I have a function that allows a user to enter numeric vallues and also a period for the decimal points but I also want to allow for users to enter the minus sign to allow users to enter negative values . How would I go about it.
Public Function SingleDecimal(ByVal sender As System.Object, ByVal eChar As Char) As Boolean
Dim chkstr As String = "0123456789."
[code]....
As the title says,I want to just have only numberic/decimal values accounted for, if it is negative or if anything else is entered into the textbox, how do I have a message display for that?
View 3 RepliesI am trying to make a sample Master-Detail relation ship database example in vb.net. When I add MasterTable a new row via bindingnavigator and save via savebutton autoincrement field goes -1 -2... negative values hence cannot get correct ID numbes saved in table rows till I close open sample application. How can I see correct autoincrement ID numbers in gridview after savebutton ?.Just ID numbers saved to mdb.but cannot see them i gridview and displaying negative weird numbers. This problem is important because without getting ID numbers cannot bind Detail table rows to newly recorded master table rows.
View 3 RepliesI am trying to create an input validation for my program to prevent the user from entering negative values. I've been using:
If (decLabor < 0) Or (decPartss < 0) Then
MessageBox.Show("Input prices for parts and labor must be positive")
I have a problem when i am passing negative value to "AddMinutes" function.The problem occurring when i subtract a value from the "00:xx:xx".[code]When it is trying to subtract, it is throwing the "Un-representable DateTime" error.How do I do the subtraction of minutes in this scanerio?
View 3 RepliesI am using a DataGridView that has a filtered dataset and I like to validate a column in a new or changed row via a sub in the partial dataset class so that I can set the errorprovider to an error if the entered value isn't unique.I started out to set the field in SQL server with a unique key and then catch the sqlerror on the form. But data validation is best practice to do in the partial dataset class so I am trying to do it for this particular problem aswell. But after spending a lot of time I am stuck and wonder if it is even possible to do this particular validation in the partial class?
View 9 RepliesI have a program that calculates values of a function, say f, with respect to another variable, say L.I have an array of f(L), for L going from 0 to a given integer value, say t-1 in steps of a value i.I need to export the values of this function to an Excel spreadsheet in a given column, and to do this, I would like to re-index the function f, since i is much less than one, and so the following loop I use (see below) won't work:
For L = 0 To t - 1 Step i
Sheet.Cells(L, 1) = L
Sheet.Cells(L + 1, 2) = f(L)
Next L
The first code in the loop will essentially load the values of L itself, at which the function is defined and calculated, and the next line will load the values of the function at each value of L.Since the indexes of the row and columns in an excel spreadsheet only go in steps of 1, I need to convert the indexes of the function, or the indexes to which L is loaded, so that it would be scaled so that the first entry corresponds to L=0, but the next is L=i, but loaded into row number 2, etc.
I have a gridview(editable).
It may have more than 1 row with columns startdate and enddate.
StartDate EndDate
4/4/09 6/6/09 (valid-existing row)
1/2/09 3/3/09 (valid-existing row)
7/7/09 9/9/09 (valid- edited row)
3/3/09 6/6/09 (Invalid - edited row )
When you see the above table/gridview, you will know what I want to validate.
I should be checking whether there is any row having start-end dates lying within the existing date range, if so I should invalidate them.
I shd have only distinct date range in my rows.
How do I do that.
May be Useful note: I will be able to check which column name I tried editing in that row.
Do any of you have some ideas how to create a logic to accomodate my validation issue in my webbased gridview control ?
I've made a temp converter and i'm looking to get some validation for it. I have looked online, but most do it in a way that i don't want.
I have 3 text box's, of which i only want numerical values and nothing else to be entered into the boxes. However, i would like the validation to run when a button is pressed (in this case, the calcualtion button). I would like a messagebox to pop up stating there is a non-numerical value entered into any of the boxes and for the calculation code to not run.
I'm creating an emulator for a device to simulate wave forms. My challenge is that when I try to convert the output of the following code, I can't convert the Math.Sin's double output into byte values that lend themselves to the byte array format required by an existing graphing control as listed at bottom below. I''m not sure how to handle this when the sin function creates negative values but the byte values will need to be positive and basically 'shifted up' so that anything over 127 is negative. (0 - 255) unsigned. BitConverter.GetBytes has been suggested but THIS is the result of that attempt.
[Code]....
I have a function that allows a user to enter numeric vallues and also a period for the decimal points but I also want to allow for users to enter the minus sign to allow users to enter negative values . How would I go about it.
