How can I change the following code to write to the database null instead of empty strings?
Public Sub SetChangeRequest(ByVal referenceLeaseID As Integer, _
ByVal referenceCustomerID As Integer, _
Optional ByVal custUnitNum As Object = Nothing, _
[CODE]...
I have a DataGridView that has some columns with dates. It binds to an in-memory Datatable which gets loaded from an string array of data passed back from the backend Some of the rows returned have nulls for the date columns. Solution 1: If I define the Date column in the DataTable as "string" I can easily convert those nulls to empty strings and display it in the grid as empty strings (desired results). However, if the user clicks on the date column header to sort by date, it doesn't order the rows as you want. You get a purely string sort order. Not acceptable
[Code]...
I have a form and stored procedure that inserts the data from the form. It works fine except that if a field isn't filled in it doesn't insert a NULL into SQL it inserts "".
I've tried a few different ways but none seem to insert NULL, the one below still inserts "", can anyone point me in the right direction?
Here is the required part of the code, if you require more just let me know.
Dim rdr As SqlDataReader
Dim cmdInsert As SqlCommand = New SqlCommand()
cmdInsert.CommandText = "spPersonalDetailsInsert"
[Code].....
So if I enter nothing into address1 field it should write NULL to screen but it always writes NOT NULL. What does an empty form field equal? in classic ASP it was always "".
am trying to write to a database via a stored procedure. I am trying to save my values to an object and then write to the database. When I click the button to save the record I am getting a null reference.The below is from the frmDMR class.
Public Class frmDMR
Private m_dmrissue As DMRData
Public Property NewDmrIssue() As DMRData
[code]....
I have a little problem regarding the use of DBNull, NULL etc. in VB.net in combination with SQL Server 2k.
More specifically, I want to do something along the lines of this:If x = 0 Then
x = DBNull.Value where x is declared by Dim x as Object. I would rather use Double, but I can't assign DBNull.Value to this, and using Object works quite well, too. But every time I hit this condition, I get an exception: A first chance exception of type 'System.InvalidCastException' occurred in Microsoft.VisualBasic.dll This is not a major show-stopper, since the database value I write x to in the next step, is NULL by default - most of the time! So I need the ability to write NULL to it. If that was not the case, I would have been able to work around this by catching exceptions, I think - but sadly, this isn't really of use then.
This must've have been asked before but I couldn't locate it. In a mixed code project (VB and C#) we were debugging some old Visual Basic code where a statement as follows could be found:
If Request.Params("xxx") <> "" Then
'do something
I considered this a bug as Request.Params could be null, in which case the statement would've become false which wasn't the idea. So I thought. I just found out, -- probably for the tenth time and I will keep forgetting -- that the following two statements are not equal, while Nothing in VB should be equal to null in C# (thought I):
if(String.Empty == null) // always false
If String.Empty = Nothing Then ' always true
Should I dismiss this as a typical Microsoft backward compatibility effort, or should I consider this a huge error in the VB.NET compiler? Does anybody know the Microsoftean opinion on this oddity?
i have a date control on form (vb.net) and by default its value is current date. i want to make its value to null or empty so that no date is shown and user choose from the drop down date calendar.
View 9 RepliesI am getting the attached error when any cell in a row is empty. How to avoid this error and to accept the null values?
View 4 Replies I am getting product id value some times null and empty from databasehere how i check if valule null and empty
productid = IIf(IsDBNull(TempDT.Rows(0).Item("productid")) =
True,
"", TempDT.Rows(0).Item("productid"))
[code].....
I'm deserializing some XML from an old application into an object in my current application. The old XML often has empty elements (<SomeElement />) which are currently deserialized as empty strings (""). I agree that this is the most appropriate behaviour, but it is a minor irritant; I'd rather they were deserialized as Nothing or ideally ignored - the effect would be the same. Is there a means of ignoring these elements? Or can I have them deserialized as Nothing?
View 2 RepliesTo create a string of space characters to a given length using the MS VB namespace I used,
Strings.Space(Length)But without the VB namesapce, how do I do the same thing, is it like this?...
String.Empty.PadLeft(Length, " "c)
The code below works fine as long as there are values within an XML node (For example the <CPU>Intel</CPU> node below) but it throws an Exception error when the node value is blank/null whatever as in the example node <Monitor> </Monitor>.t's ok if the node value is blank, I just want to check for it and not throw an exception error.This question uses the following XML snippet below: Note: The tag <Monitor></Monitor> has no value in it.
<PCSettings>
<SystemSettings>
<CPU>Intel</CPU>
[code].....
I have some application settings that I want to put some error checking in and the below code does not work.
