i have a list of value contains null values and digit value
i want find max value from list but I do not know what with null value
I do not want to use null values in compare
how to how to computes the maximum value in a list contains null values and digit value in vb.net?
I load a list from a database like the example below. The class has more properties that the database table holds so when I load the list from the DB, there are Null values for certain properties of each item in the list. When I try List = List.Distinct.ToList, it never works (when null values are present).
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I'm using Visual Studio and table adapters using an Access DB as the backend. I need the minimum 4 digit value. I want to get next available 4 or 5 digit number. And this will change depending upon the users request. Currently I use a table adabpter query. But how would I write a query. I suppose I could do a long iterative loop through all values until I see a 4 digit.But I'm trying to think of something more efficient.
Function GetNextAvailableNumber(NumofDigits) as Long
'SQL Code Here ----
'Query Number Table
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I just finished this application where you enter a five-digit credit card number, with the fifth digit being the check digit. everything seems to work except, I can't seem to get it to determine that any number is "valid". Every 5-digit combination that I enter returns "The credit card number is not valid". Im using visual basic 2008 express
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I'm trying to check whether values ar between a maximum and a minimum limit. I do that 21 times, and it works 20 times. In case of the 21. time VB tells me that 15 is less than 8. Here the relevant lines of
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I want to set minValue and maxValue of text boxes to define a range of acceptable values for validation purposes.In VB 6 this is straight forward and can be done under text box properties, however in visual studio vb .net 2010 this is not the case or it may be the case that i am missing something.
View 4 RepliesI'm supposed to write a program that validates an inputted ten digit ISBN number using the check-digit at the end to ensure that the sum is a multiple of eleven. Before calculating this and detecting if the entered number is indeed a valid ISBN, we're required to check the first nine digits and see if they are indeed integers. After this the tenth digit is checked to see if it is "X" (for ten) or 0-9.
With the code I've written it keeps returning false for whether or not the ISBN is valid, even with valid numbers. I feel like its something to do with the hyphens; have I misused the replace function?I'm a little lost on how to make my code work, but I'm fairly certain my logic is okay so far.
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I feel there must be a single line, more elegant way to find the highest page number in my list of report pages. The code below works fine but seems verbose. Is there a better way?
Dim numofpages As Integer = 0
For Each reportrow In reportlist
If reportrow.reportpage > numofpages Then numofpages = reportrow.reportpage
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what the maximum and minimum values are for a Framework 4.0 System.Numerics.BigInteger
2 ^ x
or is it a
( 2 ^ x ) - 1 value?
I'm trying to figure out a good way of implementing a List(Of) that holds a maximum number of records.
I have a List(Of Int32) - it's being populated every 2 seconds with a new Int32 item.
I want to store only the most current 2000 items.How can I make the list hold a maximum of 2000 items, then when the 2001'th item is attempted to be added, the List drops the 2000'th item (resulting in the current total being 1999).
Thing is, I need to make sure I'm dropping only the oldest item and adding a new item into the List.
Is there a limit to the maximum amount a List(Of T) can hold? I need to know because I have a program that could potentially wind up in a really large loop that would add over 200 or so items to a list at one time.
MSDN search didn't really tell me much, but I'm in a rush at the moment, and was just wondering.
I'm making a project that randomly picks a number from an array, but if it picks a number less than 10 then the number is a single instead of a double.
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Dim N(2) As Integer
N(0) = "0" & 1
N(1) = "0" & 2
N(2) = "0" & 3
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Ok, I have like this:
Public basic_numbers(10) As Integer
basic_numbers(0) = 0
basic_numbers(1) = 1
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Easter day is determined based on astronomical events. Is there a "date" function or something similar that can be used in Visual Basic programming to project such a day?
View 4 RepliesI have to create an app that computes the amount income tax that a person has to pay, depending on salary. Income tax should be calculated for each portion of income in each range. Here are the following income ranges and taxe rates:
Not over $7825=10%income tax
$7825-31852 = 15%income tax
$31851-77100 = 25%income tax
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i keep getting zeros.
Im trying to write a program that will do:
1.The average of the four numbers. This answer will be placed into a text box reserved for that value. This text box cannot be changed by the user.
2.The maximum and minimum values. These will be denoted by changing the color of the largest number green and the smallest number red.
3.The range of the numbers. The range is defined as the difference between the largest and smallest numbers. The range will be placed into its own text box, labeled as such. This text box cannot be changed by the user."