Public Function SingleDecimal(ByVal sender As System.Object, ByVal eChar As Char) As Boolean
Dim chkstr As String = "0123456789."
If chkstr.IndexOf(eChar) > -1 OrElse eChar = vbBack Then
If eChar = "." Then
[Code]...
I am writing below code for validating compulsary field account no. in form.User's requirement is set focus back on field when error comes :
If txtAccountNo = "" Then
MessageBox.Show("Account no filed can't be left empty")
txtAccountNo.SetFocus
Exit Sub
End If
It's working properly. But suppose user don't want to fill form and exiting from application.Message box keep on appearing till user enters account no.
In C# we can declare a decimal number as negative zero i.e usingDecimal x = -0.0M we can define a variable x which holds value i.e negative zero. +ve zero can be differentiated from -ve zero using Decimal.GetBits method and looking at its MSB
View 4 RepliesI have an SQL Query that looks like this [code]I get two results. The first is the correct one which is -0.0060 and the second @return_value which is 0.This is also the case when I call the stored procedure from my code, I get a 0 back instead of the -0.0060 that I want. This is how I am calling the stored procedure from my code:[code]
View 3 RepliesI'm doing some math with the Timespans in .Net, and occasionally the sum results in a negative Timespan. When I display the result I am having trouble formatting it to include the negative indicator.
Dim ts as New Timespan(-10,0,0)
ts.ToString()
This will display "-10:00:00", which is good but I don't want to show the seconds so tried this.
ts.ToString("hh:mm")
This returns "10:00" and has dropped the "-" from the front which is the crux of the issue. My current solution is this:
If(ts < TimeSpan.Zero, "-", "") & ts.ToString("hh:mm")
but I was hoping to accomplish the same by using only the format string.
My program im working on does grayscale, builds an alpha mask, and splits the color channels.How do you invert a picture? the above are done looking at the image pixel by pixel.
Im using vb2005.net, for the sake of speed is there other ways of doing those things using drawing.graphics?
Quick Basic alllowed the use of negative array index's (ex. Dim points(-8000 to 8000). I am trying to convert this QB program to VB but it won't allow negative array index's. How can I create a negative index array in my VB code?
View 12 Repliesi have a negative number and i want to change it to its positive
eg -14 to 14
I am using delta plc. i want to send +1 to +30 & -1 to -30 numbers in 4 byte hex format(xxxx) in vb.net.
View 4 RepliesWhat do I use for the format number function to show a - for negative numbers instead of ()?
View 2 RepliesPublic Class Final2
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
[Code].....
there's a logic error in this code. it accepts negative value but output positive one. just wonder if Math.Abs functions here.
I have my VB.NET exam tomorrow and I have a list of potential questions, and there is this one question I really fail to find a good explanation for. it gives me this function:
Dim x, y as Single
y=2
y=x+10
MsgBox(x)
it returns 0... and I am supposed to explain what that happened. I have tried changing the numbers so it gives a positive number, and then it works properly... I have tried changing the type too, and still 0.
I need to check a value and make sure that it is not a negative number using a try catch statement I keep getting an error saying that I have to use a method.
Try
TotalCurrentBalance < 0
Catch ex As Exception
End Try
I wouldn't put a if statement would I? I am thinking that would defeat the purpose.
I need to convert a negative integer to a positive one.
View 14 RepliesIs there a built-in function in .NET (VB) to convert a negative number into a positive, and vice-versa?I usually end up just using:NegNum = PosNu - (PosNum * 2)PosNum = NegNum- (NegNum * 2)
View 6 RepliesI'm having problem in my datagridview.I'm using vb 2008 and an access database. When I create a new record for my item the No column (primary key and autonumber in access) always shows a negative number.How can I make that a positive number and it should follow the numbering in the datagridview.
View 3 RepliesWhy when I add new item in my database table it will show negative increment?
how can i change it to positive increment or use only integer increment.
I have written a code that when the click the calculation the button a inputbox pop up and you enter in the income and then you enter in the expense. [code]...
View 11 Repliesi have finished my code and the program works but i need setup a few error messages incase a user inputs invalid data (non numeric, and negative numbers)i keep getting both errors at the same time when i input a negative or non numeric data. My program allows a user to calculate cell phone bill
[Code]...
Similar in concept to Math.Abs() - I'm looking for a function that when given a positive integer will return the same integer. If given a negative, will return zero.
So:
f(3) = 3
f(0) = 0
f(-3) = 0
Yes, this is simple enough to write on my own but I'm wondering if the .NET Math class already has this built in or if the same can be achieved by cleverly chaining a few Math.* calls?