Is their a more elegant way to assign a space to a value, if a database call returns null for a data set column? I am doing the following check which is pretty tedious:
If (ds.Tables("employee").Rows(0).Item("txtNamePrefix").IsDBNull(0)) Then
txtNamePrefix.Text = ""
Else
txtNamePrefix.Text = ds.Tables("employee").Rows(0).Item("txtNamePrefix")
End If
I have some code which gets child items for a menu via the GetChildren function which takes a list of menuData: Dim builtMenu As New List(Of MenuData)(_rawData.FindAll(Function(item) item.GroupingID = 0))
For Each menuData As MenuData In builtMenu
If menuData.Children IsNot Nothing Then
menuData.Children.AddRange(GetChildren(menuData))
End If
Next
If I check if menudata.children isnot nothing, it always is nothing because the GetChildren function is yet to run (providing the child items, which do exist). If I remove this check and just have this code:
Dim builtMenu As New List(Of MenuData)(_rawData.FindAll(Function(item) item.GroupingID = 0))
For Each menuData As MenuData In builtMenu
menuData.Children.AddRange(GetChildren(menuData))
Next
Then I am presented with a Object reference not set to an instance of an object error on menuData.Children.AddRange(GetChildren(menuData))
I am trying to load an image onto a web form depending on the image's URL path inside a database. I can get this to work, however I am trying to display a dummy image incase the record in the database has no image and the column is NULL.
Below is the code that I imagined would work but I receive an error:
Conversion from type 'DBNull' to type 'String' is not valid.
'// Load Item Image in imgMenuItem Image Control //
If (Not IsDBNull(Rdr("img_url"))) Then
imgMenuItem.ImageUrl = Rdr("img_url")
[Code].....
I have a WPF application that uses a third-party library to perform a specific task; this library, in one of its methods, executes the statement Assembly.GetEntryAssembly(). If I run the WPF application on debug (by running a .Net exe for testing) the library works properly and Assembly.GetEntryAssembly() returns a reference to the assembly of the executable, but in production I have a different situation that causes me some problems.
[Code]....
I have the following code in my application. When it is executed it brings out a null value at times, where i am sure there should be a value returned. I have checked by running the sql statement in the database and it returns the correct value. What could be wrong with my code? [Code]
View 6 RepliesRather interesting bit on this one, I have all the code where it should be working but whenever it hits parse1 it returns the file as null. [code] I probably just need a fresh pair of eyes because I'm not seeing where this is glitching (...or if it's just my computer in this case.)Rather annoying at this point, tried break points and following the execution to catch the error but no such luck.
View 2 RepliesI have some VB.NET code that creates a TransactionScope instance:
LoggingUtility.LogDebug("UpdateCallTable", "SatComCallDataImporter", "About to associate call data with contracts")
Using ts = New TransactionScope()
LoggingUtility.LogDebug("UpdateCallTable", "SatComCallDataImporter", "Getting all unimported SatCom calls")
My application is throwing an exception on the call to the creation of a new TransactionScope, with "Object reference not set to an instance of an object.". The exception isn't thrown on my development machine or my test machine; only on the customers production machine, and I have no idea why. I've placed debug lines immediately before and after this line so I'm positive it is this line causing the problem.
A have used TransactionScopes throughout the application and this is the only place throwing the exception on the client machine."About to associate call data with contracts" gets written to the log and the next log entry is the "Object reference not set to an instance of an object".
Code works fine if I move it out of a transaction.I've been struggling with this for 4 days now and have got no closer.
i hav two openfilefialogs(1 and 2). So i also have a listbox. the files opened with the openfiledialogs will be added to the listbox. and when i need to open the files i need to see if they are from which openfiledialog. so
it is like this.
Path.GetDirectoryName(OpenFileDialog1.FileName) & "" & Form3.ListBox1.SelectedItem.ToString
'if this returns a null then go to this
Path.GetDirectoryName(OpenFileDialog2.FileName) & "" & Form3.ListBox1.SelectedItem.ToString
I have a DataGridView connected to a DataSet. I want to allow the user to update and insert new records on the RowLeave and CellLeave events. The Update method works:
Me.ExpensesTableAdapter.Update(Me.DataSet1.Expenses)
I am basically trying to access the CLSID portion of the registry... some CLSIDs are working, some arent...
