I have a Job Register Table and that table doesn't have any records.
This is my LINQ code:
Dim QRecordCount = (From LC In CntxtJobDetails.JobRegistrations _
Where LC.JobCode <> 0 _
[code].....
When i execute this linq to sql command its given an error "The null value cannot be assigned to a member with type System.Int32 which is a non-nullable value type." 0 Records in my Commotidy Table
I want generate manual number and get the last CommodityCode.My Code as follow,
Dim QRecordCount = From RC In cntxtCommodity.CommodityMasters _
Where RC.CommodityCode <> 0 _
Select RC.CommodityCode[code].....
Lets say I have two tables:
Parent
PK
ParentID[code]....
These tables have a relationship where the Parent can have 0 to many Children.I wrote this query "Select * from Parent left outer join Children on Parent.ParentID = Children.ParentID", thus returning all Parents regardless of whether they have children.This would return something like this if run directly against the database:
ParentID
FirstName
LastName[code]....
Now what I would like to do is use the ExecuteQuery method on my LINQ data context to run this query and return the set of objects related to it.What I am expecting to happen is have LINQ return two Parent objects one (Joe Smith) with one child in its Children collection and one (Tina Jones) with nothing in the Children collection.However what I am getting is an exception stating "The null value cannot be assigned to a member with type System.Int32 which is a non-nullable value type.I am assuming, since the error message is not very descriptive, that it is talking about the fact the ChildID is an integer and is not nullable and cannot correctly generate a Children object with that value.
Im trying to set one variable equal to another but it says "No default member found for type 'Decimal'" what does that mean?Both the varuables are deciamls, one is a regular decimal that I declare in the sub and another is an array that I declare in the class. The line is:
tempx = xo(i)
this is in a for loop with i as the variable.
When using the If operator [URL] to assign a value to a System.Nullable object, if the result is Nothing (null), then 0 is assigned to the object. Example: 'Expected value is null (Nothing). Actual value assigned is 0. Dim x As System.Nullable(Of Integer) = If(1 = 0, 1, Nothing) If x is a nullable type, why is it being assigned the default integer type of 0. Shouldn't it receive a value of null?
View 2 RepliesI have a generic Class I'm using to hold information loaded from a database.I have a method which takes a DataRow as an argument, uses the object's known column name and extracts the data from the DataRow, such that:Dim loadData As T = CType(myDataRow("myColumnName"), T))works as my default assignment in most cases.Unfortunately, due to some horrifying design constraints, some of my columns may be null, and may also be taken from enumerations.This means that when <T> is Nullable(Of SomeEnumeration) the above code does not work because I can't cast 0 directly to SomeEnumeration.Zero.Is there some way to check whether <T> is Nullable(Of [Enum])? Or some way to write a method which allows Integers to be cast to Nullable(Of [Enum])?I feel like I'm forgetting something that would allow me to write one of the other of these, but my weak google-fu is turning up nothing.
EDIT: Okay, thanks to dasblinkenlight's answer below, I can detect when this circumstance is occurring, but what I need to do now is to take a type <T> which I know is Nullable(Of SomeClass), get a type reference to SomeClass and then create a new object of type Nullable(Of SomeClass) and assign that to LoadData.My problem was that I had a lot of difficulty in finding any function which would accept baseType as an actual Type.Parse accepted baseType as a parameter, I knew baseType was an [Enum] type because of dasblinkenlight's code, so I was, in this instance, able to code a solution. It's a solution which is very specific to my problem (i.e., T is Nullable(of SomeEnumeration)), but it's a solution nonetheless.
how do I overcome it? I have created a class and compiled into .dll This code
[Code]...
In Visual Studio 2008, if I do this:
[Code]....
Does anyone here know how to get the above to work WITHOUT warnings being generated?
In the following code i get a warning at line 59:Warning 1: Access of shared member, constant member, enum member or nested type through an instance; qualifying expression will not be evaluated.and.. At line 78 I get this Warning:
Warning 2 Property 'SelectedCustomer' doesn't return a value on all code paths. A null reference exception could occur at run time when the result is used.
The program compiles and runs well, but i cant' undesrtand the reason for these warnings. Any Idea ?
1: Public Class Form1
2:
3: 'Form level members
4: Private objCustomers As New ArrayList
[code]....
