Populating a datatable from Access gives me this exception where a record has an empty field. How do I handle it?
System.InvalidCastException was unhandled
Message="Conversion from type 'DBNull' to type 'String' is not valid."
I have the following code: tb_Job_No.Text is a combobox
This is the code: Public Sub RepCD_process() ssql_Job = "SELECT * FROM Rep_Dist" ssql_Job = ssql_Job + " WHERE (Job_Number = '" & tb_Job_No.Text & "') " Dim Main_Form As New Main_Form [Code] .....
Can't seem to get pasted this, when it is remark out all works. How to correct this and get data into the listview?
I'm trying to add a new record to my database but i keep getting the message - "conversion from type DBnull to type string is not valid". I think its something to do with the Employee ID when VB attempts to save it to the database my code is below
Imports System.Data.OleDb Public Class Add Private Sub DisplayRow()
Error 1Server Error in '/ Application. -------------------------------------------------------------------------------- Conversion from type 'DBNull' to type 'String' is not valid. Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code. Exception Details: System.InvalidCastException: Conversion from type 'DBNull' to type 'String' is not valid. Source Error: Line 64: Line 65:
I was tried to get quantity from db make use of the selection in list box. I got answered with listbox1. If i selected the item in listbox1 the quantity would appear in textbox1. But in this same code will not work for listbox2 with textbox4.. Here i given the code...
$Con.open() $Dim cd as new oledb.oledbcommand("Select Quantity from tlist where tool_name"& "'"listbox2.selecteditem & "'" & "", con)
[Code]....
Here i got the error as "Conversion from type DBNull to type string is not valid"
I've been getting this error when pulling data from a recordset. It is coming from a null entry and as a newbie to VB2008 I'm not sure how to get around this.
here is my code lblShipping.Text = reader("CARRIERCODE")
the error:Conversion from type 'DBNull' to type 'String' is not valid. Basically what i'm attempting to accomplish is to see if there is anything in that field. If so put it into the text box if not leave it blank.
I use following codes to retrieve data from table, but get error Conversion from type 'DBNull' to type 'String' is not valid.
str = "Select * from gpass where vou_no= " & Val(Me.txtGat.Text) & " And Date = '" & Me.txtDat.Text & "'" dt = GetTable(str) If (dt.Rows.Count > 0) Then
I am importing an Excel spreadsheet, turning it into a dataset and inserting the results into SQL Server (only 100 rows).
I am having an issue with one of the date columns in Excel, which can have a value or not. The "F" column is the one that may be blank and this is the error I get: Conversion from type 'DBNull' to type 'String' is not valid.
How can I add a check to the Dim F As Date = CDate(row(5)) to handle a null?
VB ' The use of letters instead of ' more descriptive variables is ' strictly for this sample peice
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. [code]
Im trying to check a specific item if its already expired. And for some reason, im getting this error "Conversion from type 'DBNull' to type 'String' is not valid."
I am pulling records from an access database onto my form and have a "Next" button to get to the next record, but every time it gets to the 5th record, the error msg, "Conversion from type DBNull to type String is not valid." because one of the text boxes (fields) from the database is empty.
I am pulling data from a local MSSQL database using a stored procedure, then send the data to a web service. Every part of the component works well except for a pesky problem will a DBNull being returned from the DataRow field, when I know that the field is not null and has valid data. The database and associated INSERT statements that add to this field are designed to not allow NULL entries. When I debug break the program on or right before the line that throws the error I see that the field has valid data for the current row.If I add a null check to the code (as below) the operation continues as normal:
Dim dataResultsTable = Me.myViewTableAdapter.GetData(int) For Each myDataRow In dataResultsTable.Rows If worker.CancellationPending Then
[code]....
Why is the read operation returning DBNull instead of the data in the database?
EDIT: Just to be clear, the operation does return the proper data, but the data is not being saved into the variable.
I'm using a date/time picker control and sending the db value to it. I know that the value is null, but I don't understand why the Picker can't be blank. Is there a way to let it be blank? Or should I set up a way to check for nulls and assign today's date or something just in case?
