Can Objects With Null Values Be Serialized
Dec 27, 2011I have used XML serialization to persist objects in my application but I am now interested in using null- able Data types for properties. Will I still be able to serialize?
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Get Away With Packing Data Into Serialized Objects?
Feb 24, 2011I have a thought about using a Serializable Collection containing both data objects and also sub-collections as a low-grade database, meaning it's going to store data objects that are expected to be added to regularly and deleted from occasionally.
View 3 RepliesTcp/ip - Consecutive Serialized Objects Not Deserializing?
Mar 28, 2009This is my first post on here--I've been teaching myself VB via forums like this and MSDN for about 2 years now. I'm programming a computerized economics experiment, and I'm using a communications package that a guy I worked with developed. He and I have been going back and forth trying to figure out what the heck is going on.
The upshot of the communications package is that there's a serializeable MQMessage class that we send back and forth, essentially just a package of an integer (Type), string (Text), and Object (Data). Most of the time, this goes according to plan.
The problem is this: If the client receives two or more messages back-to-back, the client stops raising the MessageArrived event. (and presumably, the same would hold true for the server--I should test this, but jeez-oh-man, I've been running test after test for the last week).It's still connected, as on disconnect it throws the "Socket forcibly closed" exception. When it receives multiple messages sequentially, it's still receiving the data, it just never knows when the first message ends, and the buffer just keeps filling and filling. The problem seems to be that it can never successfully Deserialize the MQMessage object, and so it returns Nothing on the getCompletedMessage function and just keeps adding to the buffer (ABuffer.Length goes 1024, 2048, etc.).
Changing Datatypes Of Properties Of Serialized Objects?
Jun 18, 2009Changing datatypes of properties of serialized objects?
View 1 RepliesSend And Receive Serialized Objects Over A TCP Connection
Jun 7, 2010How can I send and recieve serialized objects over a TCP connection with size and data type values in the header (within array(0) and array(1) values)?I know how to serialize and send the object using BinaryFormatter.Serialize.I dont know how to take the recieved data and put it into an array of bytes().Also - on the receiving end I dont know the size of the object sent therefore I dont know when to stop reading the data stream so I cant use: Dim Obj As ClassName = DirectCast(BinaryFormatter.Deserialize(Stream), ClassName).
View 1 RepliesSql - Error The SqlParameterCollection Only Accepts Non-null SqlParameter Type Objects, Not Int32 Objects?
Jun 23, 2012I 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].....
The SqlParameterCollection Only Accepts Non-null SqlParameter Type Objects Not String Objects?
Jan 18, 2012Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Using conn As New SqlConnection("Database=Clinic_Management_System;Data Source=.SQLExpress;Integrated Security=True;AttachDBFilename=|DataDirectory|Clinic Management System.mdf")
Dim cmdRecord As SqlCommand
[code]....
Modifying Objects Inside For Each Loop Sets Properties Of All Objects With Values Of Last One?
Jan 29, 2011I have a program like this.
Module Module1
Public Class Mstr
Public Property Prop1 As String
Public Property Prop2 As String[code]....
But it is not working as I expect it to. You can see it from.The DtlsB properties of all three DtlsA objects are having values from last iteration.
SqlParameterCollection Only Accepts Non-null SqlParameter Type Objects
May 16, 2011I am developing a VB.NET application with SQL Server 2008 and I get the above error when I try to run this ASPX file. What is the cause?
[Code]...
Dynamically Creating Objects - Error: A Null Reference Exception
Apr 13, 2011I am working on creating an application (game) for a PocketPC with Visual Studio2005 in VB/.NET. I try to dynamically create a (new)button upon clicking a label and assigning certain properties to this button. For this I used below displayed code, but this button does not appear on 'Form1' - which is big enough to display it- but creates an error: A NullReferenceException. Such occurs when you try to reference an object in your code that does not exist, but I think I just did by using'..New..' Who can tell me what is wrong and how to fix this? [Code]
View 16 Replies.net - Handle Null Nested Objects In RDLC Report That Is Bound To Custom Assembly Object Datasource?
Aug 27, 2009I have an RDLC report that I am rendering directly to the Response Stream as PDF (rather than using the ReportViewer). In the code that renders the report, it's DataSource is bound to a List(Of ClassA) objects defined in a custom assembly. This seems to work for the most part. My problem is that I can't seem to handle the situation where a nested object is null. For example, given ClassA and ClassB (the nested object) defined as follows:
Public Class ClassA
Public Id As Integer
Public Name As String
[Code]....
the report displays "#Error" if TheNestedObject is null. If TheNestedObject is not null, it correctly displays the Name.
Allow Null Values In Listview?
Feb 16, 2012I'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 RepliesAllow Null Values To Appear On The Textbox?
Jun 3, 2011what 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
Column Does Not Allow Null Values
Jul 30, 2009I 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.
DB Null String Need Values
Jun 9, 2012I 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]...
DirectCast & Null Values?
Jun 4, 2012I 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...
Excel Values Become Null ?
Oct 15, 2009I'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).
Handling Null Values In A DB
Jun 25, 2011I 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]....
Null Values In Text Box?
Mar 18, 2010So 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]...
Saving The Null Values?
Oct 8, 2009Have 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 RepliesSqlDataAdapter And Null Values?
May 29, 2012I 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].....
VS 2010 Null Values
Nov 10, 2011I'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 RepliesWriteXML With Null Values?
Jun 3, 2005I 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 RepliesAsp.net - SQLDataReader: Dealing With Null Values?
Feb 9, 2010Some 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)
Combobox Is Displaying Null Values?
May 19, 2012the 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]....
Dealing NULL Values In SQLDataReader
Jan 12, 2012Dim myreader As SqlDataReader = cmd.ExecuteReader
'read information from the database and give the values to the arguments(column_1, and column_2)
While myreader.Read
column_1 = myreader.GetString(1)
column_2 = myreader.GetString(2)
.....
I get an error when the data returned from myreader.GetString(2) is NULL. How do I check for nulls before assigning column_2 a value?
Displaying NULL DateTimePicker Values?
Jan 4, 2010I 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.
How To Insert Null Values To Database
Nov 17, 2011I am working asp.net vb application. I have set of values to be inserted to Database.But their some fields are optional to be filled. I need to check the textbox empty. If empty I should not enter the value to Database. How to work on this?
View 4 RepliesSQLDataReader: Dealing With Null Values?
Jul 8, 2010Some 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
[code].....
What Are NULL Values, How To Handle Them In SQLite
Apr 26, 2011What 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)