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.
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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 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]....
I 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 have problem when i click a ADD button, there is one null value in the textbox .. so the try catch statemnt is to catch that null value error but after that the catch is success but the button click never stop excute the statemnt till the end of the button event.
View 6 RepliesI was convinced that If <expression> Then <statement [:statement]> Else [statements] in concrete form of If a = b Then SayHello() Else SayBye() End has sense. I read article on msdn on If-then-else, but I forgot why I was reading, so I concluded, that snippet above means this
If a = b Then HelloIsSaid : IsNotEnded Else ByeIsSaid : IsEnded But I have tested it now, and I see, that Else without statement is nothing more than decoration. It would be pretty good if it had function I described. Do you think its good request? Or do you know any circumstance where this Else has some function?
y friend and I are re-learning Visual Basic, and we are stumped on this bit of code.
For intAsterisks As Integer = 0 To intLine - 1
lblAsterisks.Text = lblAsterisks.Text + "*"
Next
I have the following SQL:
[Code]...
I want to put it (the select count statement) in this LINQ statement so I can get the sales count in my linq statement: Dim TheLeads = (From L In DB.Leads Where L.IsDeleted = False Select L).ToList() Is this possible to do in LINQ?
add an if statement and an exit statement to my do loop that exits when my future value (FV) is greater than 1000, then to change the exit statement to a continue statement so my loop will continue even though my fv is greater then 1000, point is to get this to run even though my if statement doesnt do anything. problem something wrong in my code and an exception error (xception of type 'System.OverflowException' occurred in mscorlib.dll)
so can someone show me where or why I have an error is, what am I overthinking now! I could use a hint, OMG i could use a tutor for that matter
[Code]...
A co-worker wants to convert the following IfThenElseIf statement into a Select Case statement.
Explain why this is not possible.
If temperature = 100 Then
X = 0
ElseIf population > 1000 Then
X = 1
ElseIf rate < .1 Then
X = -1
End If
I cant get this SQL statement to insert any of the values in the form to add to the database
sql
sql = "INSERT INTO prevresults (ExamDate, ExamTime, CorrectAnswers, PassPercentage) VALUES (date.now, time.now, rightanswers, percentage.text)"
[code]....
I've read thru Iceplug's tutorial on control arrays and got it working. I tried to add a new event by basically copying his click event code and calling it a doubleclick event. I used the proper addhandler and assigned the correct name to my sub. I have the click event changing the background color to blue and the doubleclick event changing the background color to green. The background color does not change to green. Why?
Heres the tutorial with my new code encased in asterisks ...
Code:
Imports System
Imports System.Windows.Forms
Public Class form1
[CODE]...
I am using VB.NET for Windows applications. What is the difference between Load event,Activate event and Enter event in the Form and in which order the above event is executed.
View 2 RepliesI'm trying to validate a few things in a form I'm building. It has a datagrid with clients info (taken from an access database) and a few textboxes where the user can type some search criteria. The thing is that those same textboxes are used to add new clients to the database and to modify a client's information if one from the datagrid is selected, so I made it that the buttons to insert and modify clients are disabled on load and thenevery time the text on a textbox changes ("TextChanged" event) they become enabled. So far so good. But then I wanted to make it so when a client from the datagrid is selected both buttons become disabled again until the text on a textbox changes (to make sure they're adding a different client and not the same one that was
selected).
I tried using the CellClick event from the datagrid to disable the buttons, but since every time a client is selected from the datagrid the info is shown on the textboxes, this triggers the TextChanged event too, and the buttons become available.So, is there a way I can tell the TextChanged event not to be triggered when the CellClick event occurs?
Return statement which is true in an if statement
View 3 RepliesI'm writing something that will examine a function and rewrite that function in another language so basically if inside my function F1, i have this line of code var x=a.b(1) how do i break up the function body into symbols or "tokens"?I've searched around and thought that stuff in System.Reflection.MethodInfo.GetMethodBody would do the trick however that class doesn't seem to be able to have the capabilities to do what i want..dit 2:basically what I'm trying to do is to write a program in c#/vb and when i hit F5 a serializer function will (use reflection and) take the entire program (all the classes in that program) and serialize it into a single javascript file. of course javascript doesn't have the .net library so basically the C#/VB program will limit its use of classes to the .js library (which is a library written in c#/vb emulating the framework of javascript objects)
View 4 Replieshow to use them then before, but am still a little confused with a few aspects. Here goes:
1.) Lets say you have a method that checks for a certain condition(s) and if it fails Throws an exception. Does it have to be in a try/catch block? Meaning can the "Throw" statement exist in a block with no try/catch statement?