If My.Settings.SmtpServer = ("") Then
MsgBox("SMTP cannot be blank!", vbExclamation, "SMTP App")
End If
I am finding this weird issue. When I do this > activities.Where(Function(a) (Not a.IsDeleted And a.ParentId = 100) It returns an in-memory query & when I try opening it up, it throws a object not set exception. This only happens when there were no items which satisfied the condition. Shouldn't it be returning an empty set? When there are items satisfying the condition, then it returns a list & works all good.
View 1 RepliesI key-in data from textbox to datagridvie..........the date data the format datatable is:
[Code]...
I constantly find myself having to do code similar to the following.[code]Is there anyway to check for both on a single line? When i'm checking a condition for a great number of answers, I sometimes end up with conditionals 6-sets deep. If i check for null first, an error still pops up, even though VB shouldn't check since the first condition failed. i.e.[code]
View 8 RepliesI have the following code that checks if the value in a cell contains a nummeric value.
Private Sub dgvOrderRegel_CellValidating(ByVal sender As Object, ByVal e As System.Windows.Forms.DataGridViewCellValidatingEventArgs) Handles dgvOrderRegel.CellValidating
Select Case e.ColumnIndex
Case 4 'Aantal
If Not IsNumeric(e.FormattedValue) Then
[Code]...
I'm using FileHelper to generate object's property. Here is an example of one property:
<FieldOptional(), _
FieldTrim(TrimMode.Both)> _
<FieldNullValue(GetType(String), " ")> _
Public StoreNo As String
As you can see the StoreNo will either have a value or " ", one of the business policy is to check if the StoreNo is empty or nothing if the object's StoreNo is empty or null then the record will not create.
I though about creating an HasValue Function in the class to check the StoreNo and other properties in the object but I feel like it is a hack.
Public Function HasValue() As Boolean
Dim _HasValue As Boolean = True
If StringHelper.IsNullOrBlank(Me.StoreNo) Then
[Code]....
I don't think this approach is an ideal solution. what if the StoreNo is remove or change to something else. What's the best approach to check object's property?
I have a couple of textfields in a Windows form. One of these textfields is allowed to be NULL. When I enter a value for every field, it is all inserted, no problem. When I leave the field (txtGewicht) blank, I can't seem to be able to insert NULL in Access Database.
If Double.TryParse(txtGewicht.Text, 0) Then
klant.Gewicht = Double.Parse(txtGewicht.Text)
Else
[Code]....
This is what I get:
"Cannot set column 'Gewicht' to NULL, please use DBNull instead"
So I changed 'Nothing' to DBNull.value, but it then tells me that System.DBNull cannot be converted to type Double.
I have a large one dimensional array that is called ArrayHold which is populated at runtime. I run a loop to scan through the array to find out which elements need to be removed based on a few parameters. This all works great, now I am left with two arrays. The original one and a new one which contains the locations of the elements to be removed.
Original Array: ("A")("B")("C")("D")("E")("F")("G")("H")
Second Array with index/count of elements that needs to be removed: ("0")("3")("5")("7")
End result should be preferably not in a new array but a "ReDim" of the original array:("B")("C")("E")("G")
What would be the simplest way to achieve this? I could run a loop to make all the elements that need to be removed "0" or ""? Would there be an easy way of resizing and array by dropping/removing all the white space or empty elements?
This is related to my last question.Even though Access considers Nulls and zero-length strings (ZLS) separate values, often developers wish to treat them as equivalent for the sake of an If...Then statement or some other stretch of code. One way to accomplish this is to write code like this:
' Not so efficient
If IsNull(varAge) or varAge = "" Then
' do something
[code].....
I need to sort a DataTable or DataGridView by a column that is a string value, but with null/empty values at the BOTTOM when sorting ASCENDING. The DataTable is NOT populated by a SQL statement, so no order by. If I do
[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?
I have a stored procedure (SQL Server Express) that returns a count of records:
SELECT COUNT(AdminUserID) AS CountEm
FROM Licenses
WHERE (AdminUserID = @AdminUserID);
Table "Licenses" has a field "CompanyID" which is a uniqueidentifier.
I need to add a clause to the WHERE to exclude records from the count where "CompanyID" is null/empty.
In VB code I'd do this with "If Not (TheCompanyID.Equals(Guid.Empty)) Then"
How would I do this in a stored procedure?
I need to sort a DataTable or DataGridView by a column that is a string value, but with null/empty values at the BOTTOM when sorting ASCENDING.The DataTable is NOT populated by a SQL statement, so no order by.If I doDataGridView1.Sort(New RowComparer(System.ComponentModel.ListSortDirection.Ascending))then it throws an exception, saying that the DataGridView is DataBound, which is correct, but doesn't help me, and I want to keep it databound.
