesI am working on a parser for a serial data protocol. I have an overarching Packet class, a couple sub-classes such as CommandPacket and StatusPacket, and then a few sub-classes of each of those:
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While I don't think it is entirely relelvant to the discussion, I am doing this in VB.NET. There is also a similar (but not quite the same) question posted here: Java - subclass validation design pattern
What is the proper design pattern for custom events in .NET (VB or C#).
I am refering to custom events, where in you override the AddHandler, RemoveHander, and RaiseEvent methods.
I've been studying design patterns off-and-on now for a project I've recently been working on. I've been fortunate with this last one not to have to work with databases, but will soon have an opportunity.
View 8 RepliesI'm trying to replicate a design pattern used in a graphical programming language called LabVIEW. One thread produces commands, and another thread, or series of threads, consumes the commands.This is very similar to using Queues in VB...but there doesn't seem to be an easy way to start the consumer thread when new items are added to the queue.
Here is what I would like to accomplish, please let me know if there is a straightforward way to accomplish this with out of box .Net functionality.1) Start the Consumer Thread...it sits idle, waiting for some new commands to appear in its Queue.2) Producer places a few commands into the Queue. Example: "Home X Axis", "Home Y Axis", "Initialize Pump", "Display Ready Message"3) Consumer thread 'wakes up' at seeing the new commands, then performs the 4 tasks specified in 2.4) Consumer thread goes 'idle' again, and simply waits for new commands to appear in the Queue.
Process can continue on and on forever. The main problem I see with Queues is that there is no 'Wait for Something to Appear in Queue then Retrieve it" functionality. I don't want to use a perpetual loop to keep checking ever n milliseconds.
With C# anonymous delegates, we can avoid declaration of extra method, I know in VB.NET they're not available, but is there a design pattern that I can use so that I can avoid writing an extra method each time? I need it for SPSecurity.RunWithElevatedPrivileges which will be used a lot of times in our code.
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Suppose I have two events:
Public Sub Control1Updated() Handles control1.TextChanged
control2.Text = SomeFunction(control1.Text)
End Sub
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Basically the pairs of {control1.Text, control2.Text} and {control2.Text, control1.Text} should be the same. If control1.Text is changed to let's say "a" then control2.Text is ALWAYS "b". If control2.Text is changed to "b" then control1.Text is ALWAYS "a". How do I achieve this with events without going into an infinite loop? [the best I can think of is to make a check if the other control.Text is already the desired value].
In the MVC design pattern we must use a controller(s) classes.
What are the fucntions (features) of the controller apart from handling communication bewteen Model and View?e.eg; can we include input validation code in the controller?
In teh MVC design pattern, Controller is strongly related to the view (GUI). IN my application i need to generated a new BrandID, i used stored procedure to retreive the highest BrandID from teh DB (The model calls the stored procedure and sends the retreival value to the Controller), then in the controller increments the BrandID by "1" to create a new brand ID. SInce, controller is strogly related to "view", should i include this "brandID increment" part in teh controller or in the model classes?
View 3 RepliesI have a winform which allows people to edit data from a database, to simplify things assume there is a Customer table in database with 3 fields - Name, City, Country. Through winform(s) people can Add/Edit/Delete customers.For each of these actions we need to save:
What the field names are (Name,City,Country in this case)What the field values were before they were modified What the field values are after they are modified.If the action is Add or Delete then 2 and 3 will be the same.I have already implemented this using XMLSerialisation (but not using any of the design patterns) and my XML output looks like this.
<?xml version="1.0" encoding="utf-8"?>
<ActivityItem xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
<UserID>26</UserID>
<FormTitle>frmCustomer</FormTitle>
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The solution can handle different areas of the system with different number of fields (i.e the same thing works when you are modifying Products for instance).is there a well defined design pattern to deal with this kind of behavior?
having difficulty with understanding object lifetime / instantiation.I have a windows from with a datagridview and a panel. The datagridview has a checkbox column and a list of names which is populated from a database.The panel has a few text boxes (e.g. name, age, favourite sports team) and a 'save changes' button.
The idea is that when the user selects a person in the datagridview by checking the appropriate checkbox then the panel shows the relevant data for that person (name, age, fav sports team) by pulling the data from a database. If the user would like to update the person's details they can do so by typing in the textboxes and then clicking the 'save changes' button. All quite simple so far.