When I close my form without saving I want to check if the data on my form has changed since the last time I saved the data.This peace of code, which I included at the bottom always worked fine.Except when I compade a DateTimePicker with a null value in the db.Than I get the error "Conversion from type 'DBNull' to type 'Date' is not valid."Probably on this peace of
Me.dtpVrijeDatum01.Value.Date <> CDate(reader("VrijDatumVeld01")).Date Or Me.dtpVrijeDatum02.Value.Date <> CDate(reader("VrijDatumVeld02")).Date Or Me.dtpVrijeDatum03.Value.Date <> CDate(reader("VrijDatumVeld03")).Date Or Me.dtpVrijeDatum04.Value.Date <> CDate(reader("VrijDatumVeld04")).Date Or Me.dtpVrijeDatum05.Value.Date <> CDate(reader("VrijDatumVeld05")).Date Or
The total code to check the changes is:
Private Sub CheckForChanges() LeesCheckboxWaarde(Me.chkFacAdrIsBezAdr, intCheckFacAdresIsBez) LeesCheckboxWaarde(Me.chkPosAdrIsBezAdr, intCheckPosAdresIsBez)
I am using a code to generate an id for a table.But it is giving 'Conversion from type dbnull to type integer is not valid' exception.Now I know that this is due to the table being an empty set.But it works properly if there is already a row in the table. [code] When I click on 'new' button it generates an id pattern in the textbox 't1'.But it gives that dbnull exception first.I am using mysql as backend and Visual Studio 2008 as frontend.Any ideas?
I have a query in my DAL that results 1 item, a date. It's either a date or null. But I get an error when the value is null. Conversion from type 'DBNull' to type 'Date' is not valid. Query
I am getting this exception from the following VB.NET code for only certain months: System. InvalidCastException: Conversion from type 'DBNull' to type 'Date' is not valid.It happens on the line:if CDate(dRow("CompleteDate")).ToString("d") = arrWeekYear(i, 1).ToString("d") Then.If I understand this correctly, then the problem is I am trying to compare some NULL values for CompleteDate to a non-NULL value.However for some of the more recent records, it does not. But I am able to get output from the T-SQL query with same date range and there are no errors; it runs quickly also. And I examined this T-SQL query for both "Date_ Completed" and "Review_Date" NULL values, but either way,"CompleteDate" was always = NON-Null value.So I do not understand how this is happening.[code]When I add this line above the error-causing line above, my report times out for these months.If Not dRow("CompleteDate") Is System.DBNull.Value Then
I updated an MS Access file with data and it showed the data is there. When I tried to retrieve I get this message " Conversion from type DBNULL to type Double is not valid" Below is the code to retrieve.
I have this problem that when the textbox don't have a value I always get this error "Conversion from type 'DBNull' to type 'String' is not valid." [code]...
I am receiving the following error "Conversion from type 'DBNull' to type 'String' is not valid" when checking a textedit control to see if it is empty or more than 1 characters in length.
Public Class CustomValidationRule Inherits ValidationRule Public Overrides Function Validate(ByVal
a user will enter a number, n, which ranges from 1 to 30. they will also enter a "P" or an "S" (sum or product). depending on which was selected, it will calculate the sum or product of the numbers from 1 to n.i'm having a conversion error on line 5 stating "Conversion from string "S" to type 'Double' is not valid." [code]
I now have SQL Parameters set up and I'm using them to save/delete/add my data. This all works well, except when it's trying to save a combobox to the datatable it appears with the error above.Majority of my comboboxes have datasources, and the valuemembers of these are the actual list items, not the ID's of the list items.I'm not sure why this error could be happening, I'm fairly sure I've connected everything to the binding source correctly; I've checked it a few times.Does anybody know what the cause of this could be? I've looked around a bit and I haven't found much
I am getting the error "Conversion from type 'DataGridViewTextBoxCell' to type 'String' is not valid." When trying to display a cell from DGV in a listbox.I have my variable for the cell reference as follows:
Dim a As Object a = DataGridView1(4,1)
To insert it in the listbox as follows:
lstLetter.Items.Add(String.Format(a))
I tried:
lstLetter.Items.Add(a)
This will not actually display the entry inside the referenced cell, it shows this in my listbox instead:
