"In what circumstances will the following boolean expression evaluate to true?
strAlphabet.indexOf(StrCharacter) >= 0 And _
strAlphabet.indexOf(StrCharacter) < 0
Once you have answered that question, you should be able to complete this description: the expression indicates whether strCharacter is ..... but is not...."
This is probably a basic question, but I have never used this syntax before. Can someone tell me in detail how this expression evaluates to true? [Assuming IsOdd is a boolean type].
Dim i As Integer = 3
IsOdd = (i And 1) = 1
I am use to coding in php and everything does not need to evaluate to true or falst in an if statement. I have this [code] How would I make that return true or false?
View 3 RepliesI am using a class to check for certain words in my application to prevent SQL Injection. In the class, there is a for loop that tries to match a specific word with the words from a blacklist. If there is a match, I must redirect to the system's error page. However, when a match is found and I try to redirect, I keep getting the error "Unable to evaluate expression."
[Code]....
I have this line in some
Integer.TryParse(ThisRow.Item("DatumID").ToString, n)
ThisRow is a datarow. The "DatumID" in this case happens to be an empty string, but is not Null. When I break on this line, and try to evaluate it by highlighting it and pressing Shift+F9, I get the message "Unable to evaluate expression". Interestingly, it is actually evaluating correctly (since the item holds an empty string, TryParse returns False).
I have tested this in every way I could think of (mostly I thought I had left out a parenthesis in my expression, but that wasn't true). So why won't that expression evaluate when tested, even though it is actually working correctly?
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].....
I have a form which creates a new school talk appointment. In my database, there is a column called 'active' which is boolean (true or false). Then everytime I creates a new school talk appointment and added it to database, the active is automatically set to 'false'. how to make it set to 'true' instead?
View 10 RepliesI have one test class which having few variables declared in the header of the class where it will be accessed for all the subroutines and functions in the class. Here's the sample of my declaration:
Private m_dblMaxPwrLimit As Double
Private m_dblMaxPower As Double
Private m_intHalfPwrIndex As Short
Private m_intMaxPwrIndex As Short
After that, I have one Private Function which need to access some of the variables declare in above. Part of my function is show as below:
Private Function GetPmaxIndex(ByVal Serial As Short) As Boolean
Dim i As Short
Dim Total As Short
[code]....
The problem is when I step into the line of m_dblMaxPower and m_intMaxPwrIndex, I can't see the value of these variables which is suppose I can see it as in VB6. Additionally, when I put Add Watch for these variables, it showed 'unable to evaluate expression'. I guess it is not being used and I think something is wrong with my declaration but I do not how should I declare it corretly because as for VB6, we can declare all the variables in the header of the class and we can use it for all the subroutine/function within the class.
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???
In debug mode I get into a line that evaluates to false because the expression cannot be evaluated because of "Cannot evaluate expression because the code of the current method is optimized." Program does not assert or error out. If Item.Length then . . . (Here when I hover the mouse it displays "Cannot evaluate expression because the code of the current method is optimized"). What interesting is that it only occurs in one of .vb files.BTW, I'm programming in Compact Framework.
View 4 RepliesI am making a simple calculator that will evaluate functions I have a entry box and the user types in simple equations i.e. 1+4*3/5=? how would i make this evaluate the string?
View 7 RepliesI am working with some VB.Net code that seems to be casting a boolean value to an integer using CInt(myBoolean). The odd thing that is happening is that it returns -1 if the value is true. For example:
CInt(True) // returns -1
CInt(False) // returns 0
Is this common in other languages? I thought that a boolean would be 1 if true and 0 if false. Also, is there a way to make VB assign 1 to true instead of assigning -1?
I'm deserializing a custom object from a file to an object in my app using the XmlSerializer. My issue is that I want a field in the object to default to "True" rather than "False" for a new property that doesn't exist in the file that I am deserializing from.
By default, .Net is assigning this value to be false because it doesn't exist in the file and I want it to default to True if it doesn't exist. I used the System.ComponentModel.DefaultValue(True) attribute on the field in the definition of the object, but that didn't work. Does anyone know how to do this?
I have a math program that I am working on. One of the exercises has a random word and 6 radiobuttons. The user has to select the radiobutton that displays the exact number of letters in the random word. What I am having trouble with is creating a Public Function to check if the answer selected is the correct one. The radio buttons are within a groupbox. The Public Function returns a boolean True or False.
View 4 RepliesDim method1 = Function(x As Integer, ByRef y As Integer) As Boolean
If x = y Then
Return True
Else
[code]....
I am trying to create a procedure which will evaluate a string expression as if it were a line of code...Kind of like what a graphing calculator does when you enter a formula. Does anyone have any experience with this in VB? I have an example of C++ code which uses CodeDom, but I am a bit rusty with my C++!
