.net - Have Double->float Conversion Regarded As "widening"?
Jan 22, 2011
Is there any way to tell vb.net (2010) to allow expressions of type Double to be passed to parameters expecting Float, without having to use an explicit CSng() calls, other than by turning off all complaints related to narrowing conversions? Given that a Double->Single conversion will never throw an exception, and given that precision loss does not seem to be a criterion for regarding a conversion as "Narrowing" (Long->Double is considered "Widening" despite the fact that it involves an inexact conversion from an "exact-value" type to an "approximate-value" type; a Double->Single conversion merely goes from an "approximate-value" type to a "somewhat-more-approximate-value" type, so it is in some sense less lossy).I know turning off Option Strict would eliminate squawks about Double->Single conversion, but that is incredibly massively overkill. Is there any way to stifle all complaints about Double->Single, without stifling other possibly-useful squawks?
Edit:If Microsoft isn't going to allow code to be written in the most logical fashion, would it be preferable to litter the code with CSng() every time I call graphics methods, or define NewRectF and NewPointF methods which accept doubles and then use the RectF/PointF overloads for the graphics methods?
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Apr 5, 2009
When I read a value from text box I want to make sure user has entered a number(int/float/double etc.) not a string. Is there any function to check it? otherwise how do i validate it.
Language : VB.NET
Version : Visual Studio 2005
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Apr 8, 2009
a user will enter a number, n, which ranges from 1 to 30. they will also enter a "P" or an "S" (sum or product). depending on which was selected, it will calculate the sum or product of the numbers from 1 to n.i'm having a conversion error on line 5 stating "Conversion from string "S" to type 'Double' is not valid." [code]
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Apr 12, 2011
I've been just making random programs trying to get the hang of the new language this time I was making a leap frog game where it switches back and forth beetween frogs every time a button is pressed. It also checks if the frog can land in the text box above the button pressed, if there is another frog there a message box will pop up saying sorry space is filled other wise the frog should land there.
[code]...
The error message says "Conversion from string "frog1" to type 'Double' is not valid." I understand what a double is but I've tried And If and that causes a bunch of errors.My Question is whats wrong with this cod and how can I make a double if statement???PS I did try to make an array to shorten this but thats in a different fourm will post URL later
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Oct 20, 2011
I'm reading Lat + Lng coordinates form my database. I need to convert them to double. This is what happens:
Dim strLat As Double = CDbl(reader.Item("lat").ToString) MsgBox(strLat.ToString) ' << result: 5237861 should be: 52.37861. The point is removed.
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Jul 30, 2011
I want to convert the string value "13.3939" into a Double yet when I tried Convert.ToDouble("13.3939"), Double.Parse("13.3939") and CDbl("13.3939") they all returned 133939.0. Does anyone know how to do this properly?
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May 27, 2010
Here's my code, it works but its not elegant --- can this be improved? The final multiplication is done for the Analog to Digital conversion (weight of the LSB).
Public
Class Form1
Private
Sub Button1_Click(ByVal
sender As System.Object,
[Code] ......
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Dec 10, 2009
I have a form to calculate charges based on input data and charges stored in an array. When I try to save an entry to a file my program crashes and I get the error "Conversion from string "" to type 'Double' is not valid.
If rdoDay.Checked = True Then
Quote.DrivingHrs = txtDrivingHours.Text
Quote.WaitingCount = txtWaiting.Text
[Code].....
The error highlights the last line of the if statement beginning "Quote.TripCost" as the error, but I don't understand why..
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Jun 9, 2011
So, yes, I've tried with these three formats, and the problem remains the same:I have a string, "s"For Each s As String In stringarray and this array is recieving data from a streamreader that is reading a csv file. The data I'm having dificulty reading are these very specific numbers(yes, only these numbers, because phone numbers get home safe and sound).The numbers I'm talking about are usually decimal.ValueList.Add(Convert.ToDecimal(s))
Now, when I convert them like that, they always bring a "D" alongside with them. I've personally checked the string multiple times, and it just has a "1", and somehow, my list recieves "1D" as a number, same thing happens with decimal numbers(0.29D for example). I've tried with Doubles and Integers, the result is the same.
