NullReferenceException Was Unhandled Trying To Open A Workbook In Excel 2003?
Jul 19, 2010
I am trying to transfer data from a VB form to an existing Excel 2003 file. This is the code I am using, but it is throwing up the following error:I have coded in VBA but am new to VB.NET and am struggling with setting up the objects
Dim oXL As Excel.Application
Dim oWB As Excel.Workbook
Dim oSheet As Excel.Worksheet
I have a seemingly simple question I can't seem to figure out. I have an old VBA application that connects to a database using OLEDB, grabs data, and populates an excel sheet using Excel.QueryTable after the user clicks a button. I'm trying to port this rather large program to VB.NET. I've created a few projects in my solution, one of which being an ExcelWorkBook. I want this workbook to load each time users launch the program and be blank until they click a button which will populate the data.
I am working with an application, which stores and manipulates data in Excel. have successfully imported the necessary Excel libraries viaImports Excel = Microsoft.Office.Interop.Excel
I think I am trying to do something simple. I am using this command:[URL]..Sometimes VB gets hung up opening the website. If this is the case, I want it to quit trying and move on to the next line of code.
For example, try to open the website in excel for 45 seconds. If still not open, skip and move to next line of code.
I have the following function to read an excel spreadsheet and read a certain cell for a value and then I put it into my own List(of T). Everything works fine. However the one quirk I am running into is that as the "oExcel.Workbooks.Open(ExcelFileName)" executes, it does a "Windows Beep" sound.
I have a program that filters data and then outputs it to a tabg delimited file. I then use Excel Interop to open this file in Excel because directly outputting to a worksheet takes too long. So currently I am using this code:
AD.DF.WriteToFile(vbTab) Dim WB As Workbook = ExcelApp.Workbooks.Open(AD.DF.DatafileInfo.WriteToFileLocation) ExcelApp.Visible = True
The first line takes the filtered data and outputs to a tab delimited file. The second opens that same file in a new workbook in Excel. And obviously the third makes Excel visible. Here is my problem though: right now when this code is run there are two open workbooks. I already have an active workbook and I would just like to open this file to that workbook.
I have successfully created a new excel with the code
[xlApp = New Excel.ApplicationClass]
and can transfer and manipulate data from my VB2008 form back and forth with the spreadsheet One time only each time I try and add additional data it wants to open a new workbook with the same name but cant seem to get it to just add the additional info.
I am finally switching from VB6 to VB Net and am rewriting a technical application that calculates the heat transfer performance of automotive radiators, heater cores, evaporators, condensers, etc.The user can calculate a heat exchanger and save the results to an Excel spreadsheet. After a series of calculations he can then plot curves of performance.
He can also click on a previous calculation in Excel and import it into the VB routine. The user may have a number of workbooks open when he does this.My problem is I need to open the Excel workbook that is the active workbook. I have been able to select the active worksheet but have been forced to specify the index of the workbook. I have not been able to get the workbook I want.. The code I used is the following,
Dim oExcel As Object = GetObject(, "Excel.Application") Dim oBook As Object = oExcel.Workbooks(1) Dim oSheet As Object = oBook.activesheet
How do I get the active workbook instead of Workbooks(1) with an index of 1?
I have questions on this [FAQ's: OD] How do I open an existing Excel Workbook? I have playing around with the code little. Trying to mod the code to display the selected path and File name in the textbox I have on a form. I can to get it to work right
I'm writing a VB.NET WEB application and I'm fairly new at it. What I want to do is open Excel workbooks on the client workstation so the user can "Save As" or print or basically do whatever they want with it past that point. I've done this in a windows application using System.Diagnostics but all the information I've read so far doesn't seem to work. I can open .txt and .xls files using this approach:[code]but it opens in the browser, which is not what I want. Do I need to mix Javascript with the HTML and the VB code?
here is a copy of my current code. Am trying to open an existing Excel spreadsheet then retrieve the old balance data refigure the new balance and store new data into the spreadsheet. Am I on the right tracK, or way out in left field?
