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 Replies
This work nicely
Public Const test As ULong = 1 << 30
This doesn't work nicely
Public Const test As ULong = 1 << 31
[code].....
I have written a simple VB.net application which saves information to an RFID tag. I am now trying to compress my data. The solution I have come up with involves bitwire operation.Basically I store 2 numbers per 1 byte (0-9, 10 being a period, 12 possibly being a negative/positive flag,13,14,15 unused as of yet).The code I am using basically shifts the byte containing a number left, 4 spaces, then 'OR's it against another number.Therefore 12 is now represented as 00010010. The problem i'm having is decompressing. Obviously getting the '1' back is easy, as I just shift right 4, then grab it. I need to append or remove the last 4 bits.My solution after many headaches was to reverse the bit order, shift left 4, then reverse, then tostring it.
View 17 RepliesFrom 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].....
After 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 Repliesresult = SendMessage(buttonhandle, BM_GETSTATE, 0, 0)
buttonChecked = (result = BST_CHECKED)
Now I want to know whether the bit for BST_CHECKED is turned on or not.
How would I do that?
I can do
buttonChecked = (result % 2 = BST_CHECKED)
Is there a better way?
Original Code (VB.net): curStyle = curStyle And (Not ES_NUMBER)
Changed Code (C#):
curStyle = curStyle & (!ES_NUMBER);
But it is giving me this error: Operator '!' cannot be applied to operand of type 'long'ES_NUMBER is of data type long.I tried changing it to int, string, etc. All doesn't work.
When I run this command in PHP, I get:
[Code]...
The interesting thing is, that when I try to shift any number greater than int32 in .net, it yields bad results.. Every number under int32 (2147483647) yields the same results from php and c#.net or vb.net Is there a workaround for this in .net?
Did anyone else read this article under Visual Basic News? I thought it was a very bad treatment of the subject. I especially don't like articles like that when the code they post relies on Option Strict Off.
View 12 RepliesAccording to MSDN The And operator can act as a bitwise operator OR a logical operator.The only way to know if it is used as One operator or another is, If it is on the right side of an assignment operation? for example x = 3 AND 5. I cannot find any other instances where the bitwise operator would be used instead of the logical operator, are there?
View 1 RepliesHow do I bitwise shift right/left in VB.NET? Does it even have operators for this, or do I have to use some utility method?
View 4 RepliesI have an abstract user control(baseModule) that has a property that I plan on using a bitwise comparison on to determine what export types are supported by that module. In the designer of a module derived from baseModule, I am presented with a combobox with the ability to just select a single value (Html, Xml, etc.) I would like to be presented with a drop-down checked listbox so I could select which values I want.How can I accomplish this inside of VS2008? I've seen other properties support this.
Public Class ExportTypes
Public Enum ExportType
Html = 1
Xml = 2[code]......
I'm re-writing some old application in VB.NET to C# and ASP.NET 3.5. Everything is going OK but I have this problem - and, as the database will not be changed, I must find a solution to it.The old app saves the list o desired days (from Sunday to Saturday) in a byte. This is the way it do it:
If chkDaily.Checked Then
daysBitmask = 127 ' This is for a full week
Else
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m_ArchiveBoolean, m_HiddenBoolean, m_ReadOnlyBoolean, m_IndexedBoolean, m_CompressedBoolean are all form level booleans that's set from their appropriate Checkboxes on the form before this code runs in a BackgroundWorker.
Why is it that this code works:
Try
Dim fi As New FileInfo(element)
With fi
If m_ArchiveBoolean = False Then
[code]....
In this 2nd one attributes are being changed, but they're the wrong ones and I can't pinpoint it right off hand.
Edit: What the overall goal of this is that if the user has the attribute checkbox checked then the file needs to have it set, other wise the attribute (if it's present) needs to be unset.
I am trying to combine three Byte values to one Long value, like System.Drawing.Color.ToArgb() does.
I've looked up reference source code to find it and converted it to VB .NET:
Return CLng((CInt(red) << 16 Or CInt(green) << 8 Or blue Or CInt(alpha) << 24) And -1)
It works fine of course, but I don't really understand why alpha shifted by 24 is last, not first (so it would be in nice order 24, 16, 8). I don't really understand bitwise operations a lot. Also, this code snippet works for 4 bytes, which is redundant for me, I need just three bytes and I wonder if Long is still required when bytes are only three, wouldn't Integer do just fine in this case?
So, my question is, how do I rewrite this code to work with just 3 parameters? Do I need to use Long? And, I know this is silly, but is it possible to make byte shifting in order 16,8,0 instead of 16,8,0,24? It's really just aesthetics, but I am awful perfectionist.
m_ArchiveBoolean, m_HiddenBoolean, m_ReadOnlyBoolean, m_IndexedBoolean, m_CompressedBoolean are all form level booleans that's set from their appropriate Checkboxes on the form before this code runs in a BackgroundWorker.
Why is it that this code works:
Try
Dim fi As New FileInfo(element)
[code].....
I'm trying to convert code from Delphi to .Net. I'm stuck on one line:
//Delphi code ss := Copy(ss, Length(ss), 1) + Copy(ss, 1,Length(ss) - 1); 'vb.net code ss = ss.Substring(0, ss.Length - 1) + ss.Substring(1, ss.Length - 1)
Delphi combines the two substrings, while .Net just concatenate them like a copy.
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'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].....