The way I have designed this is to have a 'panel' class and to create an instance when the user checks a checkbox.(NB - the reason I have created a 'panel' class is that I intend to replicate the datagridview and panel on other tabpages within my form and thought it would be useful to have a generic 'panel' class that I could re-use.)
My code looks a bit like this:
If CheckBoxClicked Then
Dim UpdatePanel As New UpdatePanel(MyForm.NameTextBox, MyForm.AgeTextBox, MyForm.FavSportTeamTextBox, MyForm.SaveButton)
UpdatePanel.GetData()
...
When the user clicks the SaveButton the data is updated to the database and I have a display message (simple textbox) which says "Update successful" and displays for 5 seconds before hiding itself.
Here is the problem:Suppose a user checks a checkbox, reviews the data and does not make any changes, and then checks another checkbox and decides to update the data by clicking the 'save changes' button. What happens is that the "Update successful" message is displayed twice.
I think this is because every time the user checks a checkbox an instance of UpdatePanel is created. If a I select five different people using the checkboxes and then hit 'save changes' I get five "Update successful" messages.
I am not sure how to overcome this. It feels like each time a checkbox is clicked I need to check if an instance of UpdatePanel exists and then destroy it. I tried using UpdatePanel = Nothing and also investigated IDisposable and GC.Collect() but with no luck.
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Assume you have controls A, B, C, D and E all with a Visibility property. You also have states 1,2,3,4,5 and 6 in which various combinations of your controls would be displayed. Currently this is being handled by switch statements for each state: i.e.
Select Case PageState
case "1"
a.visible = false
b.visible = true
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As you can imagine, this becomes a pain as every state needs a show/hide statement for each control. How can I refactor this so that adding controls and/or states becomes trivial?My first instinct is to extend the control and add a collection of states that it should display for but this sounds like overkill.
Edit:I was deliberately vague in my question in case this has other implications. In my current instance the "controls" in question are ASP Panels. Does that change anything?
One of the problems that I constantly see with Winforms applications is that the GUI thread is stuck while a long-running task is running or just plain stops refreshing (yes, I know - needs threading). Is there a code template/design pattern I can use when reacting to mouse clicks or button presses? Should there be a processing thread always running in the GUI app? Basically, how do I write a great Winforms Application that is easy to maintain and doesn't have any quirky refresh bugs?
View 4 RepliesI have created my webpage in asp.net in 1024*768 resolution, my problem was that when i change my monitor resolution then the controls in my webpage will be displayed in unmanaged manner .
How to arrange items in my webpage which support multiple resolution ...
Whatever the resolution of my monitor the controls in my webpage will display as it is as managed in 1024*768 reolution !
I seem to have reached a limit on the size of the form. I cannot make the form longer and I need to add more fields. Is there a limit on how many fields can be included in a form?
View 1 RepliesI searched codeplex and google. I have found so many such as tustena but unfortunately they are not domain driven based and in these solutions I could not find a good modelling documents or references. i am a newbie in CRM but I am sensetive to design it with solid object-oriented fundamentals. Any reference or open source solution especifically for CRM design and implementaion in .NET? Cheers
View 1 Repliesi am having trouble putting a value in a textbox. Each time a ticket is sold i put the total price in a textbox, each time a ticket is sold for the same concert it increases by adding its self to the total price. It works at the first sale, but after that it breaks down. here is the code
Private Function DisplayMoneyTaken() As Integer
Dim totalMoney As Integer
'open the database connection
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Getting error filling grid view from reading through data table:
Dim myDataTable As DataTable = myDataSet.Tables("SunTrust")
Dim myRow As DataRow
Dim i As Integer = 1
Try
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Error:Index was out of range. Must be non-negative and less than the size of the collection.Parameter name: index
I am using Sub to format datagridview but during Form_Load this error occur. There are rows in datasource and dg.row.count is > 0.
.Columns(0).Width = 50 <==== ERROR HERE
.Columns(1).Width = 150
.Columns(2).Width = 80
.Columns(0).HeaderText = "ID"
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What im trying to do is send vars to a flash file.The following is my code:
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
Dim oTitle As New ArrayList
Dim oSub As New ArrayList
Dim oRate As New ArrayList
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What I'm expecting the output to display is something like "t1=value&s1=value&r1=rate&t2=value&s2=value&r2=rat&t3=value&s3=value&r3=rat" But... i keep getting this exception: index was out of range. must be non negative and less than the size of the collection. Parameter name: INDEX.