Here is my code:
Dim regkey As RegistryKey
regkey = Registry.ClassesRoot.OpenSubKey("CLSID" & location & "InprocServer32", False) 'Just Returns null when im looking for a certain CLSID
Dim SubKeyvalues() As String = regkey.GetValueNames()
Dim subkeyvalue As String
subkeyvalue = regkey.GetValue(SubKeyvalues(0))
I'm converting a system of numerous programs from foxpro/foxweb/javascript to asp.net/vb/sql server.
I'm coding for a dropdownlist which is currently controlled via js.
I don't like using the control this particular way, but I want to maintain look and feel for the customer.
The control is initialized with some values via Page_Load() in behind code.[code]...
I'm trying to get data with the methods below and I get null response and can't figure out why. I'm just trying out a different way of using a wcf service from silverlight and I don't understand something that I should.[code]...
The employee object will stay null. If I put a break into the service call and follow through the code it finds the correct record from the database and the return statement shows an object with the correct data but still the employee object in silverlight side will remain null.
[Code]...
By my logic, this should only assign .length to index IF the length of strItem is longer than 0. This check is there in case the listbox is empty, or the user has not selected an item. However, everytime I go through this code without an item selected I get:
[Code]...
I have a several form elements that I am dynamically creating with javascript when a user changes a number value in a textbox, by filling the innerHTML of a div like so:
dfinnerhtml = dfinnerhtml + "<div class='field'> ";
dfinnerhtml = dfinnerhtml + "<textarea name='textbox1" + suffix + "' type='text' id='textbox1" + suffix + "' value='' rows='4' cols='20' class='field'></textarea> ";
dfinnerhtml = dfinnerhtml + "</div> ";
Then, in the aspx.vb code behind, when the user clicks the Save button, I run through a series of Requests to try and add the values that are in these form elements to a SQL string:
Dim DFTestValue1 As String DFTestValue1 = Request("textbox" & c.ToString)
where c is a loop counter to the # of textboxes created (the input value mentioned above that triggers the create) The problem here is that this code works in Internet Explorer but not in Firefox or Chrome. The Request() value returns null and nothing is saved. I hope I've explained this well enough.
I tried binding data to combobox at the runtime in the form load event. I had written the following bind function,
Private Sub BindComboBox()
Dim da As SqlDataAdapter
Dim conn As SqlConnection
Dim ds As DataSet = Nothing
[code]....
The problem is cboSubject.SelectedText is returning empty string.
I have a vb.net app that I can read a .xls file into a dataset or loop through as oledbdatareader and it gives the same result.Some of the rows have all nulls when I loop through them but if I open the same file in Microsoft Excel I can see that row fine.[code]From the info above the first two SKU values would come through fine but when I get to the 3rd row it would show a null.Is it possible that it kind of inherits the first rows type and since the 3rd row isn't all numeric if nulls it? [code]
View 1 RepliesI wrote a vb program that would prompt the user to enter a number and then enter the exponent value they wanted the number raised to. When they clicked button 3 it did the calculation. everything worked perfectly.
Now I need to change the program. I must create a function in a module and then call that function from button3 click event. I have tried several different ways and even though it seems to "work", it keeps returning an incorrect value![code]...
How can I call individual parts of this function? I would like to call return Gallons and decPaintCostperRoom as individual entities with a single function.
[Code]...
I have a select statement which was returning the required values but when I changed the OS date from English(US) to English(UK), it now returns null. I believe the problem is concerned with date since in the query am selecting values where the date from the database is the same as the date in a combobox but I don't know what else I can do. It almost looks like the dates in the combox and in the database are not the same and yet the date in the combobox is actually retrieved from the database and has been returning values fine until I changed the system date format.Here's my select command:
cmd4.CommandText = _
"SELECT sum(brought_qtty), recieved_qtty from brought_coffee, centre_weigh where brought_date=#" & _
dtComb.Text.Trim & "#" & _[code].......
