I 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.
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I'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 Replieswhat 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
I 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.
I 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]...
I 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...
I'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).
I 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]....
So 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]...
Have 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 RepliesI 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].....
I'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 RepliesSome 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)
I 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?
View 6 Repliesthe 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]....
Dim 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?
I 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.
I 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 RepliesSome 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? 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)
i am not getting the integer values in dataset while reading from an excel files the field which is integer will be showing as NULL.
View 1 RepliesI created a connection string for an excel file. I prefer this method as opposed to creating "Excel" objects since it is not restricted to a specific version of Excel.When I connect to the excel file, I step past the first few rows since they have data that is not needed. When I reach the first field that contains a date, then I begin my data import. However, at that point (A8), it shows the cell in the "A" column as having a Null value even though there is indeed a value in the cell. Columns "B" and "C" are fine.
View 1 RepliesOn a ASP.net form, I need to add a textbox to update a date field in MS SQL server via stored procedure. I want to verify user input cant figure out the correct syntax to do so (please see below)
If d.Text <> "" Then
cmd.Parameters.Add("@date", SqlDbType.DateTime)
cmd.Parameters("@date").Value = Date.Parse(d.Text)
[Code].....
I need to round and print a price like below, but this does not handle null values.How can I handle null values on one line of code? DBRSet is an SQLDataReader and the price is money
<%= Math.Round(DBRSet("price"))%>
I have about 200 .aspx pages of this so I could also use some tips on how to change these in an easy way? Can I do a search and replace with a reg-exp or something like that?
For example in my datalist if Eval("OptionJ").Tostring = Null I would like the function GetVisible to set visibility of the radio button to false like so:
<input name="Q<%#Eval("ID")%>" type="radio" value="J" visible="<%# GetVisible(Eval("OptionJ").ToString()) %>">
<%#Server.HtmlEncode(Eval("OptionJ").ToString())%>
[Code]....
In a WinForms app (VS2008 / .Net Framework 3.5) I bind data from SQL Server to controls. If there's a null value e.g. an employee has no middle name (allowed by business rules), when I browse that record at runtime an exception is thrown. So I code: If Not (row("middle_name") Is DbNull.Value then txtMiddleName.DataBindings.Add(New Binding("Text", row, "middle_name)). Say someone adds a middle name to this record, because the control had no databindings the dataset.HasChanges property is false and update stored proc doesn't run. I guess I could handle this like this: If txtMiddleName.Databindings.Count = 0 AndAlso txtMiddleName.Text <> "" Then row("middle_name") = txtMiddleName.Text. I guess I would have to do something similar to handle a value changing from not null to null.
View 8 RepliesI have a FormView where I pull data from one table (MS Access), and then insert it (plus more data) into another table. I'm having issues with the dates.The first table has two date fields: date_submitted and date_updated. In some records, date_updated is blank. This causes me to get a data mismatch error when attempting to insert into the second table.It might be because I'm databinding the date_updated field from the first table into a HiddenField on the FormView. It then takes the value from the HiddenField and attempts to insert it into the second table:
Dim hfDateRequestUpdated As HiddenField = FormView1.FindControl("hfDateRequestUpdated")
myDateRequestUpdated = hfDateRequestUpdated.Value
'... It then attempts to insert myDateRequestUpdated into the database.
[code].....
I have a table with the below structure.
ID VALUE
1 3.2
2 NULL
4 NULL
5 NULL
7 NULL
10 1.8
11 NULL
12 3.2
15 4.7
17 NULL
22 NULL
24 NULL
25 NULL
27 NULL
28 7
I would like to get the max count of consecutive null values in the table.
From r In ReceiptLines
Where
r.RECEIPT.RECEIPTDATE >= _reportStartDate
And r.RECEIPT.RECEIPTDATE <= _reportEndDate
[Code].....
I am fetching all departments and their sales, average, count from the ReceiptLine, Receipt, ReceiptDiscount tables. The problem i am facing is, if i remove where discount > 0, I am getting null exception. But if I include that, then I only get sales that has discount. How would I write query that bring all sales less discount (if it has one).
If I have a datatble column set as int16 but rows can contain null values for this column. How do i write the linq query. I keep getting an error null value exception. Dim query = From n In resultstable.AsEnumerable Where n.value is dbnull.value does n't work.
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