Visual Basic

Cannot update or delete access database

18-Mar-09 20:07

There's paint program samples that will show you how to do this. You need to store the mouse position in member variables, and then do what danish said, draw them in your paint event.

Except, as you want the line to disappear when the mouse comes up, this is actually a place where the CreateGraphics method of the form is valid, it's used to create a graphics object on which to draw temporary things.

Christian Graus

Driven to the arms of OSX by Vista.

hendrikbez18-Mar-09 19:09

18-Mar-09 19:09

I am trying to update and delete ,but get this error code now, it did work before.

error code == "There is no row at position -1"

My update code

Private Sub btnUpdate_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnUpdate.Click

       Dim cb As New OleDb.OleDbCommandBuilder(da)

       ds.Tables("Blokkies").Rows(inc).Item(1) = TxtLuidraad.Text
       ds.Tables("Blokkies").Rows(inc).Item(2) = txtA1.Text
       ds.Tables("Blokkies").Rows(inc).Item(3) = txtA2.Text
       ds.Tables("Blokkies").Rows(inc).Item(4) = txtA3.Text
       ds.Tables("Blokkies").Rows(inc).Item(5) = txtA4.Text
       ds.Tables("Blokkies").Rows(inc).Item(6) = txtA5.Text
       ds.Tables("Blokkies").Rows(inc).Item(7) = txtA6.Text
       ds.Tables("Blokkies").Rows(inc).Item(8) = txtA7.Text
       ds.Tables("Blokkies").Rows(inc).Item(9) = txtA8.Text
       ds.Tables("Blokkies").Rows(inc).Item(10) = txtA9.Text
       ds.Tables("Blokkies").Rows(inc).Item(11) = txtA10.Text
       ds.Tables("Blokkies").Rows(inc).Item(12) = txtA10.Text
       ds.Tables("Blokkies").Rows(inc).Item(13) = txtA10.Text

       da.Update(ds, "Blokkies")

       MsgBox("Register verander")

   End Sub

I did try to use this, but still get same error

If Not IsDBNull(ds.Tables("Blokkies").Rows(inc).Item("luidraad")) Then
            ds.Tables("Blokkies").Rows(inc).Item(1) = TxtLuidraad.Text
        End If

My delete code

Private Sub btnDelete_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnDelete.Click

       If MessageBox.Show("Is jy seker jy wil die register verwyder?", "Delete", MessageBoxButtons.YesNo, MessageBoxIcon.Warning) = DialogResult.No Then

           MsgBox("Register is nie verwyder nie")
           Exit Sub

       End If

       Dim cb As New OleDb.OleDbCommandBuilder(da)

       ds.Tables("Blokkies").Rows(inc).Delete()
       maxrows = maxrows - 1

       inc = 0
       NavigateRecords()
       da.Update(ds, "Blokkies")

   End Sub

dan!sh 18-Mar-09 19:25

dan!sh

18-Mar-09 19:25

Check the value of the variable inc and check that the dataset is not empty.

जय हिंद

hendrikbez18-Mar-09 19:31

18-Mar-09 19:31

sorry, how do you check the value and that the daataset is not empty

dan!sh 18-Mar-09 19:32

dan!sh

18-Mar-09 19:32

You will need to debug the code. Then use Add Watch or quick watch to find the value.

जय हिंद

Re: Cannot update or delete access database [modified]

_Damian S_18-Mar-09 19:55

_Damian S_

18-Mar-09 19:55

You don't appear to be setting the value of inc anywhere before you try to use it.

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hendrikbez18-Mar-09 20:03

18-Mar-09 20:03

I am new to databse, I don't know how to set the value in the code yet.