View 2 RepliesI have a problem in that I have five text boxes pertaining to a customer/client, where there is a txtbox for each: Name; Address; City: State; Zipcode. Of course all the txtboxes are "" at initialization. I also have 2 combo boxes and a 2D array for prices which I have finally been able to understand the array logic. I have also been able to do my necessary calculations for.
My problem. The customer information is first to be validated as all being strings and not empty. The combo boxes I was able to get to tie to my 2 dimentional array and get good output and calculations for a finished product. I am just having problems with the error messages. Also I don't want summary totals unless the data is valid. In other words, the user must enter a complete address and make decisions about the two combo boxes, both of which are needed to use the price array. I will change the comboBoxes to represent dress sizes,"S" "M" "L" and "XL" and the other combobox to describe colorRedSatin or colorBlackBroadcloth with a two dollar difference in price between them. 'That would be similar enough to the problem I need to solve.
Basically I do not want any numbers to appear for price of the dress or addons to the dress unless all validation is complete. I do understand how the radio objects work for discounts and check boxes for accumulating accessories. The program should not give any totals untill the user has input all customer information and made decisions about input from combo boxes and selected calculate from menu. Right now it calculates and puts zeros in when choices are not made from the combo boxes by the user. It will include correct amounts for radio buttons and checkboxes if anything is entered. I need error messages for customer inputs and combo box inputs (if not selected from list of option in drop down for choices) (basically if nothing was put in a text box, the text box is empty. Of course the problem is the user must enter something in all 5 textboxes and not get multiple error messages in rapid succession to fix. We can't always count on our users putting in good data.. When I tried a Do While False with ORs I was getting endless looping. I could not get it to work because it will never execute because the control never passes back to the user.
I don't want to list a series of If/Thens becauser the user will see about 7 messages, where he/she only needs to be fed one at the time. I hope someone can give me some direction. I just need guidance on how to validate the text boxes and combo boxes. The code is analyzed with a "Calculate" on the menustrip. I would like for the calculation not to calculate and put outputs into the summery text boxes unless all textboxes are filled and combo boxes are valid for all the customer information and combo box choices for my two combo boxes describing what is needed for the order to calculate. There are also the radiobuttons and checkboxes, DIMs, Const, Variables, but not having problems with that part I have my indexing problems on the combo boxes worked out also, so I am not concerned about those now except for getting the error messages when I should. I hope that I have described my issues fully. I am using visual studio 8 with Windows 7
I am trying to call an external C++ function using VB.NET (answers in C# are fine, I can convert back) which returns a list of device names. This comes in the form of a pointer to a null-terminated array of null-terminated char arrays (correct me if I've misunderstood what I'm dealing with) with a function signature:
long GetNames(char*** names)
Most of the answers to similar questions I've found have involved something more like:
long GetNames(char** names, int length)
It appears from what I've read that I need to give it an IntPtr but I'm uncertain as to how this should be initialized, and in my case I don't know the length of the array. At the moment, in the VB module, I have:
<DllImport("MyExternal.dll", CallingConvention:=CallingConvention.Cdecl)> _
Function GetNames(ByRef names as IntPtr) As UInteger
End Function
I've tried calling the function by passing an IntPtr initialized as IntPtr.Zero or using Marshall.AllocHGlobal, but I always get an AccessViolationException.
Any ideas on how I should be calling this function and how I get the return value into a managed string array would be greatly appreciated.
EDIT: I've found a sample function call in native C as follows:
char **tmplist;
GetNames(&tmplist)
I have this simple-minded query:
select a.str_number+' '+a.str_name+' '+a.str_suffix+' '+a.str_apt AS addr from mytable
This query works as long as none of the concatenated values are not NULL. If any is null, the address does not show.
I tried this:
select IsNULL(a.str_number+' '+a.str_name+' '+a.str_suffix+' '+a.str_apt AS addr,'') from table
What I would like to accomplish is to replace NULL with empty space if the value is null but I still get no values.
Im trying to create an empty element in an xml file but still want to be able to close other elements without changing the empty element.What XMLTextWrite does to empty elements:
<Data>
<Feed>
<EmptyElement />
</Feed>
<Data>
When i use the text writer i cant use <writer>.StartEndElement() it starts to screw with my empty element. When im still having my program write inside feed. Here some code your you to drool over.
My example
Dim Settings As New XmlWriterSettings()
Settings.Indent = True
[code]....
I am writing a string to a xml document.I now have several different strings and I want to write all of them to one xml file. Is there any way of doing this instead of having numerous single xml files?
View 3 Replies