I have a datagridview, with 3 columns, each containing dropdown filters (in the column header). Of the 3 columns, 2 are working perfectly fine, but whenever I try to filter the 3rd column, it gives me this error: (Also all of the column's have the ColumnType property set to: DataGridViewAutoFilterTextBoxColumn) "Index was out of range. Must be non-negative and less than size of the collection. Parameter name: index." The error points to the part that begins with "If dgv1.Rows(e.RowIndex)..."
Private Sub dgvWPS_CellFormatting(ByVal sender As Object, ByVal e As System.Windows.Forms.DataGridViewCellFormattingEventArgs) Handles dgv1.CellFormatting
If e.ColumnIndex = 1 Then
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i am trying to get the value into the cur_stock where item_id = datagrdiview.curentcell.value.I am lookin out for the solution since couple of days, but couldnt figure it out.Well, m trying to make this work on CellMouse click event
Below is my vb.net code:
Private Sub DataGridView_stockout_CellMouseClick(ByVal sender As Object, ByVal e As System.Windows.Forms.DataGridViewCellMouseEventArgs) Handles DataGridView_stockout.CellMouseClick
Dim i As Integer = Stock_checkDataSet1.Tables(0).Rows.Count - 1
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Trying to input a high setpoint, low setpoint, a % load, and number of compressors, then calculate the temp that all compressors are off. Then build a datagridview with the staging of compressors from all off to all on for each compressor up to 10 compressors.I am trying to insert headers from 1 to 10 compressors (Variable) with the text "Comp1", "Comp2", etc....Two rows with header. I am trying to use an array with index number to insert the text, but that is where my problem happens."Index was out of range".Here is my code
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Dim i As Integer, num1, num2, num3, num4, alloff As Single, stg As Single
TextBox1.Focus()[code].....
I've got the web browser with tabs in all working fine, but there's one bug, i can add tabs, delete em, etc.. but when i delete a tab then go to create a new tab, it gives me the error: InvalidArgument=Value of '6' is not valid for 'index'. Parameter name: index '6' is the number of tabs i had open.Here's the bit of code i use to create the tabs with the browser in it:
vbcode
Dim browse As New WebBrowser
browse.Name = "b1"
browse.Dock = DockStyle.Fill
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When the selected index changes I for a second time this code errors.
vb.net
lvReports.SelectedItems.Item(0).SubItems.Item(2).Text
with this error message
InvalidArgument=Value of '0' is not valid for 'index'. Parameter name: index
Why is this?It worked for the listviews.click event perfectly.
I am coding a program for a movie trivia game that randomly shows a movie quote and the the user selects a movie name from a combo box that matches. I used a array for the movie quotes and a comboBox for the movie names. I have coded a portion of the program but I am stuck on how to compare the array quote being shown to what movie the user selects from the comboBox. I have tried numerous different things but none seem to work right. The way I have it coded now it shows that every movie I pick that it is right even if it is wrong. I am going to show part of the code here and also attach the entire solution for anyone that needs it .
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I am working in VB 2008 and I have set up a datagridview to display rows of data which can then be selected. When I select the first row I get the error: Index was out of range. Must be non-negative and less than the size of the collection. When I select any other row the program executes as it should. From what I have learned so far is that the DataGridView has an index of -1 and that it counts the header row as part of the index which is the -1.When I select the first row through either DataGridView1_RowHeaderMouseClick or DataGridView1_CellContentClick the index is 0 for the first record. If the index is 0 I think it would fire off, but I have no idea what is happening behind the scenes. I can check the index, so when it is 0 and the code attempts to access the row, that is when I get the message.On an index number of 1 and up the code executes fine.So, is there a way to re-index the DataGridView, or is there a work around/fix for this issue?
View 2 RepliesHow can i get the Column Index and the Row Index when I click on the ListView?The ListView1.FocusedItem.GetSubItemAt(e.X, e.Y).Text function only gets the text of the first column, I can't find the option of getting the Index of the Column and Row upon clicking.
View 9 RepliesI am running a VB.NET program and having an error of "Index was out of range. Must be non-negative and less than the size of the collection. Parameter name: index".My code looks like below.
If Status.InvokeRequired Then
Try
Status.Invoke(New delegateoneArg(AddressOf onChangeEvent), ws)[code].....
Im just going to have to get used to this language for the rest of the semester And smohd, I will get back to you with my problem. That "Me..." control is so random. Not like JAVA Why am I getting an error with totalGrade
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