I get an empty string when calling the .Text property. Refer below for snippet:[code]The internet search advises to use Items(col).Cells(2).FindControl(..), the problem with that is FindControl finds the control by ID, BoundColumn doesn't allow you to insert an ID for it.
View 1 RepliesI am using vb.net sqlite.net and dblinq0.20.1 to search a sqlite table on a primary key field.My code looks like this
Dim blb = (From d In db.Data Where d.UID = myuid Select d).Single
This returns the error "Coalesce used with type that cannot be null" .If I search on a nullable field it works fine.
I am making use of a 3rd party dll and am encountering some strange behavior in VB, which doesn't occur in C# Perhaps someone can explain what is going on. Anyhow, I am making use of a method in this 3rd party library which accepts an array parameter ByRef. The end result is the variable should remain null after the method call, but it is returning initialized for some reason.
[Code]...
Code:
Application.DoEvents()
Error:
[code].....
I connected to the Informix server using RazorSQL, created a stored procedure and tested it, getting the expected answer, so the procedure exists in the database in some form.
I then run the following code:
If ConnectToInformix() Then
Dim cmd As New IfxCommand("dc_routeHasOutstandingQuantity", conn)
cmd.CommandType = CommandType.StoredProcedure
[Code]....
This error does not occur when calling the stored procedure from a live SQL connection.
Ive created one database Sql Server Compact Edition 2005, with one table ("Cliente") I know that I can created my database good, but i have a problem saving information since three textbox, in my table(With columns "Nombre" "Apellido" "Cliente". In my form there is a button save ("Guardar"). When I do click in my button appear the next message : "The column cannot contain null values. [ Column name = Nombre,Table name = Cliente ] " and happen the same with apellido and Id_Cliente. And this happen becouse my code cant save the information....
This is the code
Option Explicit On
Option Strict On
Imports System
Imports System.IO
Imports System.Data
[CODE]...
And the code for my button is:
Private Sub cmdguardar_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmdguardar.Click
Dim myconnection As SqlCeConnection
Dim mycommand As SqlCeCommand
[CODE]...
I have a postgresql database, one table. This table has a date column too.And I have this code:
[code]...
The problem is, that the pgreader returns no rows (the parameters are right and the database contains the data too).firstday and lastday are f.e. '2005.05. 01.', the ConvertDate function converts the date to '2005-05-01' (the dates are storen in this form in the database)And when the commandtext="select * from arfolyamok where datum between '2005-05-01' and '2005-05-31'", then it works, the pgreader has the rows.Why? What make I wrong?
I want to add a null binary field in Database.[code]...
View 2 Repliesi have a combobox which get value from database through dataset. when i run the program n click on the combobox, the value is auto fill in with data from database. is there anyway to add a blank entries to the selection on the combobox??
View 5 RepliesI know I'm being an idiot here and I just can't work it out. But i'm trying to take some data back from a vb.net database. It's falling over with a Object reference not set to an instance of an object error. And before the code runs it's saying the variable is being used before it's set, but I can't see how. Code:
Private taNotifications As dsDataTableAdapters.NotificationsTableAdapter = New dsDataTableAdapters.NotificationsTableAdapter
Dim notification As dsData.NotificationsDataTable = taNotifications.GetDataByClientID(userrow.UserID)
If notification.Rows.Count > 0 Then
Dim notificationrow As dsData.NotificationsRow
Dim forwardURL As String = notificationrow.ForwardLocation
End If
It falls over on the Dim forwardURL As String = notificationrow.ForwardLocation
Considering that Grade.firstExam, Grade.secondExam, and Grade.finalExam are all TEXT and not numbers, i can't get the exact solution to convert null values into Zeros. I already tried to use NZ() but it returns an error message (Undefined Function 'NZ' in expression)im using VB.net with MS Access as my database. i also imported System.Data.OleDb Namespace.
[code]...
How can i convert empty string or null that exist in the field?