i have a combobox which get value from database through dataset. when i run the program n click on the combobox, the value is auto fill in with data from database. is there anyway to add a blank entries to the selection on the combobox??
View 5 RepliesThe combobox is bound via binding source to a table. How can I display the list of look up options while having the first option say [None} and if selected, clears the value from the list.
View 2 Repliesthe input box cannot grab the NULL value (blank).
i'm try make try and catch. let's see my code..
Private Sub GetData()
Dim row As Integer = DataGridView1.Rows.Count
Dim N As Integer
[Code].....
Error:Value of type 'System.DBNull' cannot be converted to 'Integer'. can you show me a "hack" to use null / blank ? to read it and catch the err0r ?
'Attributes
For Each attRefID As ObjectId In myBRef.AttributeCollection
Dim myAttRef As AttributeReference = attRefID.GetObject(OpenMode.ForRead)
[Code].....
How do I tell if my Enumerator property hasn't been given a value?
How do I tell if it is blank?
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 am trying to pull sql data into a text file. The code works just fine, until some new data comes in from lazy employees and a couple fields (used for notes/comments) are now left blank. Originally I've never seen them blank so I didn't think anything of it.
col2 = myreader.GetString(1)
It will error if the field is ever null - I even tried using a case when:
case when note is null then '" & empty & "' else note end and set the variable emtpy = '', but vb still thinks that it's null and errors?
How can I get this to happen? I googled around and it seems setting the CUSTOM FORMAT to " " when the field is null will work but not for a BOUND datetimepicker.
View 12 RepliesIn my window application, Form1 variable eg. Public str as string. value blank/null when move to Form2 and Back to Form1. How to maintain Form1 varable's value when back to Form1 In vb.net if any one know, reply me soon
View 2 RepliesI am working on a timekeeping application, using Visual Basic 2008 Express edition with an Access 2000 database.The application requires the user to complete a timesheet by recording in tme and out time daily. Blank fields are perfectly frquent and perfectly legitimate.Using these lines of code it works perfectlywhen there is a time value in the database.[code]This indicates to me that the code to ignore a field containing nothing is not working
View 10 RepliesI am not sure about method to publish my program. But basically when I publish it no errors at all...I have database name usurfdb.mdb. I have set it build action to content and copy to outputdirectory = copy if newer.Should I amend anything on my usurfdbdataset1.xsd as well like I did on my .mdb?
Dim con As New OleDb.OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;Data Source=|DataDirectory|u-surfdb.mdb;")
I am wondering, When I try to locate the location of my database after the program
I have 2 inputs from 0-180 for x and y i need to add them together and stay in the range of 180 and 0 i am having some trouble since 90 is the mid point i cant seem to keep my data in that range im doing this in vb.net
Ive created one database Sql Server Compact Edition 2005, with one table ("Cliente") I know that I can created my database good, but i have a problem saving information since three textbox, in my table(With columns "Nombre" "Apellido" "Cliente". In my form there is a button save ("Guardar"). When I do click in my button appear the next message : "The column cannot contain null values. [ Column name = Nombre,Table name = Cliente ] " and happen the same with apellido and Id_Cliente. And this happen becouse my code cant save the information....
This is the code
Option Explicit On
Option Strict On
Imports System
Imports System.IO
Imports System.Data
[CODE]...
And the code for my button is:
Private Sub cmdguardar_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmdguardar.Click
Dim myconnection As SqlCeConnection
Dim mycommand As SqlCeCommand
[CODE]...
I want to add a blank value to a field in access database with vb 2008 command.
Problem 1: Here is my code, it shows conversion to string not possible errors
Private Sub btnRedThrow_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnRedThrow.Click
Dim dbCnct As New DBUtills
[Code]....
notice the fifth and last value is empty. But it is not being added into the database, how do I do that?
Problem 2: Why does an additional field from my access database disappear even after I manually created the field?? (access database 2003 version, extension is .mdb) I'm using visual studio 2008
I have problem insert records from my vb application to my access .mdb dataabse with all columns set as not allow zero length string and when I insert a records in which one of the column is null value it show allow zero length string error any idea how to create a code in visual basic in which allow zero length without change the configuration of the database?
For example my record have job_no name station 1 des 2 albert so I need to pass job number 1 to my access database but came out with error zero length string off course my access database is set no all to do so but I have my reason is that any sample code to force to accept blank strings?
I have searched all over the forums and not found an answer to my question. My question is how do i write to an access database at runtime. The database is also created at runtime. I have a dataset loaded with a table that i needs to be written to the database. how would i write each row of my dataset to my database? Sorry if this sounds a little jumbled together it is late and i am tired. If it is unclear you can ask me and i will answer any questions you have about my question.