2.) Now lets say we have a method that has a try catch block and in it there is a throw statement. When the throw statement is executed does it first try to find an appropriate catch block in the same method or does it immediately go back to the calling method without looking at the catch statements in the current method where the exception was thrown?
3.) I created a custom exception class that inherits from ApplicationException. Next I created a method which has a catch block that catches this type of exception and does some action. Is the System(i.e CLR) smart enough to throw an exception of this type, or does it only throw exceptions from SystemException?
4.) I know that some people are more liberal in their use of exceptions and others use it more sparingly when truly strange stuff happen like the DB going down. I am writing code where I am getting some info back from the database, converting it and then storing it. Sometimes there might be data that comes back from the database and other times the field is empty and the Null value comes back. Therefore in the instances where Null comes back from the database I should not convert the value to anything, since I will get an error. What should I do in this situation? Should I let the CLR throw the exception when it goes to convert the Null value or should I check for the Null value and if it exists not convert?
5.) In general when I throw exceptions, is it sensible to only throw exceptions of the type Application Exception or are there instances where the programmer throws exceptions of the type SystemException?
I'm building a listview search feature in my app. (See the code below). It works really well, except if you search "T" then the code removes all items, if you search "t" then it removes every item except for those starting with "t". Is there any way to make a 'like' statement, or use some kind of wildcard to make the statement not case sensitive?
For Each itm As ListViewItem In ListView2.Items
If itm.Text Like TextBox1.Text & "*" Or itm.SubItems.Item(1).Text Like TextBox1.Text & "*" Then
Else
[code].....
I have a line of code that is working in one statement but not the second statement. I'm not sure what I'm doing wrong, I am learning slowly but surely, and it is by no small margin because of the ave found here =) The error is occuring in the intResult = intSelection x intCount line of the SECOND Do While Loop.
The blue squiggle line is under "intCount" just FYI
Dim intSelection As Integer
Dim intCount As Integer = 0
[code]....
I have the following vb code which works as expected when it's in a code-behind page. I tried to move it to a shared or component page since I will need to use it in multiple pages:
Imports Microsoft.VisualBasic
Public
Class DetTime
'Determine eastern time
[CODE]...
However the "if" statement shows an error " statement cannot appear outside of a method body" and the Microsoft solution is to "move statement into a procedure or subroutine"
The event handlers in my parent class are never called though the events are raised in the child class.
The Code:
Public Class childForm
Public Event checkboxchangedEvent(ByVal checkbox1 As Boolean, ByVal checkbox2 As Boolean)
Private Sub checkboxchanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles CheckBox1.CheckedChanged, CheckBox2.CheckedChanged
[code]....
I'm trying to complete this airline reservation application, but having a problem in this part of the question:Creat an event handler for the FlightBindingSource's PositionChanged event: select FlightBindingSource in the class Name combobox then select position changed in method name combobox to creat the FlightBindingSource's PositionChanged event handler. Write a code to access the currently displayed flight object and pass its flightNumber to method DisplayPassengers as a decimal.This Is my code so far:
HTML
Public Class AirlineReservationForm
Private database As New ReservationsDataClassesDataContext()
Private Sub FillAll()[code].....
Eg. ""vb.net" timer event trigger on purpose". This application is meant to run at all times to download a web page every minute. To avoid freezing the UI, I read that the best solution is to move the code from a While/Sleep loop to a Timer that will be triggered every minute. The problem I have, is that the user must wait for a minute before the event is triggered:
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Timer1.Interval = 60000
Timer1.Enabled = True
[CODE]...
Is it possible to force this event to occur instead of waiting for it?
I'm trying to execute different code depending on the button clicked (button 4 or 5) on Form1, but when I click on button5 to activitae the code on the Form2's Load event everything is Ok, but when I click the back button to return to Form 1 and click on the Button4 to activate the code on the Form2's Load event again, it doesn't active the Form's Load event, is there a way to form the form load event every time I access it from Form1? [code]
View 7 RepliesStarting from my understanding about Background worker control, I understands that the background worker runs the code in its "DoWork" method in a seperate thread, while ProgressChanged and RunWorkerCompleted events are executed on the main thread.In my senerio, I report the progress and under an specail condition my application displays a message box to the user in "ProgressChanged" method using MessageBox.Show(). and in "Run Worker Completed" event the application finalize some work. There the sequence is important, suppose that the message is of Yes or No type and finalization depends on it. Now when i run my application, the background worker triggers "ProgressChanged", but as soon as backgroundWorker's cancelAsync() is called the program leaves the current "ProgressChanged" method and executes "RunWorkerCompleted" code first.How can i make sure that the "Run Worker Completed" code executes only after the completion of ProgressChanged method.
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