Having problem make last if an statement work in the code. the variables in the if statment are doubles but the ide keep telling i need a proceeding if statement. but is already there it is in the last if statement of the code
Public Class Form1
Dim Totals As New List(Of Double)
Private Sub btnclear_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles
[CODE].....................
I'm having this error trying to debugg a calculator:
I write:
"Private Sub cmdsumar_Click()"
And when try to debug it, it said: "Error Stament is not valid in a namespace"
I have a label that displays the result of a calculation, i.e lblTotalCost.Text = dTotalCost, where dTotalCost is a Double. When I try use FormatCurrenct(lblTotalCost.Text = dTotalCost), the program crashes and says unable to convert string to double.
View 2 RepliesI've got a heavily used web application that, for the first time in 2 years, failed doing an equality check on two doubles using the equality function a colleague said he'd also been using for years. The goal of the function I'm about to paste in here is to compare two double values to 4 digits of precision and return the comparison results. For the sake of illustration, my values are:
Dim double1 As Double = 0.14625000000000002 ' The result of a calculation
Dim double2 As Double = 0.14625 ' A value that was looked up in a DB
If I pass them into this function:
Public Shared Function AreEqual(ByVal double1 As Double, ByVal double2 As Double) As Boolean
Return (CType(double1 * 10000, Long) = CType(double2 * 10000, Long))
End Function
the comparison fails. After the multiplication and cast to Long, the comparison ends up being:
Return 1463 = 1462
I'm kind of answering my own question here, but I can see that double1 is within the precision of a double (17 digits) and the cast is working correctly. My first real question is: If I change the line above to the following, why does it work correctly (returns True)?
Return (CType(CType(double1, Decimal) * 10000, Long) = _
CType(CType(double2, Decimal) * 10000, Long))
Doesn't Decimal have even more precision, thus the cast to Long should still be 1463, and the comparison return False? I think I'm having a brain fart on this stuff...Secondly, if one were to change this function to make the comparison I'm looking for more accurate or less error prone, would you recommend changing it to something much simpler? For example:
Return (Math.Abs(double1 - double2) < 0.0001)
Would I be to try something like:
Return (double1.ToString("N5").Equals(double2.ToString("N5")))
I wonder, whats the proper, accepted way to convert doubles to strings? I've heard cstr(blah) is wrong (despite it working perfectly OK for me....), what is the proper way to do this say if I want to display the value of a double in a textbox (along with 'the answer is' or somesuch)?
View 1 RepliesI am tasked with the job of reading the X and Y coordinate of a Text label from a "save file" of a 2D CAD drawing. I found the exact position of the coordinates in the file, but I still don't understand how to read them 100%. They aren't simple ASCII characters.First, I read the file byte by byte, and load them into a textbox seperated by spaces as numbers from 0 to 255. Here is an example X and Y coordinate
View 1 RepliesI have a bunch of type Double variables in my program, say for example
Dim Area as Double = 0
Dim Perimeter as Double = 0
Somewhere in my program I want to calculate these values, so I define
Public Sub TheSquare(ByRef TheArea as Double, ByRef ThePerim as Double, ByVal TheSide as Double)
TheArea = TheSide^2
ThePerim = 4 * TheSide
End Sub
and somewhere in the program I'm collecting side lengths and calculating the area and perimeter; say
While True
S = GetSideValueFromSomewhere()
TheSquare(Area, Perimeter, S)
End
In my real program, I have, say, 20 quantities that I want to calculate. Obviously each one has a different equation. But in the end I want to output all 20 to a file, so to save typing, I create an array of the quantities, like this:
Dim TypingSaver() as Double = {Area, Perimeter}
so that I can dump values to file with a three-line for-loop instead of copying and pasting 20 variable names.
This does exactly what I want if Area and Perimeter were reference types like Objects. But since they are Doubles, TypingSaver contains only their values, not references to the actual variables. So after I use my TheSquare function the values of Area and Perimeter are correctly updated but TypingSaver just constains whatever the values of Area and Perimeter were when I declared the array.
how can I create an array of references to doubles in VB.NET?
I have a dataset (imported from a XML file) with double records (clientname), and I want only the records with the most recent date (datetime field) written to a SQL database. Now I sort the dataset ("clientname ASC, DateTime ASC"), so the newest entry is written to the database.
[Code]....
could anyone show me a code on how to transpose a two dimensional array of doubles (changing rows to columns and vice versa) ?
View 1 RepliesI have the following code in vb.net that calculates the amount before tax was applied:
Public Shared Function CalculateRateBeforeTax(ByVal rate As Decimal, ByVal tax As Decimal) As Decimal
Dim base As Decimal = rate / (1 + (tax / 100.0))
Return Math.Round(base,2)[code]....
I put the above scenarios into some unit tests using c# and using the nunit testing framework. The first scenario passes, but the other fails and I am not sure how I can get it to pass. Here is are my tests:
[TestFixture]
class TaxTests
{[code].....