I did try this, but it is not working

If inc <> -1 Then

ds.Tables("Blokkies").Rows(inc).Item(1) = TxtLuidraad.Text
ds.Tables("Blokkies").Rows(inc).Item(2) = txtA1.Text
ds.Tables("Blokkies").Rows(inc).Item(3) = txtA2.Text
ds.Tables("Blokkies").Rows(inc).Item(4) = txtA3.Text
ds.Tables("Blokkies").Rows(inc).Item(5) = txtA4.Text
ds.Tables("Blokkies").Rows(inc).Item(6) = txtA5.Text
ds.Tables("Blokkies").Rows(inc).Item(7) = txtA6.Text
ds.Tables("Blokkies").Rows(inc).Item(8) = txtA7.Text
ds.Tables("Blokkies").Rows(inc).Item(9) = txtA8.Text
ds.Tables("Blokkies").Rows(inc).Item(10) = txtA9.Text
ds.Tables("Blokkies").Rows(inc).Item(11) = txtA10.Text
ds.Tables("Blokkies").Rows(inc).Item(12) = txtA11.Text
ds.Tables("Blokkies").Rows(inc).Item(13) = txtA12.Text

da.Update(ds, "Blokkies")

MsgBox("Register verander")
End If

modified on Thursday, March 19, 2009 2:27 AM

Christian Graus18-Mar-09 20:59

18-Mar-09 20:59

You're entering a contest to see who can write the most illegible code ?

Christian Graus

Driven to the arms of OSX by Vista.

hendrikbez18-Mar-09 21:07

18-Mar-09 21:07

now what is the best why do wright this code, I am new and want to get this right.

Christian Graus18-Mar-09 21:40

18-Mar-09 21:40

Like I said, your best option is to let your client know you're not the right man for the job. Buy some books and read them. Learn how to program before having clients.

Christian Graus

Driven to the arms of OSX by Vista.

Christian Graus18-Mar-09 22:18

How could you perform a recursive call for a treeview for two different actions?

18-Mar-09 22:18

I'm sorry, I thought you were someone else.

Break it down into steps. Write code that checks that a table of that name exists, that it has rows, etc. Then step through the code in the debugger.

Christian Graus

Driven to the arms of OSX by Vista.

JUNEYT18-Mar-09 12:11

JUNEYT

18-Mar-09 12:11

Hi,

I have a treeview within directories of all drives including checkboxes (Netframework 2.0) When I check one node the following procedure below checks all the childs of the checked node. Therefore I have called the procedure inside the Treeview1_AfterCheck event procedure. But my aim is also to also check the node which is tagged with a driver name such as (C:\, D:\ maybe E:\ or something else). When I do that I am getting stackoverflow error because of recursive calls. How could you perform both actions at once to check the main node (driver name) and the nodes under the other checked one? Somehow I have to get rid of CheckRootNode procedure. Any sample code will be appreciated.

Thanks.

'
'This procedure checks the root node of any child under it
'
Private Sub CheckRootNode(ByVal GetNode As TreeNode)

    Do While Not GetNode.Parent Is Nothing

        Root = GetNode.Parent
        CheckRootNode(Root)
    Loop

    TreeView1.Nodes(Root.Index).Checked = True
End Sub

'
'This procedure checks all the child nodes of the parent
'
Private Sub CheckChildNodes(ByVal GetParentNode As TreeNode, ByVal CheckState As Boolean)

    For Each xnode As TreeNode In GetParentNode.Nodes
        xnode.Checked = CheckState
    Next

End Sub

Private Sub TreeView1_AfterCheck(ByVal sender As Object, ByVal e As System.Windows.Forms.TreeViewEventArgs) Handles TreeView1.AfterCheck

        Call CheckChildNodes(e.Node, e.Node.Checked)
        Call CheckRootNode(e.Node)
End Sub

What a curious mind needs to discover knowledge is noting else than a pin-hole.

Re: How could you perform a recursive call for a treeview for two different actions?

Christian Graus18-Mar-09 12:43

18-Mar-09 12:43

Your issue is that the event fired when the check state changes, is setting the check state. Add a boolean, and use it to stop the event fired in CheckChildNodes from causing CheckChildNodes to be called again from the event handler.

