I started out with VB.NET but now mostly do C#. I never really got to grips with events in VB. I'm trying to translate an old VB.NET program (from 2002) into C#. I've dealt with everything apart from statements such as these:
Public Event UpgradeProgress(ByVal strProgressString As String, _
ByVal strCurrentFile As String, ByVal intProgressPercent As Integer, _
ByVal lngTimeRemaining As Long, ByRef blnCancel As Boolean)
[code]....
See
Public Class Form1
Dim sql As String
Dim conn As New OleDb.OleDbConnection
Dim da As New OleDb.OleDbDataAdapter
[CODE]...
The problem, The INSERT statement works fine in the form load but not in the button click event?
I am novice so my questions may be very simple or very stupid, please advice me anyway.I just need an if statement with a key press, so all I want to type in code is - if I press a letter on the keyboard ("a" for example) I will run the event I need in that if. So how would you write this if statement.
View 5 RepliesI need help with a month calendar. I want to write an If statement in a button_click event. I need an If statement that says if one date is selected then a label becomes visible. I cannot figure it out.
View 1 RepliesI have three tables set up in a MySQL database called "event", "status" and "user". (as shown below:
EVENT TABLE (below)
STATUS TABLE (below)
USER TABLE (below)
and when I get data from the event table I use the SQL query statement below to bind the persons first and last names together as one variable called "name" and then bind that name to the respective user_id; and so on. However when I make changes to the event table it doesn't show the changes I've made. I'm certain it has something to do with the way I'm retrieving the data.
SELECT CONCAT(u.lastname, ', ', u.firstname) AS Name
, s.message AS Message
, DATE_FORMAT(e.timestamp,'%b %d %Y - %r') AS DateTime[code].....
I'm trying to make a show/hide button. I want the show hide button to be attached to an object on a form. Right now I just have separate show/hide buttons set the 'visible' property to true/false respectively. I want to code something that will consolidate the two properties. But I don't know how to code an if statement into an event, in this case the click event.
I'm thinking I'd have to do something like create an array (which I'd have to read a tutorial on first) that would hold two numbers. So, if the object on my forum's default visible property is true then if the button was clicked once it would be set to false (1) and clicked again it would be true (2). So, the array would only remember two values (1 and 2) and I'd have to create something else that would remember the previous value (say, 2) and than get the array to spit out the only other value (say, 1) it holds. Then finally strip the value the array spit out and have it go through some kind of if statement that would set the true/false value.
Without posting the exact code I'd need to pull it off, how would I go about doing this? Am I on the right track, or is there a simpler way? I'm new to programming.
I get this error:
[Code]....
I have a button on a web page that I just need a little help with some extra code. I think I need a TRY, CATCH statement?, this is what I have so far: I have a simple web page that has a button which at the moment when pressed enables the user to add data to a DB table via a stored procedure.Once this button is pressed a pop up message box is displayed to let the user know the data has been passed. The user then needs to press the 'OK' button within this message box which then directs them to the home page of the site. This works fine.
The code for this is here:
Protected Sub btnAddRawData_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnAddRawData.Click
'database conn, this is linked to the web config file .AppSettings
Using dbconnection As New SqlConnection(ConfigurationManager.AppSettings("dbconnection"))
[code]....
As I don't want the user to enter duplicate records in the database (This could be done by the user navigating back to the page where the btnAddRawData_Click is located and pressing it again.), I have created a UNIQUE INDEX named 'DupRecords' to stop the user from commiting this data more than once that day.When I run the web page now I get the following message in my browser:
Cannot insert duplicate key row in object 'dbo.GasRawData' with unique index 'DupRecords'.The statement has been terminated.The solution I think, is to add a TRY, CATCH statement into the btnAddRawData_Click code.
Dim i As Integer
If Label1.Text = "" Then
i = BPORes_csvDataGridView.CurrentRow.Index
Label1.Text = BPORes_csvDataGridView.Item(0, i).Value
[CODE]...