View 14 Repliesso I have added a database with 3 columns uniqueID, Site, and ServerI have displayed a site list from the Site column in a comboboxI want to set a variable based on the selection in the combobox
View 14 RepliesI am doing a lab where you have to connect to the database using the Database Configuration Wizard in Visual Basic (Visual Studio 2008). The database connection is there since the form will display the records.The problem is the user is supposed to be able to click on the combobox arrow to select a stock rating (high, low, etc) and then the listbox will display only the stocks with that rating. I thought this would work but nothing is showing up in the listbox.
' strSql is a SQL statement which selects all the fields from the Team database.
Dim strSql As String = "SELECT * FROM Stocks"
'strPath provides the database type and path of the Team database[code]...
I have an app I'm working on with multiple forms. One of the forms, frmLocationInfo, has textboxes and comboboxes which are automatically populated based on a combobox selection from a previous form, frmLocations. I've been able to get any changes made to frmLocationInfo's textboxes to save to the SQL database, however, when attempting to select a different item from any of its comboboxes, it's not saving to the database and instead, I receive a "Procedure or function...has too many arguments specified" error.
Here is the code for the Save button:
'Save changes to Locations db
Private Sub btnSaveClose_Click(ByVal sender As System.Object, ByVal e As System.EventArgs)
[code].....
I use vb2010 to create a simple windows form.I have a checkedcombobox which gets its items from a column (titles) from a .mdb database (this works). When I check an item or multiple items in the combobox, I want to display (multiple columns) the title and for example info in a datagridview.
View 2 RepliesI Have two listboxes , Listbox1 and Listbox 2 , I want to select some items from listbox1 to listbox2 , with those selected items in listboxe2 I want it to extract specific data concerns to those selected item from Microsoft Access and later.I want to use only those specific extracted data to calculated some mathematical function.
View 2 RepliesI use vb2010 to create a simple windows form. I have a checkedcombobox which gets its items from a column (titles) from a .mdb database (this works). When I check an item or multiple items in the combobox, I want to display (multiple columns) the title and for example info in a truedbgrid.
View 1 RepliesI want to add a null binary field in Database.[code]...
View 2 RepliesI am trying have a data grid selection populate a form. I am new to this.Basically I have a connection persistance object and I would like to call that and call a stored procedure with the value of the selection. The datagrid is bound to an object.
[Code]...
I have a listbox (20 Items) with multiselection and label that disply the selection and one button. So I wrote (it works fine)
[code]...
Now when I click on button the label show lets say Item2,Item5,Item10,How do I take off the last ","
somthing like that Item2,Item5,Item10
I used to do: Dim s As String = Trim(Label1.Text)Label1.Text = s.Substring(0, s.Length - 1) but it give me an error converting intiger to string
Working on a project that contains a listView (populated from a database already) and several textboxes. What I am trying to do, and cannot figure out, is to program this so that when a user makes a selection in the listview, it hits a specific database, and based on certain values within that databse, the textboxes are populated with things such as name and address, etc..
View 2 RepliesThe user will basically be able to select a file on their hard drive, and enter some details or info about the file and then save it
View 2 RepliesI have a program that reads a database file(.csv or.Txt) then allows user to select data from 6 different comboxes and taext boxes are then populated based on the selection made from combobox
I would like to be able to give the user the option to save their settings so next time the program is open it will connect to the same database as the last connection and also have comboboxes go to the last selection Do I have to create a save setting value for each combobox? and the connection string?
is there a simple way to just save everything? so when the program is open it goes back to the last time it was open.
osheet.Range("A1").Select
'The line below is the one I would like to know how should I write it in VB.NET:
osheet.Range(Selection, Selection.end(xlDown)).Select
[code]......
I know I'm being an idiot here and I just can't work it out. But i'm trying to take some data back from a vb.net database. It's falling over with a Object reference not set to an instance of an object error. And before the code runs it's saying the variable is being used before it's set, but I can't see how. Code:
Private taNotifications As dsDataTableAdapters.NotificationsTableAdapter = New dsDataTableAdapters.NotificationsTableAdapter
Dim notification As dsData.NotificationsDataTable = taNotifications.GetDataByClientID(userrow.UserID)
If notification.Rows.Count > 0 Then
Dim notificationrow As dsData.NotificationsRow
Dim forwardURL As String = notificationrow.ForwardLocation
End If
It falls over on the Dim forwardURL As String = notificationrow.ForwardLocation
Considering that Grade.firstExam, Grade.secondExam, and Grade.finalExam are all TEXT and not numbers, i can't get the exact solution to convert null values into Zeros. I already tried to use NZ() but it returns an error message (Undefined Function 'NZ' in expression)im using VB.net with MS Access as my database. i also imported System.Data.OleDb Namespace.
[code]...
How can i convert empty string or null that exist in the field?
Is their a more elegant way to assign a space to a value, if a database call returns null for a data set column? I am doing the following check which is pretty tedious:
If (ds.Tables("employee").Rows(0).Item("txtNamePrefix").IsDBNull(0)) Then
txtNamePrefix.Text = ""
Else
txtNamePrefix.Text = ds.Tables("employee").Rows(0).Item("txtNamePrefix")
End If