Christian Graus

Driven to the arms of OSX by Vista.

open file directory

captainmogo18-Mar-09 7:06

18-Mar-09 7:06

This is probably a newbie question and I am just not getting it today but... I just want to open a file directory so that the user can open a text file but I dont need to use it in the program. The main form has a button called 'LogFiles' and when the user presses it, I just want it to open the directory and do nothing else. I was using OpenFileDialog but that is stopping execution until a file is chosen. Am i missing something obvious. Thanks

iamalik18-Mar-09 7:26

iamalik

18-Mar-09 7:26

You can use FolderBrowserDialog for this purpose

captainmogo18-Mar-09 7:52

18-Mar-09 7:52

Thanks for the reply,

I looked at the folderbrowserdialog as you suggested and it seems as if it does the same thing. I cannot do anything else on the main form until i select a folder or press cancel. That is not exactly what I was going for. Instead of putting a shortcut on the desktop the the application log file, I wanted to open the folder from a button on the front panel. If the folder stays open in the background, the application doesnt care. Is this not possible.

iamalik18-Mar-09 8:03

iamalik

18-Mar-09 8:03

I guess you want to the browse to the some path when LogFiles button is clicked.
You need to set SelectedPath property FolderBrowserDialog in button click event.

Isn't it

captainmogo18-Mar-09 8:17

18-Mar-09 8:17

yeah thats what I want but I was hoping it could display in the background. Both the folderbrowse and openfile dialog open as modal, it seems, preventing me from doing anything else on the form. I was hoping maybe the folder could open and just sit in background in case the user needed to open one of the files at a later time. I thought there might be a way to do it that didnt require opening an actual file/folder from within the code. Is that not typical?

iamalik18-Mar-09 8:36

iamalik

18-Mar-09 8:36

I am cofused with Background. If you dont want to show to dialog box than you need to save your log file path in some variable. Nothing else

tech60318-Mar-09 14:56

tech603

18-Mar-09 14:56

What you want to do is utilize the background worker process. This will allow you to open the dialog in its own thread not affecting the main form. I have done this for an application for saving or zipping files. I found that if i did not use the background worker process my form would lock up until the save/zip was completed. I found this article very helpful.

http://msdn.microsoft.com/en-us/library/system.componentmodel.backgroundworker.aspx[^]

Hope that helps.

Matthew Vass
QA Analyst
mvass@hostmysite.com
http://www.hostmysite.com?utm_source=bb[^]

Luc Pattyn18-Mar-09 8:31

Luc Pattyn

18-Mar-09 8:31

Hi,

I see three ways of getting a look at a directory:

1. use an existing folderbrowser dialog; since it is a dialog, it will have modal behavior.

2. open up the folder using Windows Explorer; use Process.Start(fileName) to make it happen. This launches a separate process and will behave completely independently of your app.

3. write your own Form that somehow displays folder contents, and Show() it modelessly.

Smile | :)

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captainmogo18-Mar-09 8:39

Re: open file directory [modified]

18-Mar-09 8:39

Thanks Luc,

by background, what I really meant was, independent of my application. I wanted an explorer window to stay open regardless of whether or not a file was chosen. I just couldnt explain myself properly.

Process.Start was just what I was looking for!

Alan N18-Mar-09 8:54

Alan N

18-Mar-09 8:54

Hi,
I think that you want to open a Windows Explorer window at a particular directory for the convenience of your users, correct?

In which case use

System.Diagnostics.Process.Start(pathname) [EDITED typo]

The Start method has many overloads and this simple one uses the associated application to open pathname.

So as an example, if pathname is d:\logfile.txt then Notepad is used to open the file d:\logfile.txt.

What you might not have realised is that directories are associated with Explorer. As a consequence if pathname is a directory, e.g. d:\logfiles then the Start method will open an Explorer windows at the d:\logfiles directory.

Alan.

[EDIT: Like Luc said a few minutes ago]

modified on Wednesday, March 18, 2009 4:09 PM

captainmogo18-Mar-09 9:04