I have this code in the click event for a button I want to be able to select a row in my datagridview then Hit the ok button and have it populate to text box1 if textbox1 is already filled then i want to go to textbox2 and so on, (total of 6) So far if extbox1 is empty "" and i click ok button it populates, when i click ok button again to textbox2 does not populate.
I am writing an application that has to read and interpret data stored in some PDF files. The reading part is done but I am only able to get a dump of all the words on a page and not the format of the words. What I mean is that if I have to extract a table, I am getting the numbers in the table but not the markup which defines the table.
Further, there is some formatting used which displays a few of these numbers within parentheses (meaning that those numbers are negative) but the parentheses themselves are not part of the text. Hence, I am not able to distinguish between positive and negative numbers present in the PDF table!
How do you get the PDF markup along with the text? Is a PDF similar in structure to an XML with tags used to markup tables etc.? If not, then, is there a resource which describes the salient features of the PDF DOM? I am using VBA and the Acrobat library (AcroExch etc.)
I am trying to use my first predicate and I generate the error:Method 'Public Function FindIndex(list As MyProgram.HTMLFiles) As Boolean' does not have the same signature as delegate 'Delegate Function Predicate(Of T)(obj As String) As Boolean'.[code]
View 12 RepliesI have this RichTextbox in my vb.net form and I would like to when a user click a button, for example to embold the selected text, how would I do this.Also, I do NOT want to use the standard vb.net expressions such as RichTextBox1.SelectedText.Font.Bold = true. I want to do something like RichTextbox1.SelectedRTF="[bold]" & RichTextBox1.SelectedRTF & "[/bold]" or whatever RTF looks like.Can I just add the RTF options random places or can a RichTextBox return an error if the text is in wrong format. I'm mostly looking for info on how to work with RTF without using the standard vb expressions.
View 1 RepliesMy goal is to read a data streaming from a machine the streaming is divided in tre main parts,the first is a 10 byte array that declare the length of the second and third part.The second one, the header, is a 22 DWORD (*32bit) ( 88 byte ) structured of mixed data types.I can easly read the value inside this header when the DWORD contains just one information using something like: [code] My problem starts because some of these DWORD contains several indipendent informations, for example DWORD #4 [ channel 2 peaks 31..16] [channel 1 peaks 15..0].For what I understood the first 16 bits ( so 2 bytes) are used to store the information of the first channel , while the second 16 bits are used for the second channel, I tryed converting the first 2 byte with System.BitConverter.ToUInt16()but without success.Can someone explain me what to do and how these numbers are supposed to be stored?
View 6 Repliesso i have a class called FOOTBALL,then another 3 classes/forms that inherit FOOTBALL, they control score (SCOREBOX), possession (POSSBOX), and quarter (QUARTERBOX).the FOOTBALL class has 4 variables, "score" (array of 2 ints), "teams" (array of 2 strings), "possession" (boolean), and "quarter" (int)after that i have another form called MAINBOX, which creates new instances of the 3 classes (SCOREBOX, POSSBOX, and QUARTERBOX) (like this: private scoring = new SCOREBOX)... however they all technically create their own FOOTBALL classes, so I cannot connect them.
View 4 RepliesIt is my understanding that in .Net 4.0, VB will have an in-memory compiler.
I have to admit I don't know a lot about the compilers so I'm trying to understand the advantage of this as compared to what we had before this. Also, will C# be coming out with the same type of compiler?
I'm confused on the results of this code. The results extracts the tag "div" but why isn't the results containing the word "Yoga"? Shouldn't the result have only one element because it should exit the for loop after finding the first element? The results show hundreds of elements
Dim ElementCollection2 As HtmlElementCollection = WebBrowser1.Document.GetElementsByTagName("div")
For Each curElement As HtmlElement In ElementCollection2
[code].....
I wanted to know what the main areas are and what the array is actually doing in the code. I know that dim is declaring the variables, but how do i exactly explain this code line by line.
PS: the areas in red are the main areas im trying to understand annotate.
Public Class Form1
Private Sub Label1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Label1.Click
End Sub
[code]....
If i have a class called A and a class called B, if B inherits A that means A is the super class and B is the subclass. I have been asked to describe why class A is not an abstract class but as i see it class A is an abstract class A, as it has been created for Class B to use in the future, is it something to do with Class B not being able to access the fields in Class A as although they are private by default?
