I 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'm afraid that this is a stupid question, but i must assume that i have programmed VB.Net too long and now can't figure out how to convert this C# null coalescing operator into VB.Net:
if( Convert.ToBoolean(ViewState[tp.UniqueID + "_Display"] ?? true) == false ){}
I know the IIF-Function but i'm not sure how to use it here and if it gives the correct result(in IIF both expressions are being evaluated). Please help to shed light on the dark.EDIT: if you want to see the source of this: forums.asp.net There you can see a solution that generates a Option Strict On disallows implicit conversions from 'Object' to 'Boolean' compiler exception.
I have a class Customer which contains the property Extensions which in turn contains the property Any. I tried to do: Dim room = If(customer.Extensions.Any.ElementAt(0).InnerText, Nothing) but it threw an error when it did not find an Extension element in the incoming xml. I thought it would return nothing once it saw that the first expression was Nothing. Do I have to do a multiple if statement in this case?
View 1 RepliesI 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))
So I'm writing a query as follows:
Dim assSummary = From a In db.Assignments
Join ur In db.UserRegions
On a.Origin.ID Equals ur.Region.ID
[code]....
In the controller I can return the data easily as follows:
For Each c In assSummary
MsgBox(c.Description & " " & c.AssCount)
Next
If I pass the object through to the view using Viewdata("assSummary") = assSummary, how do I display the data? Every method I've tried results in messages about 'VB$AnonymousType_7(Of Integer,String) and I don't know how to retrieve the data from the anonymous type.
What are NULL values? Sometimes when I try to assign a query to variable, I get error saying:
Type-Cast-Error. txtMiddleName.Text = Reader.GetString(2)
How can I put it that if the value of the Middle is nothing then txtMiddleName.Text = "". Working on VS 2010 (VB.net) EDIT 1: This is the error Message I get (Line 364 is the above mentioned code)
Code:
Application.DoEvents()
Error:
[code].....
I have searched for two weeks, every night, exhaustively reading forum threads and trying all suggested solutions no matter how outlandish. Just as is the case with the many many forum threads about this same issue, the site works fine on my development machine. It deploys with no errors. It works from the production server and reads data from the database, but when it attempts to access a profile it crashes with this error.
A number of posts say to check or uncheck an option called "remove app_code.compiled file" but apparently this was a Visual Studio 2005 option. It is nowhere to be found in Visual Studio 2010. A number of posts say to make sure the App_Code.dll is present in my bin directory. It is present. I've deleted the app_code.compile file manually to see if that made any difference. I've changed the target framework from 4.0 to 2.0 and 3.5. I've completely deleted the site in IIS, created a different folder with a different name and redeployed the site with every combination of "allow this precompiled site to be updatable" and "Use fixed naming and single page assemblies".
i've included references to System.Web.Profile and System.Web and System.Web.Profile.ProfileCommon. I've created a new, fresh website targeting .net framework v4.0 and copied that web.config file to my application and recreated my profile entries to ensure that I didn't jack anything up in the config file along the way.
I'm using VS2010, vb.net, .net framework 4.0, and SQL Server 2008 Express on Windows 7 Pro with all updates installed. I have developed a website that uses memberships, profiles, and roles. I allowed the built in providers to create the aspnetdb.mdf file for me in the App_Data folder. I added a number of my own tables to aspnetdb.mdf so I would have a single database for all my site's data.
I am hosting the site on my own server. It uses Windows 2003 Server, IIS 6, SQL 2008 Express, and all of my software including the OS is up to date with the the latest servicepacks, updates, and all of the .net framework updates including 4.0. There are no updates left to install and I'm sure that my issue isn't due to a missing update or framework version.
I copied the aspnetdb.mdf and .ldf files from my app_code folder to the sql server express folder on my server and attached the database. I do this because I don't want the file to autoattach, because I will likely use a commercial hosting service in the future. I added a sql server user with ownership rights to the DB. strong text
I then modified my connection string in web.config to point to the UNC of my SQL Instance on my server and to authenticate with the sql server username and password that I set up with ownership rights to that database. I updated my membership, role, and profile providers in my web.config file to use the new sql connectionstring and I was sure to include the application="/" setting and to use before each provider.
I can run the site just fine from my development machine. I can log on to it and use all of its features. However, when I publish the site to my server I can access the site, both locally over my intranet and over the internet. I can navigate around on it and it retrieves all of the data from the tables that I added to the database myself, but when I try to log on to it or to create a new account (basically anything that uses memberships, roles, or profiles) the site crashes with the error and all of the data below.
I've checked to verify that the application name in my aspnetdb database is in fact simply "/". I've ensured that I'm running from an application pool that is using the 4.0 framework. Much of the googling and reading that I've done seems to indicate a problem with my providers, but I can't understand why it works perfectly on Casini (or whatever the development server is called) on my local machine but crashes on my web server. In both cases they are connecting to the same database.
I would be so grateful if anyone could tell me what I'm doing wrong here. Following are the full error displayed by my server when the site crashes and also what I feel are the relevant sections of my web.config file.Full content of error message and relevant sections of web.config are below:
Server Error in '/' Application.
Value cannot be null.
Parameter name: type
[code]....
I am querying a datagridview and it works great unless one of the cells has nothing (dbnull). How to over come this?Exceptions: Operator '=' is not defined for type 'DBNull' and type 'DBNull'.
Dim query = From row As DataGridViewRow In DataGridView1.Rows _
Where row.Cells(SelectedColumnIndex).Value = filter _
And row.Visible = False _
Select row Distinct
How to check whether a column is null i use the following code but I got this error "Input string was not in a correct format."
[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
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 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 am getting this error, Not sure why it is happening "Error The SqlParameterCollection only accepts non-null SqlParameter type objects, not Int32 objects."I have tried with all sorts of possibilties, now try to enter default data as dummy data,
Using connection As New SqlConnection
connection.ConnectionString = ConfigurationManager.ConnectionStrings("DentalDeviceConnectionString").ConnectionString
connection.Open()[code].....
I'm using an interop dll in a VB.NET project to get access to some functions in a MFC project.
Dim bIsSupposedToWork As Boolean = True
Dim api As API = GetObject(, "MyProject.API")
[CODE]...
Why?
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].......
Im trying to make a web service in VB.net is their a way that i can return the results that i get from LINQ. ie "return objreturnLINQResults" I have tryed to set my Public Function GetAlarmsByGUIS(ByVal DeptGUID As String, ByVal IdNumber As String) As Linq.DataContext . i just keep getting errors.
Public Function GetAlarmsByGUIS(ByVal DeptGUID As String, ByVal IdNumber As String) As Linq.DataContext
Dim lqAlarms As New linqAlarmDumpDataContext
[Code].....
I have a XML file on which when I run a Linq query returns nothing in the for loop.
View 2 Replies