Code:
Private Sub RandomID()
Dim conn As MySqlConnection
conn = New MySqlConnection
conn.ConnectionString = cnString
conn.Open()
[Code] ....
I am getting error here
LastID = comm.ExecuteScalar()
When db is empty, but if db has records it is working fine.
I try to compile a project with msbuild.exe I have this error :
vbc : error BC30136: Error creating Win32 resources: Error reading icon '"Recycle Bin Empty.ico"' -- The filename, directory name, or volume label syntax is incorrect.
This icon is the Application icon which is in the same directory of the project.vbc is started with /win32icon:"Recycle Bin Empty.ico" parameter.Don't know why MSBuild can't reach the file.
I 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 RepliesI have a couple of modal popups on my page that hold checkboxes. The checkboxes are different items that can be added to a specific product. Some products, however, have all of one type of item assigned to them. I need a way to show a message in the modal when the modal is empty.
I have tried using a Label inside the modal that says "All features are currently associated with this product." But the label leaves a space in the modal when it's visibility is set to hidden and that was annoying so I ditched that idea.
What is a good way to have a hidden message that shows up when the modal is empty?
<asp:LinkButton ID="FeatureButton" runat="server">Feature</asp:LinkButton>
<asp:Panel ID="FeaturePanel" runat="server" CssClass="modalPopup"
Style="display:none">
[Code].....
To make it clear this IS homework, however this is also a method of research. i only ask when i get in binds i can not find answers to in other forums . There are so many i could spend more time[code]...
View 2 RepliesSTEP 1: I backup the database using this code snippet (It works fine)
Public Shared Sub BackupDatabase()
Dim sConnect As String = My.Settings.LICConnectionString
Dim dbName As String
[code].....
At run time my application gives an error of "Conversion from type "DBNull" to type "String" is not valid. In my form only one field - Add_info is an optional field which might be filled or not by the user. Before, I had an error when an apostrophe was used so i updated the code as highlighted below. This in return removed the apostrophe error but generated an error whenever there is an empty additional field.
For irow = 0 To QryColSentDataGridView.Rows.Count - 1
If QryColSentDataGridView.Rows(irow).Cells(3).Value = True Then
Try
query = "UPDATE gprdsql.TblCollections SET system_time = '" & _
Labeldate.Text & "' where prac_no ='" & _
[Code] .....
i have a form with 4 text boxes on them when the user selects add the information from the textboxes saves to my database im just wondering does anyone know how i would make an error message appear if one of the textboxes was blank and stop the new data being saved until all textboxes have data in them?i did write the following peice of code but it did not work Private Sub Button1_Click(ByVal sender As System.Object, ByVal e_
[Code]...
When im using a loop in my program and i'm trying to use an Error Provider to pop up whenever a textbox in my groupbox is empty for some reason I cannot get it to work, can anyone tell me what i'm doing wrong?
For Each ctrl As Control In GroupBox1.Controls
If TypeOf ctrl Is TextBox Then
If CType(ctrl, TextBox).Text = "" Then
[CODE].............
I'm not receiving any type of error, it's just that when a textbox is blank the error provider is not doing anything.
what is code i should use if i want to prevent user not to leave empty word in text box after user click save button.Oh ya, i am using visual studio 2005, databse sql 2005 .Here is my code
Private Sub btnregister_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnregister.Click
If MsgBox(" Are You Confirm", MsgBoxStyle.YesNo) = vbYes Then
[code].....
i have 3 listboxes and a calculate button and a lblGrandTotalCost, the program works like this when i select an item from listbox 1 and listbox 2 then click "calculate" it shows a result in listbox 3, after repeating this rocess few times if u click the lblGrandtotalCost button it calculates the grand total of all the totals that are in listbox 3, Now i want the program to show an error message if some one click the lblcalculateGrandTotal button when listbox 3 has nothing in it or empty. how do i do that?
i wrote this code but it don't seem to work
If lstGrandTotalCost.Items = "" Then
MessageBox.Show("warning! theres nothing in listbox 3", "Warning", MessageBoxButtons.OK, MessageBoxIcon.Warning)
I am a newbie using Visual Basic 10 (Visual Studio 2010) and I am having a hard time working with my database. I have a table, let's say, TableEmployee with Fields Name and Position. On the Position Field, some of the records there were empty.My table is displayed in a datagrid and what I want to do is to insert a code that will identify whether the record under the position field is blank/empty and if that condition is true then display a messagebox that says "the particular record is empty"
View 7 RepliesAdding a records with ms access.if my form load is empty in my textbox and press ok button will show a message box "Records Failled".I'll try to run it and i got an error "Data type mismatch in criteria expression." [code]
View 10 RepliesI have a database with lots of fields, some of which are still empty and are to be filled in at a later stage. Is there any way of writing an IF statement (or any other method) that will allow these empty records to be 'shown' in my textboxes in Visual Studio, without receiving the error:
Conversion from type 'DBNull' to type 'String' is not valid.
I'm using visual basic to code a program to help with weights and center of balance on aircrafts, as I'm my unit's new air load planner. The math isn't hard to do, it's just that much of it is trial and error, and redoing all the arithmetic over and over again until the aircraft's C/B is in acceptable limits can eat some time up. So, since i'm trying to learn programming I thought this might be a good way to use it for a real-world scenario.
[Code]...
I have the following form and I'm trying to add a error to the page that if the recordset = 0 then there is a message on the web page stating that there were no results. What's the best way to do that?
Imports System.Data.SqlClient
Imports System.Data
Partial Class _Default
[code].....