[Code]...
As far as I understand from the docs, it seems that Application.Run() starts a message loop on the current thread, which in turns enables it to process user input (Is that right?).The overloaded version Application.Run(Form) basically does the same, only it exists when the form closes, and it shows the form by default.timer ticks after 20mns, and has to execute say approx. 15 tasks one by one, every time creating an instance of a progress dialog, initially hidden in the taskbar.
View 1 RepliesLooking at the following code snippet in VS2008 (this is from the SBS book)
Dim HumanAge As Integer = 0
If HumanAge <> 0 And 7 / HumanAge <= 1 Then
MsgBox("1 dog year or older")[code]....
I expect to get a runtime error, because And evaluates both conditions, which is why in this case AndAlso should be the better operator to use. When I try this code there is no difference in behavior between 'And' & 'AndAlso'. In neither case I get a
runtime error, not even when I flip the conditions around. Is this by design, a lucky accident, or do I just not get it?
UPDATE: See the bottom of this question for what I did to solve the problem.I'm trying to understand how the ItemsSource and DataContext properties work in a Silverlight Toolkit DataGrid. I'm currently working with dummy data and trying to get the data in the DataGrid to update when the value of a combo box changes.
View 2 RepliesI have a situation in a program I'm writing where I'm not sure of the best way of coding a couple of objects and was hoping for a few pointers.I am using VB.NET 2003, so F/wrk v1.1. My business is horticultural in nature and I'm trying to help streamline the business with a new order fulfillment app.In my program, I have products. Some products don't have any component parts, but others are made up of a selection of plants.For example: we sell a trowel, which obviously doesn't have any component parts. But we also sell a large vegetable garden, which is made up of, say, 20 rocket plants, 30 salad plants, 5 spring onions, etc.[code]I believe the ProductContents table is technically referred to as a 'join table'?
I have written the classes in VB.NET which load, save, edit the Products and the Plants. I also have Manager classes which store collections of these objects (ProductMgr, PlantMgr).I have dealt with situations before with join tables where there are only two columns which are both FKs and both make up a composite PK (ie - to express a one-to-many relationship). This is pretty straightforward (using my product/plant tables as an example) because when I load an individual Product from the database, I also run a second SELECT query which returns any PlantIDs associated with that PlantID from ProductContents. I store that in an array of integers within the Product object. I can then load Plants from the PlantMgr object based on the PlantIDs stored in this array. I kind-of do the reverse when I save the Product to the database, I run a second INSERT query which updates the ProductContents table with the Plants associated with the Product.Where I'm getting stuck is with the inclusion of the extra 'Quantity' column. I can no longer store the PlantIDs in an array of Integers because I also need to store the Quantity associated with that Plant. I also can't use the PlantMgr object any more (to express which Plants are in each Product) because it also doesn't include any information about Quantity.I was just wondering if there is a standard way of handling this kind of situation, where I have a 'join table' which also includes extra columns as well as the two columns that identify the join.
I'm trying to figure out why the following VB.Net code seems unable to upload a file to my ISP's FTP server, since it doesn't report any error but I'm not getting the notification e-mail I'm supposed to receive once a file has been uploaded.So I launched the free Fiddler proxy on 127.0.0.1:7777, but it doesn't report any activity, even with its "Capture FTP Requests" option checked:[code]Is there a way to watch the FTP session to understand why the file seems to be uploaded successfully but I'm getting no success notification?
View 4 Replies a member mentioned, xml is similar to a txt file. txt files, i can manipulate quite well. so, if this is the case, it should not be to complicated to do as the thread title describes . that, of course is, if you already know how to even create an xml file. i do not. any and all input/suggestions welcomed, links for xml noobing welcomed as well.
i like: VB General google fast cars username password
I am working on a project, but the latest enhancement to it has me stumped currently. Here is what the class enhancement asks for:
Modify class time to provide a Tick method that increments the time by one second. Also provide methods IncrementMinute to increment the minute and methods IncrementHour to increment the Hour. The Trick method, the IncrementMinute method and the IncrementHour method should be called when you click the Add 1 to Second button, the Add 1 to Minute button and the Add 1 to Hour button, respectively. Be sure to test the following cases:
A) Incrementing into the next minute.