I am pulling data from a local MSSQL database using a stored procedure, then send the data to a web service. Every part of the component works well except for a pesky problem will a DBNull being returned from the DataRow field, when I know that the field is not null and has valid data. The database and associated INSERT statements that add to this field are designed to not allow NULL entries. When I debug break the program on or right before the line that throws the error I see that the field has valid data for the current row.If I add a null check to the code (as below) the operation continues as normal:
Dim dataResultsTable = Me.myViewTableAdapter.GetData(int)
For Each myDataRow In dataResultsTable.Rows
If worker.CancellationPending Then
[code]....
Why is the read operation returning DBNull instead of the data in the database?
EDIT: Just to be clear, the operation does return the proper data, but the data is not being saved into the variable.
I'm getting an error after sending a list to a web service.This is the code that is calling the web service:
Dim sProgramInterest As New List(Of Integer)
crmService.InsertProspectGetId(sProgramInterest.ToList)
But I'm getting this error.
[code].....
My project worked a first and now its giving me a problem.The error
Quote:
Unable to cast object of type 'System.Windows.Forms.MouseEventArgs' to type 'System.ComponentModel.RunWorkerCompletedEventArgs'.
[URL]The issue is as soon as I change the value of the text boxes it gives me an error and forces me to close the project.
The error is:Unable to cast object of type 'System.EventArgs' to type 'System.Windows.Forms.KeyPressEventArgs'.
However I'm supposed to clear the number of gallons used and the total charged when a change is made to the contents of the 2 text boxes on the form.
I have an InvalidCastException Error in my program. The program is that i try to insert an employee record into a database table after getting the details from a form. I've used Money data type is SQL Server for salary and SqlTypes.SqlDecimal data type in employee template class. i've used a stored procedure to pass the values and i add the basic value by passing a parameter by the method
Dim prm8 As SqlParameter = com.Parameters.Add("@basic", SqlDbType.Money)
prm8.Direction = ParameterDirection.Input
prm8.Value = emp.Bsc
I've used the money datatype itself even in the stored procedure variable.I get the following error.
failed to convert parameter value from sql decimal to decimal
Even if i use
prm8.Value = Convert.ToDecimal(emp.Bsc)
I get an error Unable to cast object of type 'System.Data.SqlTypes.SqlDecimal' to type 'System.IConvertible'.
Now I want to display picture in picturebox1.To do this I use this codes, but it does not display picture
on this line: Dim arrPicture() As Byte = CType(dt2.Rows(0)("img_path"), Byte())
it shows this message,
Unable to cast object of type 'System.DBNull' to type 'System.Byte[]'.[code]......
I am getting this error when I am tring to load string type to data table)
Using connection As New SqlConnection("connectionstring;")
connection.Open()
Using Command As New SqlCommand("SELECT ClientId,forename,surname from t_clientdetails
[code].....
I get the below error Unable to cast object of type 'System.String' to type 'System.Data.DataTable'.This is the code I'm using
Dim str As String = String.Empty
If (Session("Brief") IsNot Nothing) Then
Dim dt As DataTable = Session("Brief")
If (dt.Rows.Count > 0) Then
[code]....
Unable to cast object of type 'System.String' to type 'System.Windows.Forms.TextBox'.
View 12 RepliesVB 2008, DataGridView,DataGridView1_CellLeave(sender, New System.EventArgs)
"Unable to cast object of type 'System.EventArgs' to type 'System.Windows.Forms.DataGridViewCellEventArgs'."
What is the Correct String for "New System.EventsArgs"
Anybody there is to help me out.
I'm creating a student evaluation form in a repeater that should submit the evaluation responses and update the SQL database, but I keep getting the error mentioned in the title. I'm coding in ASP.Net using VB.
Here's my code:
Student.aspx
<asp:Content ID="Content1" ContentPlaceHolderID="HeadContent" runat="Server">
</asp:Content>
<asp:Content ID="Content2" ContentPlaceHolderID="MainContent" runat="Server">
[Code].....
I am getting a really bizarre error and it makes no sense at all.Basically I have a user entity which has a Password property. This property is of Type Binary, the server data type being Binary(512).I am reading this value in and converting it to a byte array. However whenever I run my code I am getting a completely unrelated error of Unable to cast object of type 'System.Guid' to type 'System.String'.This strikes me as very odd since I am not using a property or variable of type string or GUID anywhere in this procedure where it falls over.
