I tried to execute a code that will display Book Titles in alphabetical order within a list box and received an ArgumentNullException (Value cannot be null. Parameter name: item) error.
Dim strBook As String
Array.Sort(_strBookTitle)
For Each strBook In _strBookTitle
Me.lstDisplay.Items.Add(strBook)
Next
am a beginner for vb.net, i was using the WROX book to start of with vb.net.In that i had an example code which i tried to work out but i got an error like this one ,am jus creating an array and adding it into the list value cannot be null.Parameter name:item
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I am getting an error when I write a value to the database. it tells me "Key cannot be null. Parameter name: key". However the key is an auto-increment value and i'm not even writing to that field. I have verified that there is a value being sent to the SQL. I also created a seperate program that writes the same SQL statement to the db and it writes just fine. I also have other places within the same program that write to the database without any problems.[code]
View 17 Repliesi'm having some problems here.i try to put in some data into sql server by using vb code. the data types are small integer and unsigned tinyint.i would like to assign the value as NULL instead of '0' because my reading takes 0 and 1.i tried in this way.
Dim Ignition As Integer = Nothing
Dim ADCCount1 As Integer = Nothing
Param = New SqlClient.SqlParameter("@Ignition", Ignition)[code].....
when i viewed my sql table i found that the Ignition and FuelRead1 show 0.previously i tried to set the value to NULL but it showed error.What should i assign the ignition and ADCCount1 so i will obtain NULL in database?
Following is the code where i am getting the "Value cannot be null. Parameter name: Key" exception.
I cant see anything wrong in this code.
ReadOnly Property dvMeasurements() As DataView
Get
Dim dvMeasurementsRet As DataView = Nothing
[Code]....
How can I detect null value of sql parameter?In VB6 IsNull(), in VB.NET its return error
View 5 RepliesIn the following fragment I want to set vID2 to NULL (and not to 0) if mID2 is an empty string. How do I do this? There is apparently no OleDbType.Null
cn.Open()
strTemp = "INSERT INTO tbShips (vNew_b, vID, vID2) VALUES(?, ?, ?)"
MyCommand.Connection = cn
MyCommand.CommandText = strTemp
With MyCommand.Parameters
[Code]...
The problem started when I changed a multiline rich TextBox WordWrap to false..I'm not sure whether I attempted this when the program was running or not. The error list recorded the location as 0, 0.I have attempted to trace the problem by removing the <System. Diagnostics. Debugger StepThrough()> _ attribute in the Sub InitializeComponent located in the Designer module. However, nothing indicates there is a problem within that module.Since this situation occurred, I cannot initiate a ToolStripMenuItem_Click event procedure, located within a pop-up menu, by a right-click of the mouse. I have since attempted to reinitiate the error and the only way I can revisit this error is by changing the WordWrap of the RTB whilst the program runs, but no error is respectively listed or initiated within either the error list or designer module. If the program is running - without an attempt to reinitiate the error - I'm unable to run the pop-up menu.
View 1 RepliesI have a VB.net application that has been built for awhile. I recently added a barcode in active reports 6 to one of the reports. everything works fine on my machine as well as others, but a select few get an error relating to the following: [Code] Do I need to update the mscorlib.dll on the users machine? I'm not sure why this error is happening.
View 1 RepliesI've been upgrading my vb6 app to VB.NET and so far everything was going on smoothly until this morning. I'm getting this message : value cannot be null. parameter name context when trying to save or when adding new controls. It's kind of a random error, it does not always happen when saving or adding new controls
View 6 RepliesValue cannot be null. Parameter name: stream
Can anybody assist my code?
Me.PictureBox1.Image.Save(memStream, System.Drawing.Imaging.ImageFormat.Jpeg)
Dim imSource() As Byte = memStream.GetBuffer
Dim imStatus As Integer = publicStream.Read(imSource, 0, streamLength - 1)
imSource.GetValue(memStream.ReadByte)
I get the following exception for the code shown below. The error occurs when i request access token.I downloaded the latest dll(2.3.1) from the twitterizer website.