In building an Excel workbook with VB.Net, is it possible to sort all the worksheet tabs into a particular order? I'm building a workbook with individual sheets named by drive letter, i.e., "C Drive", "D Drive", etc.
This never happened to me, and the less data one has (usually) the less you can say what happened.I am trying to write a simple query analyser. I randomly receive these kind of crashes:
[Code]...
The file specified above does not exist. The place where it crashes is wrapped with Try-End Try. Moreover, yes, I have the painting event set up but it should not concern it (or maybe it does?). I have to add that I use visual basic express edition. The error occurs ocasionally - sometimes when I'm lucky nothing happens, and when I'm not then I get this crash.
This is driving me slighty madder than i usually am. The thing thats bugging me is the EXACT same code works in a test project i did with an sdf database.See my comments in the code
vb Private Sub tbScan_KeyUp(ByVal sender As System.Object, ByVal e As System.Windows.Forms.KeyEventArgs) Handles tbScan.KeyUp
I have made a tic tac toe board and when i go to debug the application i get a "NullReferenceException was unhandled". this happens diring this part of the code:
on Form1, i have a combobox1 where i have 15 values. im using a case statement with those 15 values to decide what is the next form to go to. i need to make sure the user cannot add in his own text to it or click the NEXT button without having any value at all. how do i add these "exceptions" to my code?
i would think any exception would go before the case so that it could tell you didnt put in the right answer before it looks through the case statment and give you a nullexceptionhandler reference.
I am working on my project with the listbox, I am reading the strings through the text file and split the strings to input them on the listbox.[code]When I selected the item on the listbox, I get the error.Error: Object variable or With block variable not set.
I can't work out what's causing it. The error report says "Object variable or With block variable not set." for the line "allSlotLabels(i).Image = imgCherries". This line is no different from the other, so I guess it's just the error it picked up first after randomly generating the number.
Using Visual Basic 2008 Express Edition, and trying to set up code for an Add button to add a row to an SQL database. The code below is copied from the Help, and modified to reflect the fact my dataset is called Test_SQL_DbDataSet, my table is called Details, and just 2 columns at the moment .. "ID" and "Detail"
Dim newDetailsRow As DataRow = Test_SQL_DbDataSet.Tables("Details").NewRow() newDetailsRow("ID") = "10" newDetailsRow("Detail") = "Maint" Test_SQL_DbDataSet.Tables("Details").Rows.Add(newDetailsRow)
When I select it, I get a "NullReferenceException was unhandled" error saying "Object reference not set to an instance of an object"
Im getting an Error saying:"NullReferenceException was Unhandled - Object reference not set to an instance of an object."I have no idea what this means as a beginner,
Me.FilmTableTableAdapter.Fill(Me.DVDDatabaseDataSet.FilmTable) Dim con As OleDb.OleDbConnection = New OleDb.OleDbConnection("Provider=Microsoft.jet.oledb.4.0;data source=|DataDirectory|\DVDDatabase.mdb") Dim cmd As OleDb.OleDbCommand = New OleDb.OleDbCommand("SELECT * FROM FilmTable", con) con.Open()
I got two forms. Form 1 I ask the user a number of guest Form 2 I ask each guest their name, their age
I decide to make a loop throught form2 array base on the number of guest but then I got this error. NullReferenceException was unhandled.
Private Sub btnBook_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnBook.Click iTest = CInt(txtChildren.Text) Do Until (iCounter = iTest) And (bIsNextClicked = True) PassengersDetails(iCounter).ShowDialog() Loop End Sub
I am new to vb.net 2005 and am desperate in need of solution as I faced error on the following codes.
Public Class Form1 Private PreviousTab As TabControl Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Me.Load
I'm try to use NATUPNPLib to use UPnP to do and automatic port forward in my router but I keep getting and error that I'm not sure how to handle.Here's the part of the code with the error.
Imports NATUPNPLib Imports UPNPLib Public Class Form1
[code].....
I've tried making sure Windows 7 has Network Discovery on and that UPnP in enabled in my router, could it just be my router and how it handles UPnP?