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]...
This May sound strange but I have about 10 Visual Basic book, including two references that don't explain this property. It is mentioned but there are not examples as to how to use it.
I just came across this property MaskCompleted but I am not sure how to apply it so that MaskedTextBoxes are not left empty or a message is generated.
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 "".
How to tell the program that if the field is empty to skip it and go to the next step. I have tried IsEmpty (but it tells me the variable IsEmpty was not declared), I have tried to use different If statements but in most cases I get the message
"Conversion from type 'DBNull' to type 'String' is not valid."
I tried using an integer variable and setting it to
'Test = CStr(dt.Rows(I)("socSecNumber")).Length'.
It works for the first step (which makes sense b/c socSecNumber is never empty), but when I set the 2nd and 3rd ones
(TestFName = CStr(dt.Rows(I)("firstName")).Length TestLName = CStr(dt.Rows(I)("lastName")).Length If TestFName > 0 And TestLName > 0 Then...)
Then I am back to getting the message
'Conversion from type 'DBNull' to type 'String' is not valid'.
I do not know anything about recordset and when I did try to use it it displayed the message something like 'get and set are no longer allowed'.
The entire function is below:
Private Sub BtnCreateLetter_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles BtnCreateLetter.Click
Dim SSN As String = TxtBxSSN.Text
Dim dt As New DataTable()
[Code] .....
Is it possible to include something in the SELECT from table? Such as:
"SELECT * FROM" & Students & "WHERE" * NOT DBNull
or
I do not know if it is possible to use variables in the SELECT from table code but if it is I thought perhaps could make a variable named FieldContents and pass it to a function that would do something like:
"SELECT * FROM" & Students & "WHERE" * FieldContents LIKE '[A-Z]'
what is code i should use if i want to prevent user not to leave empty word in text box after user click save button. i am using visual studio 2005, database sql 2005.
View 2 RepliesThe problem I have is that many times, the dataset that this control is bound to is empty. Therefore, the user continuously gets an error saying that one or more fields is missing. When I debug the code, I can see the code in the class loop through all of the radio button controls on the form. Since none of them match the field from the database, the code throws the error. I assume the code expects a match.
Should I modify the class to handle the case when there is a DBNull value? If so, what would be the best method? Or should I approach this situation in a completely different manner?
Public Class myGroupBox
Inherits GroupBox
Private _myTag As String
[Code]....
I'm having an issue with the startup of my build app with vb2010.Let me explain what the situation is at the moment.
I have a form and a splashscreen. I use the application events (startup event) to check if there is a network connection, if so the splashscreen will run and it will check if the database is available, if this is the case, it will copy the online database to the local ms access database.If the startup check of the network is false, it the user gets a message that there isn't any network available and the program will try to run normal, then when the user clicks the ok button of that message, it will check if the local database has any records. If so the splashscreen will run and the program starts normal (without copy the database, because there isn't any network available).The issue that I am having is, that when there isn't a network connection and the local database is empty, (I do get the message that the local database is empty), but the program still runs, while it should exit.Here is the code of the application event:
Protected Overrides Function OnInitialize(commandLineArgs As System.Collections.ObjectModel.ReadOnlyCollection(Of String)) As Boolean
Me.MinimumSplashScreenDisplayTime = 5000[code]......
With this one..
SaveFileDialog2.CreatePrompt = True
SaveFileDialog2.Filter = "Text (*.txt) |*.txt|(*.*) |*.*"
txtBrowse.Text = SaveFileDialog2.FileName
[CODE]...
I'm trying to export the data from dgv to csv txtfile but i'm getting this error..Empty path name is not legal.
I am using VB .Net to connect to an access databse when using several connection sometimes i get this erro "unspecified error microsoft jet database engine" even though i am an administrator on my local machine.
View 1 RepliesThe problem is that if you never enter anything into a cell for a new row then that cell is never validated. This is a problem because I have columns that should not be null. I am doing the check in the row level validation and storing the information about which cells are empty that should not be empty. The row level validation works fine and the row level validation error indicator goes on,(red exclamation mark at the beginning of the row) but I also need a visual indicator on the individual cells that are in error.
I am thinking that setting the HasError property for the cells that are in error should cause them to display n error style (the default red border). Is there a way to this this either from XAML (perferably) or from code?Alternatively I could cause those cells to re-validate when the row editing is finished. Does anyone know how to do this?
If I write the following inside my class,
<DefaultValue(Guid.Empty)> _
Public Property KeyValue() As Guid
I get an error on Guid.Empty "Constant expression is required."
What I'm trying to accomplish is to get rid of this line that shows up in the Designer file,
Me.TestUserControl1.KeyValue = New System.Guid("00000000-0000-0000-0000-000000000000")
I can avoid running the property's Set code with some conditionals on the Value sent when the form instances. I was just wondering if there's a way to deal with it similar to other data types.
Using VB.Net If the grid cell value is empty, i am getting error as "Conversion from string "" to type 'Double' is not valid"Code (gridview_CellLeave)
Dim z1, z2, z3, z4 As Int32
If grvList.CurrentRow.Cells(1).Value <> "" Then
z1 = grvList.CurrentRow.Cells(1).Value
End If
If grvList.CurrentRow.Cells(2).Value <> "" Then
[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 timer that runs every time by itself, and for the code the runs in it I would like to have it clear the dataset before it does anything, the timer runs every 10 seconds, so I tried to do dataset.clear but it would crash if the dataset had no values
View 4 Replies