Null reference exception - Visual Basic Discussion Boards

Re: Is it possible to add multi level sub menu to toolbar [style = Dropdown]

MikeD 229-Jul-11 3:56

29-Jul-11 3:56

if you are using the drop down menu on the MDIform interface (Control E to get into it) then you will notice there are arrow buttons, use the right arrow to indent a menu option which makes it a sub menu of the first entry above it that has a lesser indent

left arrow reduces the level of the menu entry

not sure that was best explanation but try it and you will see what happens

Mike

Retrieving GUID from installation

T.RATHA KRISHNAN20-Jul-11 2:16

T.RATHA KRISHNAN

20-Jul-11 2:16

Hi!
I've created InnoSetup output files for a VB application a long time ago. I lost the script files(.iss files). But I've the output files(Setup files). Is it possible to install the setup and retrieve the GUID(AppId) from the installation? How?

Re: Retrieving GUID from installation

Dave Kreskowiak20-Jul-11 7:01

Dave Kreskowiak

20-Jul-11 7:01

If you're talking about the ProductCode, then this is a script I use by putting a shortcut in the SendTo menu to get it. All I do is right-click the .MSI, Send To -> GetProductCode.

Dim msi,database,view1,record,productCode

Set msi = CreateObject("WindowsInstaller.Installer")
Set database = msi.OpenDatabase(WScript.Arguments(0), 1)

Set view1 = database.OpenView("SELECT `Value` FROM `Property` WHERE `Property` = 'ProductCode'")
Call view1.Execute

Set record = view1.Fetch
If record Is Nothing Then
	MsgBox "Unable to find a ProductCode in the MSI database!"
	WScript.Quit
End if

productCode = record.StringData(1)

Set record = view1.Fetch
If record Is Nothing Then
	RecordsReturned = 1
Else
	RecordsReturned = 2
End If

Set record = Nothing
view1.Close
Set view1 = Nothing
Set database = Nothing
Set msi = Nothing

If RecordsReturned = 1 Then
	InputBox "The ProductCode is:", WScript.Arguments(0), productCode
Else
	MsgBox "There was more than one 'ProductCode' record returned from the MSI database!!"
End If

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Dave Kreskowiak

Printing files in the background

Simon_Whale20-Jul-11 0:23

Simon_Whale

20-Jul-11 0:23

I need the ability to print files out from our application. I can use the ProcessStartInfo to do this in the background with out any issue using the following code:

Dim psi As New ProcessStartInfo()
       With psi
           .Verb = "print"
           .WindowStyle = ProcessWindowStyle.Hidden
           .FileName = "C:\Quote.pdf"
           .UseShellExecute = True
       End With

I also need to be able to change the printer that it uses depending on the reports specified. But I need to be able to change the printer in the background without user interaction

Does anyone know how to change the printer for the print job? or am I going about this the wrong way?

Thanks
Simon

Lobster Thermidor aux crevettes with a Mornay sauce, served in a Provençale manner with shallots and aubergines, garnished with truffle pate, brandy and a fried egg on top and Spam - Monty Python Spam Sketch

Re: Printing files in the background

Dave Kreskowiak20-Jul-11 6:57

Dave Kreskowiak

20-Jul-11 6:57

Change the .Verb to "printto", then add the printer name, preferrably in quotes, in the Arguments property:

.Verb = "printto"
.Arguments = """printerName"""

A guide to posting questions on CodeProject[^]

Dave Kreskowiak

Re: Printing files in the background

Simon_Whale25-Jul-11 22:31

Simon_Whale

25-Jul-11 22:31

Thanks Dave

I tried what you suggested but PDF files can't be printed to a remote printer using processstartinfo as printto isn't a verb that is setup by default when installing the Adobe reader.

Found this out by looking at the verbs in processstartinfo e.g.

dim psi as new processstartinfo("c:\quote.pdf")

for each verb as string in psi.verbs
 debug.print(verb)
next

and by checking this via windows explorer by going into the Tools -> Options -> File Types tab and looking at the advanced properties.

Back to the drawing board for me on this one at the moment.

Lobster Thermidor aux crevettes with a Mornay sauce, served in a Provençale manner with shallots and aubergines, garnished with truffle pate, brandy and a fried egg on top and Spam - Monty Python Spam Sketch

Re: Printing files in the background

Tim Carmichael26-Jul-11 3:14

Tim Carmichael

26-Jul-11 3:14

After reading all of the posts, if you have to print PDF, look into something like GhostPDF.

We have a reporting solution (Business Objects) that has been in place for years. Of late, for WHATEVER reason, reports are now printing with the header and footer information removed.