B) Incrementing into the next hour.
C) Incrementing into the next day (that is, 11:59:59 PM to 12:00:00 AM).
Here is my GUI:
The reason I am confused is currently my program already increments the seconds, minutes, and hours correctly (as shown in pic) for Cases A, B, C. But, I haven't added a Tick method which is what the enhancement to the class Time calls for. Here are the 2 classes I have so far:Time Class that the Tick method is supposed to be added to
Public Class Time
' declare Integer instance variables for the hour, minute and second
Private hourValue As Integer ' 0 - 23
Private minuteValue As Integer ' 0 - 59
[code]....
I am using AddHandler to wire a function to a control's event that I dynamically create:
[Code]...
This code is generating a run-time exception stating: Unable to cast object of type 'MyEventHandlerDelegate' to type 'System.EventHandler' What am I not understanding about System.Delegate even though AddHandler takes as an argument of type "System.Delegate"? What Type does "EventHandler need to be to cast to a type that AddHandler can accept?
How to determine when floating point limitations will cause errors in your calculations. For example the following code.
CalculateTotalTax = function (TaxRate, TaxFreePrice) {
return ((parseFloat(TaxFreePrice) / 100) * parseFloat(TaxRate)).toFixed(4);
};
I have been unable to input any two values that have caused for me an incorrect result for this method. If I remove the toFixed(4) I can infact see where the calculations start to lose accuracy (somewhere around the 6th decimal place). Having said that though, my understanding of floats is that even small numbers can sometimes fail to be represented or have I misunderstood and can 4 decimal places (for example) always be represented accurately.
MSDN explains floats as such... This means they cannot hold an exact representation of any quantity that is not a binary fraction (of the form k / (2 ^ n) where k and n are integers). Now I assume this applies to all floats (inlcuding those used in javascript). How can one determine if any specific method will be vulnerable to errors in floating point operations, at what precision will those errors materialize and what inputs will be required to produce those errors?
I have this code for an ownerdrawn list box that is repainting too frequently. It seems to be related to trying to scroll an event with a different height than normal. Here is the 'smallest code to reproduce the problem' that can be pasted into a blank form (erase the designer file) - VB version (c# of course does the same thing):
[Code]...
I'm working with an eprom emulator in trying to understand the command string write instructions. Here is what I have. [code] From what I know, the values in hex need to be converted to decimal first. What I'm not sure about is the checksum value needed. The instructions say Checksum =(1 byte truncated addition of all the above).
View 4 RepliesI've recently been updating a lot of my code to comply with proper n-tier architecture and OO programming, following examples from a book.I'm starting to get problems now because I don't fully understand the access modifiers.If I run the following code I get an error at the line
Dim clientFamilyDataAccessLayer As New ClientFamilyDAO
in the BLL at the point it creates an instance of the DAL. The full error message is: "The type initializer for 'ClientFamilyDAO' threw an exception. ---> System.NullReferenceException: Object reference not set to an instance of an object."
How do I use these function to create a list of ClientFamily objects that I can then work with?On my UI layer I'm creating a list of objects; ClientFamilies
Dim listOfClientFamilies As List(Of ClientFamily) = ClientFamily.GetClientFamiliesByKRM(selectedEmployee.StaffNumber)
This is the function in the BLL
Public Shared Function GetClientFamiliesByKRM(ByVal krmStaffNumber As Integer) As List(Of ClientFamily)
Dim clientFamilyDataAccessLayer As New ClientFamilyDAO
Return clientFamilyDataAccessLayer.GetClientFamiliesByKRM(krmStaffNumber)
End Function
and this is function in the DAL
Public Function GetClientFamiliesByKRM(ByVal staffNumber As Integer) As List(Of ClientFamily)
Dim currentConnection As SqlConnection = New SqlConnection(_connectionString)
Dim currentCommand As New SqlCommand
[code]....