As I said before, the first test passes, but the results of the other tests are:
Second Test expected 305.1600000000000003d But was: 305.1643192488263d
Third Test expected 95.54999999999997 But was: 95.55555555555555557d
the Threading.Interlocked class provides; I don't understand, though, why the Add function only offers two overloads: one for Integers, another for Longs. Why not Doubles, or any other numeric type for that matter?Clearly, the intended method for changing a Double is CompareExchange; I am GUESSING this is because modifying a Double is a more complex operation than modifying an Integer.
View 4 RepliesI need to define a property in my class which is an array (of doubles).My original (bad) version is this:
Public Class Market
Property Correlations0 As Double
Property Correlations1 As Double
Property Correlations2 As Double
[code].....
This however doesn't work. I get an error already at design time: "Public Property Correlations as Double has no parameters and its return type cannot be indexed."What should I do with it? I also do not know in advance how large the array should be (the array size is determined at runtime based on other properties).
I'm trying to create a Select Distinct query, but i'm getting stuck with either an empty combobox either a filled combobox that displays all the doubles.or a message "System. Data. DataViewManagerListItemTypeDescriptor".I have a form (form5) with 1 combobox and 1 datagrid. The datagrid loads 5 collumns "ID", "firm", "Fname", "mname", "Lname".[code]I would like to select the firm from a combobox and filter the datagrid so that it only displays the selected firm and the people that are registred here. Furthermore i want the combobox that i use for selecting the firms to lose the doubles.I can load the datagrid and load the Combobox, but selecting is only pointing to the record (highlights in the grid) i chooses but doesn't filter.[code]I use the "Me.EmployeesTableAdapter.Fill" method so mu question is, is it possible that i don't need to use the OLEDB connection or do i still need this to correctly connect to the DB (access)? I changed the script that i brewed together as displayed above, but this did not do the trick.
View 7 RepliesIs there a way to get the fraction parts of a Double without using string manipulations? Specifically in vb.net?
There are numerous examples for a decimal in various languages. One for vb.net is this one
Basically they all seem to use either a mod or Truncate method or they take advantage of casting to integer behavior. But none of those approaches will work for a double/float type due to the inherent inaccuracy of the double/float type. There is also the problem that doubles don't cast to decimals reliably. Below is a test case to show what I mean and expect.
<TestClass> _
Public Class BasicNumberTests
Function DecimalFractionalPart(ByVal number As Decimal) As Decimal
[Code]....
I have a main form that is set to be an MDI Container (IsMDIContainer - True). I have a number of child forms to that parent. When I first display a child (Maximized and .Dock= DockStyle.Fill) in the MDI Window, all is fine, but if I click the maximize button to bring the child down into the MDI window, then click the maximize button again to dock it again, the size of my menu in the main form doubles. I have that main menu setting "Allow Merge = False."
View 3 RepliesI wrote some software in Vb6 a long while ago and this program creates a datafile. This datafile stores variables like doubles, ints, arrays etc, using the Get/Put methods from VB6. This all worked great for vb6.I am now starting to rewrite this tool in .net and find that the binaryreader as well as the other fileopen methods do not convert the doubles correctly. So as I rewrite the software I still want to read the old datafiles just like before.if I use a byte array and read 8 bytes, the bytes read are identical in Vb6 and vb.net. We are talking about reading an existing old binary file created by vb6.
for example the number 3, stored as a double has a 8 byte array that looks like this:
[0][0][0][0][0][0][0][5] in vb6.
in vb.net if you use the bitconverter.getbytes(cdbl(3)) you get
[0][0][0][0][0][0][8]64]
in vb6 the first array is converted to the # 3 correctly.in vb.net the array is converted to something way way off.
I need to write values, mostly doubles into a text file in VB.NET. I ported the code from VB6, but the performance of the VB6 write#fileID, vars) in VB.NET, is very bad, it introduces a delay of about one hour. I have tried out the streamwrite, and its performance is good; it's actually faster than VB6 write.
I am using the write(string) method for the streamwriter, and I am concatenating the values using variable names as follows: streamwriter.write(var1 &","& var2 &","&....&","& var n &","). This version of write enables me to have more than one variable written to file per statement. The problem that I have is that the content of the file is incorrect, unlike the one produced by the slow VB6 write in VB.NET.
Is there a better way of achieving this requirement; preferably using the streamwriter? I cannot use the streamwriter.write(double), becuase I'll have to use multiple lines as I am writing about 800 vars in convergence test loops resulting in a total of just over 2 million writes.
The following works:
string connectionString = "Provider=Microsoft.Jet.OleDb.4.0;Data Source=" + str_excelFileOnLocalMachineInReports + ";";
connectionString += "Extended Properties=Excel 8.0;";
OleDbCommand myCommand = new OleDbCommand("Select * from [pFACTData$];");
[Code]..