Since we can save the reports via code in a PDF format, I tried using GhostScript yesterday to print the PDF document to the affected printers. Early results are encouraging.

Tim

Null reference exception

David C# Hobbyist.19-Jul-11 9:38

David C# Hobbyist.

19-Jul-11 9:38

I am working on a data based app. I have everything working to this point. when I go to insert a new record to the table I get a Null reference exception

.

Private Sub StudCount_Compute(ByRef result As String)
           ' Set result to the desired field value

           result = (WallLenght & "  " & Guage.ToString & "  " & "Ga." & "  " & WallHeight.ToString & "  " & "Ft.")



       End Sub

I'm unsure how to fix this, most likely it's a stupid thing I forgot to do.
Please show Me the error of My way's. Confused | :confused:

Thanks

Frazzle the name say's it all

Re: Null reference exception

DaveAuld19-Jul-11 9:54

DaveAuld

19-Jul-11 9:54

frazzle-me wrote:
WallLenght

I don't know about you, but that is not how i spell WallLength.

Not something as simple as that is it?

Dave
Find Me On: Web|Facebook|Twitter|LinkedIn

Folding Stats: Team CodeProject

Re: Null reference exception

David C# Hobbyist.19-Jul-11 9:58

David C# Hobbyist.

19-Jul-11 9:58

Maybe lol typo I'll check D'Oh! | :doh:

Frazzle the name say's it all

Re: Null reference exception

Dave Kreskowiak19-Jul-11 9:58

Dave Kreskowiak

19-Jul-11 9:58

WallHeight, Gauge, and/or WallLength are probably Nothing and not an actual object instance.

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Dave Kreskowiak

Re: Null reference exception

David C# Hobbyist.19-Jul-11 10:04

David C# Hobbyist.

19-Jul-11 10:04

Sadly I also Misspelled it in the Data base(can You see the "L" on my forehead?)
Unsure | :~

Fixing all entries he say's while hanging his head low

Frazzle the name say's it all

Re: Null reference exception

David Mujica19-Jul-11 10:06

David Mujica

19-Jul-11 10:06

Yep. WallHeight, Gauge, and WallLength are not defined or passed in as variables to your subroutine. I'm surprised that it compiles.

Using the debugger, step into the routine and examine the values of those variables. (you can do this by placing your mouse on top of the variable and the tool tip will show you the current value)

Re: Null reference exception

Eddy Vluggen19-Jul-11 10:42

Eddy Vluggen

19-Jul-11 10:42

David Mujica wrote:
I'm surprised that it compiles.

VB.NET

Option Explicit Off
Public Class Form1
    Sub New()
        InitializeComponent()
        Text = CStr(Value_Of_A_Politicians_Promise)
    End Sub
End Class

Bastard Programmer from Hell Suspicious | :suss:

Explicit

David Mujica20-Jul-11 6:29

David Mujica

20-Jul-11 6:29

Yep. I know that it could be done by using Option Explicit Off, but my VS environment has it set to default of "Explicit On".

Back in my days of programming Fortran on the VAX, we used to use some compiler directive which effectively forced you to declare all of your variable. I'm old school that way. Cool | :cool:

Re: Explicit

Eddy Vluggen20-Jul-11 7:35

Eddy Vluggen

20-Jul-11 7:35

David Mujica wrote:
<layer>we used to use some compiler directive which effectively forced you to declare all of your variable. I'm old school that way.

True, that's how things should be. Working without is asking for trouble, giving you a new and empty object when you have a typo in the variable-name.

..and it's not much extra work Smile | :)

Bastard Programmer from Hell Suspicious | :suss:

Re: Null reference exception

Shameel20-Jul-11 9:40

Shameel

20-Jul-11 9:40

David Mujica wrote:
I'm surprised that it compiles.

With 'Option Explicit Off', you're in for loads of surprises. Unfortunately, VB is often very forgiving.

error while converting string xml to xml using xelement

Ankit Aneja19-Jul-11 5:47

Ankit Aneja

19-Jul-11 5:47

Hi All
I am making a string from dataset and then converting to xml.while converting its giving me error unexpected symbol "=" at location

For Each row In dsGetBVItemDetails.Tables(0).Rows
                       strxmlString += _
                           "<ItemDetails>" & _
                               "<Item code=" + dsGetBVItemDetails.Tables
(0).Rows(i)(0).ToString() + ">" & _
                                   "<Description>" +
dsGetBVItemDetails.Tables(0).Rows(i)(1).ToString() + "</Description>" & _
                               "</Item>" & _
                               "<ItemQty>" + dsGetBVItemDetails.Tables
(0).Rows(i)(2).ToString() + "</ItemQty>" & _
                               "<Message>" + dsGetBVItemDetails.Tables
(0).Rows(i)(3).ToString() + "</Message>" & _
                           "</ItemDetails>"
                       i = i + 1
                   Next