The code is below:
Public Shared Function ValidateUser(ByVal username As String, ByVal password As String) As UserValidationMessage
Using db As New EntityMapDataContext
Dim u = From user In db.Users
Where user.Username = username
[code]....
Code: Dim dom As New DOMDocument30 dom.async = False
dom.Load(serverAddress & "/App/filelist.jsp?type=content")
For i = 0 To dom.childNodes.item(1).childNodes.length - 1 downloadfile(dom.childNodes.item(i), mcount, currentpath) Next
The above code is activated upon clicking of a button. i have the server address declared. and using the domdoc to load the jsp file to generate the xml data. and using for loop, i call the download file function which accepts the following parameters
Code:Public Sub downloadfile(ByVal domdoc As Xml.XmlNode, ByVal totalcount As Integer, ByVal currentpath As String)
The totalcount and currentpath work fine, but when i pass in the dom.childNodes.item(i) , error pops up.
--------------------error message------------------------------------------Unable to cast COM object of type 'System.__ComObject' to class type 'System.Xml.XmlNode'. Instances of types that represent COM components cannot be cast to types that do not represent COM components; however they can be cast to interfaces as long as the underlying COM component supports QueryInterface calls for the IID of the interface.-------------------------------------------------------------------------------
[code]....
When testing the followng code from Mastering VB2010, I get an Unable to cast object of type 'System.String' to type 'System.IFormatProvider' exception.In the Button1_Click event code Dim strmOut As New System.IO.StringWriter(SaveFileDialog1.FileName)the 'SaveFileDialog1. FileName' is underlined with a green squiggle and displays the following tool tip:Runtime errors might occur when converting 'String' to'System. Iformat Provider'.This is apparrently the problem but what does it mean and how do I fix it to get the code to work? 'Code being tested that runs the exception:Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click.[code]
View 12 RepliesI have a page that get value from SQL. I'm having a problem when I initialize Label object with field having TEXT data type.[code]...
View 4 RepliesI have a bit of trouble right here, I am trying to get the data from the site and input them in the listview. Well, when my main app start to load through on debug, then it start to display a warning. The warning is: Unable to cast object of type 'System.String' to type 'System.IFormatProvider'.
[Code]...
When trying to compile my newly created ClassLibrary class 'Validator' that validates entries made into TextBoxs or MaskedTextBoxs, I get the following error:
Warning 1 Namespace or type specified in the Imports 'System.Windows.Forms' doesn't contain any public member or cannot be found. Make sure the namespace or the type is defined and contains at least one public member. Make sure the imported element name doesn't use any aliases. C:Users erryDocumentsVisual Studio 2008ProjectsMillerClassLibMillerClassLibValidator.vb 1 9 MillerClassLib.
Following is the first part of code in the class:
Imports
System.Windows.Forms
Public
Class Validator
[code]....
What can I do to resolve this problem? The classes in this class library will be used to validate forms data input in a number of varied projects.
I'm getting a sporadic 'Unable to cast object of type 'System.Int32' to type 'System.String' Exceptions at .SingleorDefault() in the below code. It works 9/10 times but randomly it throws an exception. I made sure that SettingID that i'm passing has no Null Values and the data in the table always exists for the settingID, and i'm always passing SettingID as Integer.
[Code]...
I am using VB2008 in VS Prof and try to convert at Byte arry stored as a Image format in Sql2000 database.
Code:
Using acnLoc As New SqlConnection(CSLoc)
acnLoc.Open()
Dim G As SqlCommand = New SqlCommand("SELECT [SignatureData] FROM [MyTable] where [OID]=@OID", acnLoc)
G.Parameters.Add("@OID", SqlDbType.Int).Value =Cint(bxShipmentno.Text.Trim())
dim P= G.ExecuteScalar() 'returns a system arry
[Code]...
[Code]...
Unable to cast object of type 'System.Net.FileWebRequest' to type 'System.Net.FtpWebRequest'.
i get the error in following code
Function ReadFile(ByVal sPath As String) As Byte
Dim data As Byte
data = Nothing
[Code].....