View 4 RepliesThis is probably a really basic (no pun intended) question, but I can't seem to find an answer anywhere.Why does the result of func1 return False and func2 returns True? On every other test I have done, integer 1 is converted to boolean true and 0 to false. Works ok if I just set rtnValue to 1 or 0.
I have a basic bubble sorting algorithm that can sort either A-Z or in numerical order with just the change of a "less than" or "more than". However, I have to use the code twice in order for it to sort correctly.
'Sub Sort(ByVal array As Object)
'--A-Z
If Array(i) > Array(i +1) Then
[code]....
Anyway, if there is a way to do it, that'll allow me to have just one sort instead of having two sorts which use the same sorting algorithm, but just a different comparator.
I am developing a VB.NET ASPX file and am trying to run a string query in VB.NET, but now I get the above error message. How can I determine the cause? Some of the code in this
[Code]...
Dim MyString as String = "Various very long strings, 1000 of lines. Here \n \n \n to <TR> here."
Dim MyMatch As MatchCollection
MyMatch = Regex.Matches(MyString, "Here((.|\n|\r)*?)<\/TR>", RegexOptions.Multiline)
Dim MyArray(MyMatch.Count - 1)
This code stalls. I was trying to find out why my app stalls, and never breaks, or reports an error. I found out, that it stalls in the last line of code, where Count in MyMatch sometimes is not numeric. It has various error values, such as: "Unable to evaluate expression", "Evaluation of expression or statement timed out", and similar.I was trying to find solution, searching the internet, but no success. On MSDN site, there are 2 simple advice: a.) Verify that the entered code is correct. b.) Simplify your expression so that it takes less time to execute.My code is correct. It works on some strings, and stalls on other. I couldn't simplify it more, because strings to test with matches are different every time. They differ in length, and also in content
Is there any better performance by checking for a true value like this:
[CODE]..............
Than like this:
[CODE]..............
I have a datagridview, and I want to get an array of rows, or rows indexes in which boolean column "Aktywny" is set to True.Obviously I can Do it using loop, but LINQ will be much faster for sure...
View 1 RepliesI have a Windows Forms which contains a whole bunch of different text items on TextBoxes, Labels, and ComboBoxes. I then catalog what is written in these Textboxes and selected in these ComboBoxes in XML files so that they can be reopened later. Because what goes into the Textboxes and ComboBoxes are physical quantities, they have units (for examples "Inches," or "Lbs," etc.) which are the text of the Labels themselves. Multiple quantities share similar units, so I don't allow the user to change each one individually, but instead change a unit globally (for example, all weights in "Kilogram" instead of "Lb").
The units themselves are Public Properties of a separate class which I named "MyDBClass". The properties raise events when they are Set, so that objects data-bound to them change as well.When I initialize the main Windows form, I instantiate a class of type "MyDBClass," set all the unit defaults ("LengthShort = mm," etc.), and create a databinding for the Labels to the "MyDBClass" properties (e.g. ctrl.DataBindings.Add("Text", MyDBClass, "LengthS") ). From then on, the only way the user can change the units is to use my MenuStrip and select "New" (which erases all text and sets the MyDBClass properties back to default), use the MenuStrip and select "Open" (which opens an XML file, reads the "Unit" elements in, and uses them to set the MYDBClass properties), or use the MenuStrip and select "Change Units" (which brings up a dialog with a handful of ComboBoxes containing possible units, and then sets the properties of the MyDBClass based on what the user selected in the dialog).
Having said ALL of that, I can finally get to the problem- one of my units ("SpringRate") does not change when the user selects "New" or "Change Units" from the MenuStrip. It will only change when the user opens an XML file. This makes no sense, as the act of opening an XML file calls the exact same code as selecting "New" from the MenuStrip (which is that is sets the properties of the MyDBClass). The label is also identical to its surrounding labels and the ComboBox which selects the unit is identical to its surrounding ComboBoxes (I tend to use Copy/Paste when working in Design mode). I even put Try->Catch blocks around the Property's Set code and the code inside the other Subs which calls it.
I have the need to disable multiple controls based on specific circumstances.[code]Thing is, this doesn't work for ToolStrip items. Is there a way to do this without checking the type of each control passed to the function?
View 7 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 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 RepliesI got this Error. below is my code.
GenerateTheList is function.Need help
Private Sub buttGenerate_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles buttGenerate.Click
Dim thread1 As New Thread(New ThreadStart(GenerateTheList))
thread1.Start()
End Sub
While looking in the dataset designer for a database table I am doing in visual basic 2008 I found a line for expressions under the property menu for a specific column. I need to know the code that I would put in this expression line so that this column adds up the numbers I input into three other columns and displays that number in the column. I need it to automatically calculate this for each row in the database table.
View 13 RepliesI am trying to write following expression on a datacolumn. But it results in error:Replicate('*', nLevel) + NameWhere: Replicate() is a user defined function (in a module). nLevel and Name are two other columns in same data table.
View 3 Replies