{"Value cannot be null. Parameter name: String"}
Dim OAuthTokens As New OAuthTokens
Dim accessToken As New Twitterizer.OAuthTokenResponse
accessToken = OAuthUtility.GetAccessToken(ConsumerKey, ConsumerSecretkey, "oauth_token", "oauth_verifier")
Upon loading my project i get this error and says "Instances of this error (1)" and shows the Call Stack as follows
at System.ComponentModel.TypeDescriptor.TypeDescriptionNode.GetRuntimeType(Type objectType)
at System.ComponentModel.TypeDescriptionProvider.GetRuntimeType(Type reflectionType)
[code].....
im getting error when im trying to view a report from my vb2010. value cannot be null. parameter name: dataReader the following is the screenshot for my error and the codes:
[Code]...
How can i check if an output parameter is null before i bind it to a asp literal, and if it is null i want to just make the literal [code]...
View 1 RepliesI think this is a pretty basic question, but I just want to clarify. If I have a variable with a null value, and pass it as a parameter that is optional, will the parameter get the null value, or the default value?
dim str As String = "foo"
dim obj As Object
//call 1
[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 am hardcoding an insert statement to a database, based on certain details a user enters into a windows form. The form has a few textbox and datetimepicker controls for the purpose. This form enters a single row in a single table in the database.The table has a few possible null columns defined, in those cases where the user does not have any data for those columns at that particular time.
I have to provide controls for passing data to those null columns nevertheless. In my case, I have two such columns that accept null values, and two corresponding controls - a textbox and a datetimepicker. The datetimepicker has a checkbox added to it so that if it is supposed to be null it doesn't pass the default current date value, and remains unchecked to explicitly specify that it is supposed to be null. By default it is unchecked.
My code is structured as follows:
Form1:
'the sub referenced here resides in a dll file in my dataaccesslayer code, and in my actual example is referenced properly.
'I have shortened the code here for simplicity
[code]....
Now it gives me an error whenever the code comes to the executenonquery(), and says something to the tune of "SqlDateTimeOverflow. Must be between 1/1/1753 12:00:00 AM and 12/31/9999 11:59:59 PM."
I think the value of 'Nothing' from the subprocedure's paramter is not being assigned to the sqlcommand's parameter as a database NULL, which is what I need to pass to the database.I know instead of using optional parameters I can easily create overloaded subprocedures where one sub allows not passing values where the column(s) is supposed to null and other overloaded subs permit combinations of which column(s) are null or not. But it is simple as long as there is just one, or at the most two null columns in a table. If I have dozens of null values in a table that the user can choose to enter or not in a data entry form?
I have already defined in my SELECT statement in TableAdapter to tell it what to do if the parameters are Null:
SELECT a.ID, a.NameID, b.BNameID
FROM a INNER JOIN b
ON a.ID = b.ID
WHERE ((@NameID IS NULL) OR (a.NameID = @NameID))
AND ((@BNameID IS NULL) OR (b.BNameID = @BNameID))
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'm getting the following exception when I try to run up my Winforms app and haven't been able to find a solution to it:
System.ArgumentNullException was unhandled
Message=Value cannot be null.
Parameter name: activationContext
[code]....
I've added a handler for the "unhandled error" event in the applicationevents class but it never reaches that stage and there is no source code running that I can break into and diagnose.
The application was fine until I added a user control (nothing fancy, just a standard windows user control) and then dragged it onto a form in the app (user control and form were in the same application). The application builds and compiles without any errors or warnings but when I attempt to run it up I get the above error straight away.
Does anyone have any idea what it could be or even how I can go about investigating it? I'm a bit stumped on this one as I'm not sure how to investigate it. I removed the user control from the form and then I removed the user control from the application entirely but the error hasn't gone away. In all honesty the addition of the user control might be a red herring but the problem manifested straight after adding it.
