Evaluate Algebraic Expressions In VB NET?
Mar 30, 2011I am looking for a way to simplify algebraic expressions in VB.NET. It is preferred if you can give me a link to a pre-written library or class.
View 1 RepliesI am looking for a way to simplify algebraic expressions in VB.NET. It is preferred if you can give me a link to a pre-written library or class.
View 1 Repliesif i do not need to evaluate all the expressions, am i right to say that there are benefits and no disadvantages of using AndAlso compared to using And
example:
if a=b And f=g And y=k
can be better done with:
if a=b AndAlso f=g AndAlso y=k
algebratic tecniques in VB, that don't work
View 3 RepliesI store a formula in the database such as the following:GrossIncome+(Overtime/0.5)-Deductions=BasicNetIncome
I am able to substitute the string representations with actually values entered, thus:1000+(150*0.5)-100=BasicNetIncome
Then I remove the '=BasicNetIncome', thus:
1000+(150*0.5)-100
How can evaluate the above equation to return a result:
[Code]...
At the moment I'm in the process of building a class that can handle more advanced mathematical equations and processes. Essentially my end goal is to to have my class capable of processing anything you'd learn in Elementary Algebra through College Algebra. So far I am able to multiply monomials and order polynomials.. However for the most part the equations in questioned being processed have to be in correct form. IE Point-Slope Form, Y-Intercept Form, etc etc. I'm just curious as to how I can go about "validating an equation type by it's current form".
View 5 RepliesI'm trying to evaluate a lastname and then set a value. so first two characters of last name btw M-MI would be M1, MJ-MZ would be M2
View 1 RepliesI have this code and it evaluates to false instead of a string. All its doing is building a string.
[Code]...
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 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."
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So I am trying to evaluate 3 conditions in an if statement. Its not working how I would assume it should. I basically want to do this:
vb.net
If PGN = &HEF007E And PGNData(0) = &H58 And (PGNData(1) And &H40) = &H40 Then IgnOn = True Else IgnOn = False
If I write it in that manner it gives inconsistent results. If I workaround by writing it this way it works perfectly:
vb.net
If PGN = &HEF007E And PGNData(0) = &H58 Then
If (PGNData(1) And &H40) = &H40 Then IgnOn = True Else IgnOn = False
Endif
What is the proper way to do this with only one if statement?
I have functions in my program that stop after it reaches a Return line but I need the function to continue in case what I want the function to return changes. Is there a workaround for this or a way to force the function to continue after a return?
I made a Test Program to demonstrate the problem. It is a Form that contains only a button.
Here is the source code:
[Code]...
The messagebox always says "It returned False" when if it continued going through the code like I want it to it would have returned true.
I have an LLBLGen Pro project which has generated VB.Net 2.0 Self Servicing code.I have a function to return a list of custom structures based on a search using the generated code.I would like to supply a Dictionary of FieldNames and Values to this function and for each one add a new Predicate Expression to the search.How can I check the String within the dictionary that represents the Field name and work out which EntityField to add the Predciate Expression for?
Dim dbFiles As New AllFilesCollection
Dim dbFilter As New PredicateExpression
If Not String.IsNullOrEmpty(ClientName) Then
[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 am new to VB.NET and I keep telling myself there must be a better way to do what I need to do several times a day which is look into a list and see if that one field is set to true anywhere in that list.
So far, I've been using the For Each statement:
[Code]...
But I know some of the other languages can do something like: if ListOfPlayers(*).isActive == true
which just seems more concise and to the point.
I have a Winforms project that is loosely based on MVVM. Security is implemented by the domain layer by using the PrincipalPermissionAttribute, [cod]e...
View 1 RepliesI'm reading a tutorial provided by someone at my university, and it claims that if you're debugging a VB.NET program, you can hover over a conditional (e.g. "Age > 13") and it will be evaluated. However, in VB 2010 Express, I am not seeing this functionality.
I believe the tutorial may have been written for a previous version of VB.NET, so I was wondering if anyone could tell me if this used to work and has been removed, or whether it has never existed?!
I am able to hover over a variable and see it's current value, and I can even "Watch" an expression (such as the conditional), but the tutorial claims[code]...
How can I use the Evaluate function in VB.net in Visual Studio 2008 so that to evaluate a string which consist of 2 variables to be evaluated.[code]...
View 2 RepliesI 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 need the create a function with two variables Price1 and Price2 and the following rule:
if Price1 > Price2 at time t and not (Price1>Price2) at time t-1 Then
result=true
else
result=false
I should be able to use a loop to store the time t and t-1 Price1 and Price2 values.How can I do this in VB.net
[code] please help me how to get and/or evaluate object from this json string with VB.Net.
View 1 RepliesI have a device that is continuously sending text over a TCP port and I want to write a VB.net application that will read and evaluate this data. Each line of text that arrives over the port can be of varying length and each value in the line is separated by a comma. I need to separate out these values in order to take various actions based on their contents.
The following code appears to read the NetworkStream fine but when I try to read the data into an array and output one field into a text file the code is only catching a few lines of the high number coming through the port.[code]....
change the program flow- so that it ignores certain precedures.Functionality: a form that displays all users. Optionally a user could check a check box and it would display his age. beside it Program Precedure: Now, I have to recheck everytime if it is checked. Is there a way to make the program just ignore a certain line of code(or something, that whatever it is I can't name). And I'm asking that the program should run without any evaluation whatsever?
View 7 RepliesSay if i have like this If a > -1 And MyArray(a)="hello" then End If If possible how can i change it so that iff a > -1 then check for second condition. Without using nested if's
View 2 RepliesI am using a two-dimensional array of 10 elements, but my code is extremely slow.
[code]...
I create a new empty array with every iteration of the for loop. Is there a way I can use the same array but just clear it instead?
How to declare two object in one statement for vb.net?
Example
If IsNumeric(TextBox1.Text),(TextBox2.Text) Then
lbl_answer.Text = Val(TextBox1.Text) + Val(TextBox2.Text)
Else
MsgBox("Error only number can be calculate")
End If
I can do
if isnumeric(textbox1.text) then
But I can't say
if isnumeric(textbox1.text), (textbox2.text)
How can I do so?
I need help with ASP.NET in the VB.NET language.Currently I have a server that contains a script called Query.aspx. I want this script to evaluate another script, as an example "Test.aspx", and print the evaluated response out as Query.aspx's response.
View 6 Replies"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...."
I have a string like this:Correct Strings Dim value As String = "45, 2111,56, 1, 9, 99, 62,"Invalid Strings:Dim value As String = "10.01, 12,, , "I need to evaluate this string that has this format indefinitely,The regex evaluate the commas who are in series and are only integers.
View 2 RepliesI'm trying to use a select case statement to evaluate the value being passed from an array list...any suggegstions. I need to determine if the array is null or not, and setup my select case statement based on if the array is populated. See sample code below Code Sample selected As New ArrayList
Dim dvExisting as DataView
Dim grdExisting as DataGrid
For
i = 0 To dvExisting.Count - 1
If grdExisting.IsSelected(i) Then
[Code]...
I have one text box that the user enters an integer into. I use a select case to determine what the length of the number is. (along w/ string.length, etc)based on how long it is, I can determine if the number is 1-9, 10-99, 100-999, etc. What I want to do next is, evaluate the number and display a roman numeral that matches.
intMyNumber.substring(1,?) ' 1 would return the leftmost number
if intMyNumber.substring(1,?) = 1 then
if intMyNumber.substring(2,?) = 1 then 'etc
[code]....