Im using visual studio 2008 and it has to be written in VB
i want a button to perform a function of checking the last digit number in a field of a table in and add a digit to it and display it in a textbox.
View 1 RepliesI recently upgraded a project from 2003 to 2005, and there were errors in them, but I am unable to view any in the error list. Only one error displays in the list
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I've come across an error I'm not quite sure how to get rid of, I've got a listview with listview items making up the grid, I've got values coming from a database populating the cells however if there are any null values(in this case, there's null values in the date) it crashes my program. I'm not quite sure of a way to allow the listview to have null values in it, I figured it would default allow it but that's not the case.[code]....
View 1 Replieswhat is the code for allowing null values to appear on the textbox
Dim i As Integer
dg1.DataSource = bs
i = dg1.CurrentRow.Index
Patient_Profile.Txtpatient_id.Text = dg1.Item(0, i).Value
I have a databound DataGridView and use a button to control updates.
The problem is that if a db Column does not allow a null value an error is thrown ("Column <ID> does not allow null values") and then the datagridview automatically removes the row. This error is raised as soon as the user leaves the cell and before the update command is issued.
I doing a project for my office. In that I am showing the values and strings from a particular table based on the date range and vendor selection. It is working fine with the date range. Except within the date range if the particular reader has no data it throws an error message like dbnull string.
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I have an SQL query that gets a max value so that I can decide the next value to use in an ID field. The code works fine when there's a matching result, but if the query returns Null, it throws a Specified Cast is Invalid error.This is the code I'm using:
LastID = DirectCast(SQLQuery.ExecuteScalar(), Integer)
What would be the proper way to check for a null value?
I suspect this is going to be one of those cases where within 2 minutes of posting myquestion, I finally hit upon the right combination of terms in Google to find what I'm looking for...
I'm trying to import my xls files to sql server, but i saw some values become null even though data in excel values are exist.
below is my connection string :
Code:
Dim cnstr As String = "Provider=Microsoft.Jet.OLEDB.4.0;" & _
"Data Source=" & txtfName.Text & ";" & _
"Extended Properties =""Excel 8.0;HDR=YES;IMEX=1"""[code].....
This error occurs while i'm importing the alphanumeric values into text, but previous values are numeric (but string datatyped).
I have a bunch of tables who share the same kind of information, but each table has a different name for each. (There was no standardization on the naming scheme). Some tables have important data that others do not contain. Some tables that have shared important data, but they are null values. I'm writing a program to combine all the tables into one master table.
The problem is when I read in a field, the reader.getvalue(i) is null, and I cannot use that value to insert into my new master table, obviously. The null values are so random, and I cannot write IF THEN statements for every single field for every single table in the database. I'd have thousands of lines of code constantly checking for nulls, and then trying to figure out what to do with them. What can I do to convert these reader values from NULL into something VB/SQL can handle? ere is the code so you can get a picture of how I'm approaching this problem:
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So I'm writing a simple piece of code to take a series of strings, go through them, and replace and add values as needed, and then dump them all out to a text box. However, when I run the code I'm getting 3 null characters at the end of each line except for the last one. What am I doing wrong?
Code:
If isPet.Checked = False Then
While intI <> lenCode
Try
lineHold = codeHold(intI).Split(",")
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Have read most of the null value posts here, and I have managed to get things working as far as a "next record" button for my database application form (there's some awesome advice on this forum!). I have just one question, though. How do you manage saving of blank text box values from a form? I am using JET, but when I try to save an updated file that has a null value, it is not letting me. I got around it by forcing the text boxes with null values to contain " ", but obviously this is not the bext solution!
View 1 RepliesI have the followin problem. Opening a table using SqlDataAdapter, numeric columns(sqlDbType = int16, 32, 64) that allow Null value, are set in my dataRows to 0.I am using Visual Studio 2010 and Sql Server 2008.Here's my code:
Dim cmd As New SqlCommand
Dim ds As New DataSet
Dim dt As DataTable
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I'm confused at the variety of different ways to say "null" in VB.net. I've got text and numerical fields with checkboxes to mark unknown values; I just want to populate a table with the fields' values (if the corresponding checkbox is not checked) or null values (if checked) so I can later input them into a mySQL database.So my question is just which of the various null types I should be using in what situations.
View 6 RepliesI have a dataset which I wish to export to XML. The writeXML function works fine, but if a value in my dataset is a NULL, it doesn't export that element at all, for that row. I would have expected it to export at least an open and closed element.
View 4 Replies