I have a stored procedure which updates a database using the parameters I supply but I'm having trouble passing a NULL to the stored procedure
The field I need to make NULL is a DateTime field
DB.Parameters.AddWithValue("@date", NULL)
This gives me the error 'NULL' is not declared. 'Null' constant is no longer supported; use 'System.DBNull' instead
[Code]...
I'm building a custom calendar control that queries our database to display corporate events. Here is the situation, there is an EndDate value stored and on the dev system one of the events have a NULL value. No big deal since it's only a test system, but might as well check before trying to use it anyway on the safe side. I figured the following code would work:
While dr.Read()
corporateTable.Rows.Add(New Object() { _
Convert.ToDateTime(dr("EventBeginDate")) _
[code]....
The thing that really gets me is, at one point I had this:
, IIf(dr.IsDBNull(column), Convert.ToDateTime(dr("EventBeginDate")).AddDays(1), Convert.ToDateTime(dr("EventEndDate"))) _
Thinking that it should work because it should only evaluate the dr() if it's not NULL. However, it kept erroring out at the end because the value was in fact NULL.Why is it that even though I'm checking if it's NULL before using the value, it errors out at the part that doesn't get called unless it's not NULL? Does it have to do with the fact that I'm using the IIF() and it's evaluating the whole statement? Or, using the dr(), it evaluates at runtime?
DataGridViewX.CurrentRow.Cells.Item(0).Value.ToString
If the item is blank and no data is entered it will throw a null exception, so the question is that how can I check if the item is null or not? Even using this:
If DataGridViewX.CurrentRow.Cells.Item(0).Value.ToString IsNot Nothing Then ...
Will throw the exception!
Well i want to add a listview item to the paramater of a Webclient DownloadString here is what i want
vb
Private Sub Form1_Load(sender As System.Object, e As System.EventArgs) Handles MyBase.Load Dim wClient As New WebClient AddHandler wClient.DownloadProgressChanged, AddressOf DownloadProgressChanged(ListView1.Items(textbox1.text)'HAVE THIS IN HERE' AddHandler wClient.DownloadStringCompleted, AddressOf DownloadStringCompleted(ListView1.Items(textbox1.text)'Have THIS IN
[code]....
I m struggling in setting the Value in List Picker to be the one I want.
I have that in xaml
<
DataTemplate
x:Key="ListPickerED">
[Code]....
I have a property called ReplacementTo and I set a value to it based on the selecteditem from the combobox, like this:
classEquipmentItem.ReplacementTo = cmbReplcmnt.SelectedItem.ToString
Now I can't use cmbReplcmnt.Text because what I actually need is the value of that SelectedItem
So problem is, if the user leaves the combobox as blank, it throws a null exception.I decided to use the IIf function then:classEquipmentItem.ReplacementTo = IIf(IsNothing(cmbReplcmnt.SelectedItem.ToString), classEquipmentItem.ReplacementTo = "", cmbReplcmnt.SelectedItem.ToString)
Unfortunately I still get the error I tried using a Try-Catch for it and it worked, but I don't want to rely on the Try-Catch, so I was wondering is there a another way to work this through?
Currently, the following code shows a blank line if Address2 (which comes from the database) is Null. How can I condition on the value of <%#Container.DataItem("Address2")%> so I can get rid of the blank line if Address2 does not exist (or is Null) in the database? If code in the code-behind is needed
<asp:repeater id="rptLabels" runat="server">
<HeaderTemplate></HeaderTemplate>
<ItemTemplate>
[Code]....
i have an image in an bytearray. I convert thiy bytearray to an image an do a resize on it which works fine. But after that i want to convert it back to a bytearray and then i get a "Value Cannot be null Parameter name: encoder" Exception when trying to do a IMG.SAVE(MEMORYSTREAM, IMAGE.RAWFORMAT)
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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?