There are a lot of interesting methods buried in VB.NET, and I'd hate to miss the one that "flips" a Boolean value.
What I'd like to do is something like:
Dim MyBool As Boolean = False
If <true statement> Then MyBool.FlipValue
Of course no method like that seems to exist in the Boolean type itself, but maybe there's another single-statement method that will accomplish the same thing.
From what I read it is a good convention to name a method that returns a boolean value with the prefix of "is" or "has". So in keeping with this convention I am trying to name a method in my program with this prefix but I am running Specifically I have a class called Day. It is a simple class with a few data members and one method that returns a boolean value of true or false. The name of the boolean variable is isSpecialDay. This class has a method called isSpecialDay which takes the date of the day, applies some criteria to the date and then sets the variable isSpecialDay to true or false. My problem is that the boolean variable is named isSpecialDay and so it the method. What should I do?
Public Class Day
Private TheDate as String
Private DayName as String
[code].....
I just found an error in the compiler. Newpath is a boolean and the compiler took and ran this[code....
View 1 Repliesi have problem when save boolean value to database. this my code vb.net
if bAdd then scmd.CommandText = "insert into products(prod_id,status) values(@prod_id,@status)"else scmd.CommandText = "update products set status=@status where prod_id=@prod_id"end if scmd.Parameters.Add(New OleDbParameter("@status", CBool(chkStatus.Checked))) scmd.Connection = dbConnDim iResult As Integer = scmd.ExecuteNonQuery
i get problem when execute query at line
scmd.ExecuteNonQuery
Data type mismatch in criteria expression
I am working with a multi form project. The long and short of it is that when i originally load form 1 ... all bool variables are false. Once i load form 2 and perform my operations some of my bool variables will be set to true.
I need to have some sort of object to listen for those changes. What i have come up with so far is the following. Private Sub patient_frm_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
[Code]...
The if statement will work but i need a way to make it keep looking for changes in the boolean variables.
What is a Boolean and what does it do in Visual Basic 2010?
View 8 RepliesI have a checkbox named chkFactureren.When I want to save the value of that checkbox to my ms access 2003 DB I get the error: oledbexception was unhandled by user code - data type mismatch in criteria expression
cmdUpdate.Parameters.AddWithValue("@Factureren", CBool(Me.chkFactureren.Checked))
Is there anyway to customize a variable to use both an integer and a boolean value?For example. I am kind of making a simulation engine and using GDI as a visual aid, I am generating a grid of tiles for objects to be displayed, but I do NOT want to repaint all the tiles just the ones that have changed, so that I can save fps.So I thought if I could set a variable for the "tile number", "how many objects there are on a tile", and a boolean value for whether or not the tile needs repainted.[code]
View 2 RepliesI have written a calculator program, and when the mouse clicks on the equals button, the button sets a boolean varaible to true, and then that variable can be used later.But I am wondering if the button control has it's own property that can indicate if it has been pressed?
View 1 RepliesIs there any way to invert the screen. For example, making upside down or having mirror effect?
View 1 RepliesAfter Filling a DataTable in GridView's DataSource . A column with check box Type appears but it created as read only column and I can't enable it or make it editable... even i tried .readonly = false and still can't be edited
View 1 RepliesI have a HTTP class that gets content from URL's, POST's content to URL's etc and then returns the raw HTML content.In the function inside of the class it detects if there is a HTTP error and if so I would like to return false but will this work if I have declared the function to return a String?
Code Sample of what I am trying to do (Note the Return Content & Return False if a HTTP error code is detected)Public Function Get_URL(ByVal URL As String) As String
[Code]...
I ran some code through an automatic translator for C# to VB, and it translated some code like this:Public Property Title As [String]How is this different to Public Property Title As String
View 3 RepliesI am working on a little Hardware interface project based on the Velleman k8055 board.The example code comes in VB.Net and I'm rewriting this into C#, mostly to have a chance to step through the code and make sense of it all.