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Feb 11, 2009
I am writing a program that asks the user for their name and the number of pieces they completed. The employees are paid more depending on the amount of pieces they have completed(i.e. <200 = .50 per piece, 200 to 399 = .55 per piece, etc.). I have to display the amount earned when the user enters the info and hits the calculate button. I have to use Select Case.
I was thinking this would be an easy program but I keep getting an error for each Case saying "Option Strict On disallows implicit conversions from 'Double' to 'Decimal'. I don't understand why it thinks it is a double. It says I can correct this problem by adding "Cdec" before each equation(i.e.
[Code]...
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Jun 13, 2011
[Code]...
The code compiles and seems to run correctly, but is underlined with the message "Implicit Conversion from 'Double' to 'Single'" Why would this be an implicit conversion if each of the variables is cast as a Single? Is this something I should worry about or change?
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Oct 7, 2011
I'm quite a newbie in VB.NET (and VB on the whole). So my question could sound rather odd, but still. I've stumbled upon an issue with the CInt and converting a double to an integer.
The issue is the following: CInt(10.5) would be 10
CInt(10.51) would be 11, but I expected 10... (Got used to C# style conversion: (int)10.51 would be 10)
As pointed out here Integer.Parse VS. CInt the result is just rounded in some fashion. Nowever, all I need is to get only integer part and throw away the fractional one. How can I achieve such type of conversion in VB.NET? After a short research I assume that I can use Fix() funciton to do the trick, but is it the best choice ever?
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Mar 1, 2011
I'm having an issue with 'access levels' The database is connected and my user levels are set up, Admin and User, I'm trying to set up so when you log in it checks if the username falls under an admin in the database. but I seem to be getting this Conversion from string "Admin" to type 'Double' is not valid error, [code]
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Mar 4, 2009
I have this program i have to do for my Intro class. The assignment is to have the user enter a pay code(A,B or C) and the amount of hours worked. If the hours is more than 40hrs, they will receive time 1/2. And it must also calculate a 22% Tax.I was getting this error: Conversion from string to type 'double' is not valid. But some how i eliminated it.[code]
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Oct 16, 2011
i always got error every time i run this program . here's the code.
'declaring variables
Const DEPOSIT As Double = 30
Dim dbltotal As Double
[Code]....
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Feb 8, 2010
I am trying to update MS-Access database where one field is boolean and updating a string. I am getting a error message "Conversion from string "Update Claims set appointed=" to type double is not valid".
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Mar 11, 2009
I'm getting this run time error using VB 2008 Express:
"Conversion from string "" to type 'Double' is not valid."
Below is my coding
If cmbxitem.Text = "Brownish" Then
TextBox2.Text = 37
ElseIf cmbxitem.Text = "White Feathers" Then
TextBox2.Text = 30
'ElseIf cmbxitem.Text = "B/Wchicken" Then
'TextBox2.Text = 15
[Code] .....
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Apr 27, 2010
Imports System.Math
Public
Class Form1
'Declaration
Public
NotInheritable
Class Convert
[Code] .....
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Oct 2, 2011
I am doing a project entitled "Automation of Student admission process".I am having a datafield UGPercent of datatype(18,3) NULL in my database.When i tried to insert it using the following code Insert into Markdetail(UGPercent)values(" & txtperc2.Text & ")..It shows me the error:conversion from string to double is not valid.what is wrong in my code?
here: Markdetail is my table
txtperc2.Text-The textbox used to get the UG percentage.
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Dec 4, 2009
I have code that loops through a string array to add words one at a time to a line of limited length. I am trying to fit a phrase on up to four lines, centering the words on each line. My code appears to add the first word but on the 2nd word I get a "conversion from string "IS" to type 'Double' is not valid" error.
Here is my code so far:
varResult = Split(strPhrase)
intWordCnt = UBound(varResult) 'count words in phrase
'make words fit on one line
[Code]....
The phrase in strPhrase is "GOD IS LOVE"
I don't understand why I am getting this error when I didn't on the first loop through the code and it Put the word "GOD" into the line.
