I am developing an application for multi user using vb.net with back end as ms-access. For the table name as employee_master, there is a column, name as student_profile having datatype as Yes/No .
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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
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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 am trying to up a private sub routing based on the Text Changed Event for a listbox, inside of the event, I want to set a boolean variable to true. I have it set up, but for some reason it is not getting called.
Basically what I am doing is the user is being prompted to enter data in an input box. I am taking the data that is entered on the input box and populating it in a list box. I want to know if the text in the listbox has been changed, hence changing the blnIsChanged = True
Can I use text changed with a listbox???
I'm sure it is negligible, but given that I want to assign true to a boolean field from within a method, does this choice make any difference? If so, why? field = true; // could already be true, but I don't care
View 4 RepliesI 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
If Textbox1.Text = Nothing Then
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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 RepliesSo I had a smart idea to make a dictionary with all my variables so I could save them easily in chunks. This includes String, Boolean and Integers. When I was in Framework 3.5 I only had a few warnings about stuff that I didn't have coded in, but now in Framework 4 I am maxing out all my warnings with Implicit conversions. Personally I don't want to go to every number and put quotes around it put quotes around "True" because then it may change the method.
Public Function loadGeneral(ByVal fName As String) As Boolean
Dim tempDict As New Dictionary(Of String, String)
For Each kvp As KeyValuePair(Of String, String) In GeneralSettings
Dim v1 As String = kvp.Key
Dim v2 As String = QuizZing.My.Settings.GetSetting(fName, v1)
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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
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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
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A first chance exception of type 'System.NullReferenceException' occurred in MyApp.exe
A first chance exception of type 'System.ComponentModel.Win32Exception' occurred in System.dll
1- How can I check the size of a variable? Size in bytes, not length. (;
2- What data can be stored into byte variables? And what the maxium size of the variable?
3- How do I store data inside a byte variable?
To check if a setting has been set, I currently use:
If My.Settings.Username <> "" Then If this the best way to check? Is there a better way?
I have got a question to you. I want to know how I can check the listview items in form1.listview1.items and me.listview1.items to see that if both listview have got the same text property of the items then display the messagebox that says "you can't add the same items again. Please select a different item and try again!", otherwise display the messagebox that says "the items have been added".
View 2 RepliesI 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 RepliesThis line of code references a checkbox in a Gridview, how can I assign the value of the check box 1 or -1, I think it is for checked or unchecked, to a variable so that I can run an if statement against it, and change it to True or False?
dt.Rows(row.DataItemIndex)("DisplayString") = (CType((row.Cells(3).Controls(0)), CheckBox)).Checked
I want to check If a variable is equal to some values or not, for example:
if a = 1 or a = 5 or a = 7 or a = 10
is it possible to do it like sql:
if a in (1,5,7,10)
I have a BaseClass, a DerivedClass1 and a DerivedClass2 from a third party library. DerivedClass1 and DerivedClass2 both inherit from BaseClass.There's a ContainerClass, from the same library, with a member variable ActiveItem, which can be of DerivedClass1 or DerivedClass2, so it is declared as BaseClass.I want to know if ActiveItem is of DerivedClass1, as it can change in runtime without notice.If I do
Dim isDerivedClass1 as boolean = TypeOf(oject.ActiveItem) Is DerivedClass1
then I get a compile time error, telling me that ActiveItem can never be of DerivedClass1 type.I have tried several combinations of GetType and TypeOf but it doesn't seem possible to check this. I have also tried to declare an auxiliary DerivedClass1 variable and comparing their types, but haven't got any luck either.
Edit:The following code doesn't compile in vs2005 SP1.
Public Class Base
Public x As Integer
End Class
Public Class Derived1
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In Visual Studio 2010 is it possible to check the state of variables during run time. When a run time error occurs the error is highlighted and you are able to mouse over different variables to see their values when the error happened. I would like to do something similar except without the error.
View 7 RepliesI have a struct setup like the following[code]...
I then loop through a counter and add each PersonInfo object to the Dictionary. The Primary defaults to false if the Code is already in the Dictionary, but if it has not been inserted into the Dictionary, I want to set the Primary to True. It would be easy to check if the Code was the key, but I can't because the Code is not unique.
I have some web pages that include other pages, and I need to check if a variable (a string) has been declared in the page or not.
I was exploring try catch and finally, but im always getting a compiler error saying the variable doesnt exits.[code]...
I'd like to know if my textBox1 variable has the ABCAttribute. How can I check this?
View 3 RepliesDim myObject As Something There I defined my variable myObject of type Something. But, as you can see, I am giving it no value yet. Sometime on runtime I want to check if myObject is holding a value or not. I tried this: If myObject <> Nothing Then But apparently I can't do such comparison.
View 3 RepliesI want to see if a variable's type is string or double type. How to do it in vb.net immediate window?
View 1 RepliesI've never really used the Check List Box in the past, however, for the recent program I am developing, I am using this control rather than individual check boxes scattered across the form.Anyway, I want to be able to program through code which items get checked in this checked list box. Specifically, I have a variable that contains the text of each check box that I want checked.With a normal check box, I can simply say:
Dim strNames As String
strNames = "John Doe, Mark Johnson, Mike Brown, Cindy Smith"
If strNames.ToString.Contains("Mike Brown") Then[code]....
I am trying to do a select case to see if a variable contains a list of the most common words in the English language.[CODE]....
Right now I get the hateful blue squiggly under b.contains with a message that overload resolution failed because no accessible 'contains' accepts this number of arguments. Any suggestions? Also this is my fourth thread is it better to make new threads as new questions come up or just role from one topic to the next during a project in one thread? I just don't want to make anyone mad for starting too many threads.
I am getting the error:"Range variable 'sender' hides a variable in an enclosing block or a range variable previously defined in the query expression."for this
Imports System.Data.SqlClient
Imports System.Linq
Public Class Form1
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I can select any other item from the table without the error. "sender" has the same properties as "receiver" in the SQL table.
I receive the error -
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I 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";
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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