One thing has me baffled though:At one stage they read all digital inputs and then set a checkbox based on the answer to the read digital inputs (which come back in an Integer) and then they AND this with a number:[code..]
I have not done Digital systems in a while and I understand what they are trying to do but what effect would it have to AND two numbers? Doesn't everything above 0 equate to true?How would you translate this to C#?
I am converting some C# code to VB, the following code is part of a function
if (bool.Parse(v["Parent"].ToString()))
{
e.Row.CssClass = "Parent";
[Code]....
The code throws an error "String was not recognized as a valid Boolean" But if I use this code
If CBool(v("Parent").ToString) = True Then
e.Row.CssClass = "Parent"
End If
It works fine, which is great
I am using a boolean embedded in a for next loop. I thought the value would ALWAYS default to false inside this loop, but it seems to hold the value of true inside the loop, even when moving to another value of i. What's up with this?
For i as integer = 0 to 5
im b as boolean
se boolean value later...
[code].....
I am working on my project to connect to a site. As I have created a boolean to check in the mysql database whether if the username and password is true or false.
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
[Code]...
I just wanted to know if it's possible to get an if statement to accept two strings into the same text box. An example of my code so far is below: (although please note that the program does not accept the strings after the "Or" boolean)
Private Sub btnpreview_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnpreview.Click
If cbox2.Checked Then
[code].....
I'm taking a course in Visual Basic 2010 and I'm trying to get a grasp on this new term called a flag. I kind of understand that it has something to do with a boolean condition. I don't quite understand what a flag is. I see references to it using the term flag. I understand it has something to do when a boolean, a condition triggers a flag. But what is the flag.
View 3 RepliesWhy does casting a boolean to a byte in .NET give the following output?
Code Snippit:
Dim x As Boolean = 1
Dim y As Byte = x 'Implicit conversion here from Boolean to Byte
System.Diagnostics.Debug.Print( _
[Code].....
Why does True (which commonly is referred to as an integer representation of 1) convert to 255 when casted to a byte?
If I try to put a string into a Boolean variable such as this:
Dim testValue As String = "True"
Dim bool1 As Boolean = testValue
With Option Strict On I get an error and the suggested fix is to change the second line to:
Dim bool1 As Boolean = CBool(testValue)
This is fine, But - what are the advantages / disadvantages of doing this instead:
Dim bool1 As Boolean = Boolean.Parse(testValue)
I'm working with Visual Basic 2008 Express. My application opens with the Terms screen, a form that asks the user to declare his acceptance of certain terms and conditions or to decline. If he accepts, the app opens the main screen, giving him access to all the app's facilities. If he declines, the app gives him a message and then closes. Whether he chooses to accept or decline, the app puts his decision in My.Settings so that it can be used next time the app is opened. In this way he is presented with the Terms screen on the next opening if he declined on the last run. But if he accepted on the last run, he is presented with the main screen on his next opening.
All works fine when I do a debug run. But when I build and publish the app onto my desktop it opens with the Main screen instead of the Terms screen.
why it works on F5 but not after publishing?
Public
Class frmTerms
Dim Accept As Boolean
[Code].....
I'm creating a program in which I have a publicly defined boolean value.Public boolOverallStatus As Boolean = True
and I need to execute some code whenever the boolean value changes. In previous applications, an actual form item change handled this, but it can be changed by several different subs.How would I handle this? I'm looking through msdn, but it's rather confusing. In a nutshell: How to execute code when the event of a boolean value changing occurs.
I have the following code in an Asp.Net user control:
Me.pnlAddComment.Visible = MyBase.Associate.IsAgent()
Me.lblRating.Visible = Me.pnlAddComment.Visible
Me.Rating1.Visible = Me.pnlAddComment.Visible
Now when I run this code, the value of MyBase.Associate.IsAgent() is true. Yet at no point is Me.pnlAddComment.Visible evaluating to true. When I output the results as Response.Write statements, it shows IsAgent = True, pnlAddComment.Visible = False. When I run it in debug mode, placing the line break on the second line above to allow the set to occur: I put the mouse over IsAgent and it displays "True"; I put the mouse over pnlAddComment.Visible and it displays "False".