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Jul 25, 2011
I have written this code and tried running it but I am getting errors in the code segments below. The error says "conversion from string to double is invalid". whereas the calculation for 'y' is an addition so should not be giving the value it is giving at the moment. ICCPtotcircuitres is also returning 'nothing'.
Private Function iccptotcircuitres(ByVal x As String, ByVal y As String, ByVal z As String) As String
Dim Res As String
Res = x + y + z
iccptotcircuitres = Res
[code]....
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Aug 13, 2009
while am executing the following code cmdSSN1.CommandText = "SELECT * FROM Patients WHERE SSN='" & Trim(txtSSN.Text) & "' AND id " <> EditPatientId
it shows 'Conversion from string "SELECT * FROM Patients WHERE SSN" to type 'Double' is not valid.
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Nov 2, 2010
I keep getting this error "InvalidCastException: Conversion from string to type 'Double' is not valid." whenever I try and run this piece of code. Could someone explain to me where it is trying to make a conversion to double? No matter what I do to my input string, I get the error.Here is the stack trace:
Input string was not in a correct format.Description:An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.
Exception Details: System.FormatException: Input string was not in a correct format.
[code]...
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Aug 25, 2009
I have a PictureBox, some TextBoxes and a 'generate' button.
code:
I want to create an 'Image Generation' Program with a little help from YugiohCartMaker.net, and when i try to generate, this error appears...
Conversion from string [url] to type 'Double' is not valid.
Also a question... why does it stop with "/y" and not with "/ycmaker/createcard.php?name="?
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Sep 15, 2011
I am currently in programming class and I have tried time and time again to complete a form called "theater revenue" that was assigned to me. Even though I have typed in a lot of code, it keeps telling me "Conversion from string "" to type 'Double' is not valid."
These are the directions: "A movie theater only keeps a percentage of the revenue earned from tiecket sales. The remainder goes to the movie company. Create an application that calculates and displays the following figures for one nights box office business at a theater. Assume the theater keeps 20% of its box office receipts. Use a named constant in your code to represent percentage."
Here is my code....
vb.net
Private Sub btnCalculate_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnCalculate.Click
' Declare variables for the calculations.
Dim dblATS1 As Double
' Gross Adult Ticket Sales as Double
[Code] ......
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Apr 26, 2012
[code]I'm trying to leave the textboxes A, B and C EMPTY so an error message box will appear saying "You did not put any value in textboxes A" or "B" "C".. but my program works if you put a value in the three boxes.[code]
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Sep 1, 2011
I have a form, which holds several comboboxes, textboxes, checkboxes.I use an msaccess database to store the values into.When I enter text in a textbox and then click the save button I get the following error:conversion from string "" to type 'double' is not valid.But I really don't understand, the field of the database where the textbox text is being stored in is a text type.I searched google for it and the problem seems to be that the type of data from the textbox isn't the same as entered into the field of the database.But the strange thing is, is that as far as I can see, it is.[code]
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Apr 27, 2010
I get an Invalid Cast Exception - Conversion from string to double not allowed. I don't know what to do.
Option
Strict
On[code]......
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Jun 25, 2011
I wanna perform a function like this. When you save a record, I need the primary key of that record to be auto-generated (X001). Say, when you create a new record and save it, it should be saved like X002 automatically.So to test this before I implement that on this project I'm working on, I created this little program.form.png
All its supposed to do is, when you click on the OK button it shows a code that is fetched from a database table. (X001). Then when you click on it ober and over again. The number should increase. X002, X003, X004... so on.Here's my code
Imports System.Data.SqlClient
Public Class Form1
Private Sub btnOK_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnOK.Click[code]....
But when I run it, it throws this conversion error.exception error.png.I know its pretty straight forward so I tried to correct it with what I know
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Mar 30, 2011
I have a application that writes and reads from a serial port.The com-port is opened elsewhere in the early stages of starting / running frm_Main and is not shown. I have a button1 on my form and when I click it, the module 'RTUValues_Get_IOData' executes perfectly ok, with no errors.[code]However when I call it via a thread [button2], I get the following exception error and it hangs, at the part shown above in RED"Conversion from string "" to type 'Double' is not valid."
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