It is giving error while converting only when adding attribute "code" in element Item pls suggest

and then converting like this

XFinalXML = XElement.Parse(strxmlString.ToString())

                   xmlResponse = XElement.Parse(XFinalXML.ToString())
                   xmlResponseDoc = New XDocument(xmlResponse)
                   schemaResponse.Add(Constants.TARGETNAMESPACE, AppDomain
.CurrentDomain.BaseDirectory & "Schema\" & Constants.GetBVItemsResponse)
                   nsResponse = xmlResponseDoc.Root.Name.NamespaceName

Ankit Aneja
"Nothing is impossible. The word itself says - I M possible"

Re: error while converting string xml to xml using xelement

Richard MacCutchan19-Jul-11 6:34

Richard MacCutchan

19-Jul-11 6:34

Are you adding double quote characters around the attribute value that follows "<Item code="? You can check this by looking at the generated string in your debugger.

The best things in life are not things.

Re: error while converting string xml to xml using xelement

Ankit Aneja19-Jul-11 6:37

Ankit Aneja

19-Jul-11 6:37

yes below is my code
For Each row In dsGetBVItemDetails.Tables(0).Rows
strxmlString += _
"<ItemDetails>" & _
"<Item code=" + dsGetBVItemDetails.Tables
(0).Rows(i)(0).ToString() + ">" & _
"<Description>" +
dsGetBVItemDetails.Tables(0).Rows(i)(1).ToString() + "</Description>" & _
"</Item>" & _
"<ItemQty>" + dsGetBVItemDetails.Tables
(0).Rows(i)(2).ToString() + "</ItemQty>" & _
"<Message>" + dsGetBVItemDetails.Tables
(0).Rows(i)(3).ToString() + "</Message>" & _
"</ItemDetails>"
i = i + 1
Next

Ankit Aneja
"Nothing is impossible. The word itself says - I M possible"

Re: error while converting string xml to xml using xelement

Dave Kreskowiak19-Jul-11 7:05

Dave Kreskowiak

19-Jul-11 7:05

No, you're not. The resulting string code should be closer to:

<Item code=""" + dsGet... + """>" & _

But, you shouldn't even be doing it this way. You're code is nearly impossible to read and makes it very difficult yo see what's going on. Look at my other reply.

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Dave Kreskowiak

Re: error while converting string xml to xml using xelement

Richard MacCutchan19-Jul-11 9:29

Richard MacCutchan

19-Jul-11 9:29

To add to Dave's comments, you have ignored my suggestion and merely reposted the original code, minus the <pre> tags, so it's almost impossible to read. And it obviously does not include the double quotes; had you used your debugger you would have spotted that fairly quickly.

The best things in life are not things.

Re: error while converting string xml to xml using xelement

Dave Kreskowiak19-Jul-11 7:04

Dave Kreskowiak

19-Jul-11 7:04

You're missing quotes around the value for code.
Concatentating string together to build an XML document is doing it the hard way and it's less forgiving of typos and invalid characters in the contents.

You might want to look into building it this way:

Dim xml As New XDocument

xml.Declaration = New XDeclaration("1.0", "utf-8", "yes")

Dim rootNode As New XElement("RootNode")

For index = 1 To 3
    rootNode.Add(<ItemDetails>
                     <Item code=<%= index %>>
                         <Description>Some description text <%= index %></Description>
                     </Item>
                     <ItemQty><%= index %></ItemQty>
                         <Message>Item Message <%= index %></Message>
                 </ItemDetails>)
Next

xml.Add(rootNode)

Debug.WriteLine(xml.ToString)

Notice that any values are automatically put into quotes when needed. Plus, you get full Intellisense support and syntax checking in Visual Studio 2010.

A guide to posting questions on CodeProject[^]

Dave Kreskowiak

how to make usercontrols in vb6

karaikudiselva18-Jul-11 23:40

karaikudiselva

18-Jul-11 23:40

Hi Every body...VANAKKAM..( good morning or afternoon or evening in Tamil Langauge)..I want to learn the basiclogic to create my own user control.

Please Guide me..

Selvaraj.G

Re: how to make usercontrols in vb6

Nagy Vilmos19-Jul-11 0:22

Nagy Vilmos

19-Jul-11 0:22

In the IDE create a new User Control. Add controls to it and make sure all settings you require are persisted. Apart from that it's the same as creating a form.

You'd be better off learning how to create a controls in a language that hasn't been deprecated and is still supported. Move to .net; C# or VB.net.

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