But as soon as I change any of the numbers to doubles (e.g. 23.32457) I get a crash (it doesnt crash on the insert, it crashes on the next one:)The INSERT INTO statement contains the following unknown field name: '23#2345'. Make sure you have typed the name correctly, and try the operation again.
I am using an oleDb connection to connect to an excel spreadsheet (.xlsx) file and load the information into a datagridview. From there I hope to have it edited by a person and programmatically at runtime. However, I noticed that when I import a file that has integers in a column, it will not import any of the string values in that column. Also, It will not allow me to manually enter strings into that column at runtime - it results in an error stating: [Code]
View 16 Repliesi'm having some trouble with most likely the simplest of reg ex i'm trying to get thew contents of a form: <form action='I NEED TO RETRIEVE THIS DATA' id="questionaire" method="POST"> i need to retrieve the contents of the action which is between 2 ; (single quotes rather than doubles) i have:
Dim regexSource As New Regex("(?<=action=.*?"").*?(?="")", _
RegexOptions.IgnoreCase Or RegexOptions.Singleline)
Dim regexSourceMatches As MatchCollection = regexSource.Matches(HTMLResponse)
[code].....
i've to declare two constant arrays one bidemensional of strings the other bidimensional of Doubles?
View 10 RepliesintLoginTime = txtLoginTime.Text
intLogoutTime = txtLogoutTime.Text
[CODE]..........
The problem is that the numbers seem to round after the decimal point, so if I entered a login-time of 8.15 and log-out 9.30, instead of showing 1.15 as the difference, it shows '1'. is there a way around this?
I've been researching all over Google for how to Read/Write Floats, Doubles, Longs and String to memory. I believe I have the reading Longs, and Floats working properly. I'll post my Module (which contains all my Read/Writting).[code]
View 2 RepliesPublic Class Inventory_Edit
Private Sub Inventory_Edit_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
'TODO: This line of code loads data into the 'CategoryDataSet.Category' table. You can move, or remove it, as needed.
Me.CategoryTableAdapter.Fill(Me.CategoryDataSet.Category)
[URL]
I added an "edit" icon on my bindingNavigator. When users click on it, a new form will come out and pull out all the data records from the datagridview. Now the strange thing is that when I wanted to edit the data records, when I left the product name blank, I would get an error message saying "Product cannot be blank" - please see above code. But when I left the "Cost Price" blank(same applies to "Sell Price" and "Quantity"), the error message box wouldn't come out, instead, it did not allow me to move on to another textbox, close the form etc until I filled out that textbox with INTEGER. May I know why the error mesagebox would not come out when I entered the wrong datatype?
the testBoolean is set to the value True, but for some reason when debugging, it step through both conditions, so in the end the button1.visble becomes False, but I want it to be set to True.[code]....
View 14 RepliesI am very new to vb, I know there is an error somewhere, I had an assignment which stated that if a number was < 101 or > 500 and the answer is correct the output should be, for example-123, if the answer was wrong then the message output should be wrong number <101>500. Everytime I type in a number(no matter what the number) and click on my check button I get the output message. If at all possible, can you please assist. My professor gave the following example, but I am still not getting it:
Dim strInteger As String = "52.801"
Dim dblNumber As Double
dblNumber = CDbl(strInteger)
[code].....
I want to use a value that is pulled from the SQL within the if statement. Ideally i want to do the equivalent of <% If DataBinder.Eval(Container, "DataItem.BookID") == 1 Then%> Is there a way to do this with the correct syntax?
View 2 RepliesHow to combine these two conditions in one section
Private Sub DataGridView1_CellValidating(ByVal sender As Object, ByVal e As System.Windows.Forms.DataGridViewCellValidatingEventArgs) Handles DataGridView1.CellValidating
'condition 1
' check given value is numeric or charactr type
If e.ColumnIndex = 3 Then
If Not IsNumeric(e.FormattedValue) Then
DataGridView1.Rows(e.RowIndex).ErrorText = " must be a numeric value"
[Code] .....
'condition 2
' check given value is greater than 0 or not
If e.ColumnIndex = 3 Then
If (e.FormattedValue.ToString = "0") Then
[Code] .....
I have and existing .rdlc file where I display the grades of each students as well as the general average. I get general average like
=FormatNumber(Switch(Fields!YearLevel.Value="LC7" or
Fields!YearLevel.Value="LC8",(IIF(Fields!SectionName.Value<>"1st Sec A" and
Fields!SectionName.Value<>"2nd Sec A",
[code]....
I want to display:
"1st Honor" if gen. ave is >=90 but all the subject grades must be >=90 also
"2nd Honor" if gen. ave is >=88 but all the subject grades must be >=88 also
"Third Honor" if gen. ave is >=85 but all the subject grades must be >=85 also
How do I do it?
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?