A Co-worker suggested that it's possible that it's Panel.Visible black box code in the getter that allows the assignment to occur but returns false because some parent object is set (at that point in the code execution) to False. I've reviewed the parent objects and at no time do any of them appear to be set to not visible.
If this were a reference type I might be convinced that some other process is modifying the reference between this assignment and when it is actually used (at Render), but this is happening right at this line of code.What would cause this boolean assignment to behave this way without throwing an exception?
Solution:The answer turned out to be a parent object in the control hierarchy located outside of the user control itself. Since nothing was explicitly set to false, and I agreed with @Shadow Wizard, @Damien_The_Unbeliever and @CodeMonkey1 that it had to be some outside control influencing the panel at that point, I decided to put a recursive while loop to test the parent of each user control in the hierarchy at that point:
Dim o as Object = Me.pnlAddComment.Parent
While o IsNot Nothing
Me.lblMessage.Text &= "<br />" & o.ID & ": " & o.Visible.ToString()
o = o.Parent
End While
Then I just ran this on the server and the output came back with the full visibility of each control in the chain. What ended up occurring is that this control was contained within a view control within a MultiView. This view control is expected to be visible as it is supposed to be the ActiveView for this particular call, but at the point in the life cycle when my code is run, the view has not been identified as the active view. Since it's not officially active, the view is implicitly false, and all child controls return a value of false when Visible is queried.
The rest of the assignments behave as expected from that point. The lblRating control is set to false (permanently) because at that moment the proper visibility setting for pnlAddComment is false. The lesson I've learned here is not to make control visibilities dependent on each other in this fashion when there is an alternative (and just as simple) method.
I want to perform a bitwise-AND operation in VB.NET, taking a Short (16-bit) variable and ANDing it with '0000000011111111' (thereby retaining only the least-significant byte / 8 least-significant bits).
View 3 RepliesI'm pretty new to Vb so I'm not sure of all the correct terminology etc.
Private Sub Add_mousedown(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Add.MouseDown
Dim Addition As Boolean
[code].....
How,in VB.net 2010, a checked checkbox(boolean) from a form to insert as a string in an SQL database like a character "T" or "F"
View 3 RepliesHaving a little issue with my boolean statement. It is not changing the value to true after you click it. Its a basic function just not working correctly and Im pretty stumped on why. I mean its a simple yes or no concept. The button is on or off is the basic concept.
Private Sub btn_Backhoe_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btn_Backhoe.Click
Dim InUse As Boolean
'Switch On/Off[code].......
i have a form with text boxes for username, initials, and password on.Also on this form are a few checkboxes which at the minute i simply want to save their state to SQL as true or false depending if ticked or not. The checkboxes or text boxes are not bound to anything, and are used only for creating a new record in the table.There is a gridview below these boxes showing already created records.The code im using to insert to SQL with is:
If String.IsNullOrEmpty(UsernameTb.Text) Then
MsgBox("You must enter a Username!")
Else[code].....
For some reason when i create a new record, it saves the check state as -1 for checked, and 0 for unchecked. the table columns are varchar(5) for the check boxes.Using checkboxname.checkstate doesent work either - that saves the state as 1 or 0 (as opposed to -1 and 0)On another form i made for editing existing entries, i have the same text boxes and check boxes, which are bound so they show the record details. when using that form to EDIT an entry, it saves the check box states as "True" or "False" as it should do.Im completely stumped here, because if i create a new user it then breaks the gridview showing users, because it throws up error messages about "-1 not being valid boolean" when it attempts to render each check box in a grid view. how i can make the insert save the check box state as boolean?
I have a boolean check property of my check boxes in VB.NET. how can I send that value to SQL server having a bit data type
View 4 Replies