the combox is bound database table,but it is not displaying the contents of table in database,instead it is displaying corresponding null values(blank).it is showing just "select" and the blank spaces corresponding to the number of items in database
here is my
Function combobfill() As DataSet
addconnection.Open()
Dim selectstring As String = "select materialsname from materialtype_table"
[Code]....
I have a database that has null date values in it. When I call the columns from the database with the null datetime values and display it in the datetimepicker text box using a dataset, theres always values in the datetimepicker text box. It sets everything that was in the database with null values to the current date. This is what i have..
DateOPStartedRevisionDateTimePicker.Text = ds.Tables(0).Rows(0).Item(13).ToString
I just cant figure out a way to get the datetimepicker text box to display nothing if the values are null in the database.
the code display 2 colunms in one combo box from a table. i have table with 2 columns account_type and account_name. the account_type is an abbreviation(codes) which would be stored in a new table when selected. I want the code when the combo is click, would display the code-account_type and account_name in the same combo box.
Private Sub cboAccount_type_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cboAccount_type.SelectedIndexChanged
Dim cn As New SqlConnection(ConnectionString)
Dim query As String = "Select Concat(Account_type, ' - ', Account_Name) As AccountDesc, Account_type from Accounts"
[code]....
I bound datagridview to bindingsource. The bindingsource has its datasource a collection Called Rates which is a collection of Rate items. The rate object has a property called VALUE. I need the user to be able to edit different values for the collection; However, on the datagridview, i need to keep displaying on one column called OldValue the existing Rate value before the change while allowing the user to edit that value in a second column called NewValue.
In other terms, One colum OldValue will keep the existing values from the DB before being edited by the user, this column OldValue is readonly. Another column NewValue will display, the 1st time, the old value from the DB (similar to OldValue when we do the Fetch from the DB), but it`s editable column, so the user can modify each value in the column NewValue without overriding OldValue cells. For now, I bound both columns OldValue and NewValue to the same property VALUE of the Rate object,
[Code]...
I have two combobox on which will display company and department names. There is a"SelectedIndexChanged" event for company combobox. I don not want that is triggered when value of combobox are empty or null. I tried CompanyCombobox.seletedValue is not null and other ways, but they were not working. How do I detect there is empty or null value on combobox?
View 3 RepliesI need to use an array at any part of the project. It has been suggested to me to build an array and show its result in a combobox. Instead of having an input textbox, i will have a combobox which will display 10 common names which are kept in the array.
'Defines the array Names
Dim names(9) As String
'Defines the array's fields[code]......
i am making a safari booking system, and i have a combo box list(contains a list of hotels) how do display the prices of the hotels in a text box
View 1 RepliesI have a combobox that has filter items in it:
Me.cmbFilter.DataSource = (From f In files _
Let extension = "*" & Path.GetExtension(f) _
Order By extension _
Select extension Distinct).ToArray()
Displays OK in Vista - doesn't in XP
I'm trying to display some data in my combobox, the strange thing is that the combobox displays all data that has 4 four columns (I only want to display 3 columns out the four) but its not displaying rows that only have three columns?
For example
Text File
Column1, Column2, Column3, Column4
I only want to display columns 1, 3 and 4 so I use the following coding
For Each Line As String In System.IO.File.ReadAllLines(Path)
If String.IsNullOrEmpty(Line) Then Continue For
Dim Columns() As String = Line.Split(New Char() {" "c}, StringSplitOptions.RemoveEmptyEntries)
If Columns.Count < 4 Then Continue For
Combobox1.Items.Add(Columns(0) & " " & Columns(2) & " " & Columns(3))
Next Line
But some of the rows only have
Column1, Column2 and Column3
Again I only want to display column1 and column3.
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.
[Code]...
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:
[Code]....
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(",")
[Code]...
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
[code].....
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 RepliesI have filled a DVG with information and added another column to index(8) pragmatically Now i want to create a combobox with values depending on values in other cells on the same row so each row will have a combo box with different selections. below i have placed the code and hoped someone would have some input on how to approach this. i have tried datagridviewcolumn but that fills every row with the same information regaurdless of a if statement
[Code]...
i have a dice program that will find the random numbers according to user input as regards dice and throws required. My problem is when i have to display all the values in a listbox but in a horizontal type, were if a value came out more than once it displays the number and a bar for each time it come out and also at the end show the count of the times the number came out, to have a better idea the final chart needs to be displayed in the following format in a listbox as in the long run the program needs to run in a web application, but i am writing and testing in a window form application, then i will transfer to web application and use session variables and timers to control the output and the graph.
3 ||||||||| - 9
5 ||| - 3
6 ||||||- 6
10 ||||||||| - 9
2 | - 1
My code till now is that i have a class were a roll dice method and a similar values method are kept and from the form in the roll button these two methods are called and the results are shown in two listboxes one for how the roll dice random numbers with duplicates is shown and the other listbox displays only the numbers without duplicates.Also another method for the graph is in the class clsNDie but it seems that i have something wrong it this area?
i have a loop that does a simple math function and i need all the values to show up in a single message box. I've got it to when i get individual values minus the start value to show up in separate message boxes but i cant figure out how to consolidate can someone ?
View 1 RepliesCan someone tell me on how could I display the data from my SQL to a ListView? I only have one column to display.
View 11 RepliesHow do I display the actual values at the end of the bar graph so the use can easily see the real values?
I am using Microsoft Report Viewer in VB 2008.
I'm using vb.net and sql server 2000 for developing my application....The problem i'm having is the Null Reference Exception on the Following line of code:
Dim cmd5 As New SqlCommand("select crtns_removed, pieces_removed, scheme from Outgoing_Invoice where invoice_no = '" & Me.ComboBox5.SelectedItem.ToString.Trim & "' And category = '" & Me.ComboBox1.SelectedItem.ToString.Trim & "' and item_name = '" &
[code].....
I have a combobox with a dropdownstyle of dropdownlist (style 2). When a user finishes making entries and clears the form, I want the display value of this to return to null. With an unrestricted combobox, I could just set .text="" and be good to go; that doesn't work with the ones that are restricted.
View 3 RepliesThe Combo-box only has three items (Top View, From South looking North, From West looking East). Bound data from an Access Query called qryViewsFilteredByJob. I'm using it to pass a parameter to the filter for a binding source on a second query called qryAllSections2 (I don't think that's important though.)
When the form loads up it displays correctly stating on 'Top View', and I can click another other item just fine. When I pick another item, however, the first item, 'Top View', disappears and it replaced by whatever item I just clicked. So if I clicked 'From South looking North', the three item choices are now 'From South looking North', 'From West looking East', and 'From South looking North' again...
Some tables I am dealing with have null values and are throwing errors. So far ive tried a few solutions to deal with the nulls with no success.Here are the code samples from my efforts so far;
If (r("datemodified").Equals(DBNull.Value)) Then
datemodified = String.Empty
Else[code]....
i have ran the query and it is working ok (i.e all the cols exist)