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Thank you for your suggestions! They did in fact point me in the right direction.
Shannon
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I show/hide different forms by defining the forms in a module:
Public Class formLibrary
Public Shared frmMain As Form
Public Shared frmComponents As Form
Public Shared frmNewProject As Form
....
End Class
Then I use the following to close the current form and open another:
Dim newFrmMain As New frmMain
formLibrary.frmNewProject.Hide()
newFrmMain.ShowDialog()
This is working perfect for all forms in my project except one. When I attempt to open the frmNewProject, I get this error:
An unhandled exception of type 'System.NullReferenceException' occurred in Mule! Data Management Tool.exe
Additional information: Object reference not set to an instance of an object.
..on this line of code:
formLibrary.frmNewProject.Hide()
Has anybody ever experienced a problem like this?
Thanks
Brad
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Your form declaration is this:
Public Shared frmNewProject As Form
And you recieve an unhandled exception here:
formLibrary.frmNewProject.Hide()
The reason is because .Hide is not a shared sub procedure of the Forms Class, therefore you are required to instantiate a Form object instance.
For instance:
Public frmNewProject As New Form
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In other words, when you trying to hide a form that does not exist in memory 
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Thanks. That works (anyway it gets me through the code with no exception). But now frmNewProject does not hide. I can't select it but it is still visible.
Any ideas?
Thanks
Brad
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Do you have a code sample of what you have changed and how you are using .Hide? And what do you mean when you say
Brad Fackrell wrote:
I can't select it but it is still visible.
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The class is where my forms are declared:
Public Class formLibrary
Public Shared frmOpenProject As New Form
Public Shared frmMain As Form
Public Shared frmScoringJustification As New Form
Public Shared frmProjectName As New Form
Public Shared frmDatesAndLocation As New Form
Public Shared frmPOC As New Form
Public Shared frmArticulation As New Form
Public Shared frmCollectorsAndNotes As New Form
Public Shared frmComponents As New Form
Public Shared frmPrint As New Form
Public Shared frmNewProject As New Form
End Class
The code that I use to Hide and Show:
Dim newFrmMain As New frmMain
formLibrary.frmNewProject.Hide()
newFrmMain.ShowDialog()
When I execute this, frmMain loads and is active. frmNewProject is still visible (behind frmMain, frmMain is a small form; about 30% of the screen) but I cannot select it or any of it's controls.
Thanks for your help.
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I'm not quite sure why your frmNewProject would still be visible...but the reason why you cannot select it or any of it's controls is because you are showing your frmMain as modal.
Brad Fackrell wrote:
newFrmMain.ShowDialog()
When you use .ShowDialog, you are displaying your form modal, meaning you can not access any other form until you close your frmMain.
Going back to your frmNewProject, where are you showing the form in code? If .Hide is not used, is it possible to .Close the form? Just to make sure it is accessing that line of code.
I did a quick test with your class and placed a .Show and .Hide in two button events. It worked with no problems...so in theory, it should be working for you?
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Anonymous wrote:
where are you showing the form in code?
I have a btnClick that calls:
Dim newFrmMain As New frmMain
formLibrary.frmNewProject.Hide()
newFrmMain.ShowDialog()
...nothing else in the btnClick sub.
Anonymous wrote:
If .Hide is not used, is it possible to .Close the form?
No. I think it goes back to what you said about newFrmMain.ShowDialog() only allowing newFrmMain to be accessable.
In fact, after removing formLibrary.frmNewProject.Hide(), it seems like that line of code is doing absolutely nothing.
I've gone through frmNewProject with a "fine tooth comb" to see if there is anything that could be making it 'hang'...no luck finding anything.
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Try commenting out the newFrmMain.ShowDialog()...does your code execute the formLibrary.frmNewProject.Hide()? Give the debugger a try as well, and step into that line of code. It should be executing.
Also, where did you place the code to display the frmNewProject form? (formLibrary.frmNewProject.Show())? I am assuming you did show the frmNewProject...otherwise, the line formLibrary.frmNewProject.Hide() will execute, but you won't have a form to hide, therefore appearing like it did absolutely nothing.
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Anonymous wrote:
Try commenting out the newFrmMain.ShowDialog()...does your code execute the formLibrary.frmNewProject.Hide()
No. It stays visible and active.
Anonymous wrote:
Give the debugger a try as well
It appears to execute just like any other .Hide that is working properly. The debugger doesn't do much at that line. Is there something specific that I can look for?
Anonymous wrote:
where did you place the code to display the frmNewProject form? (formLibrary.frmNewProject.Show())?
In the form that is displayed prior to frmNewProject I have a btnClick with this:
Dim newFrmNewProject As New frmNewProject
formLibrary.frmOpenProject.Hide()
newFrmNewProject.ShowDialog()
Strange thing that I have noticed, after executing the btnClick to hide frmNewProject and show frmMain, I can close frmMain using the 'X' in the upper right hand corner (frmMain_Closed) but the application stays running and frmNewProject is once again active.
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Brad Fackrell wrote:
Dim newFrmNewProject As New frmNewProject formLibrary.frmOpenProject.Hide() newFrmNewProject.ShowDialog()
Does this code work in the form displayed prior to frmNewProject?? If that works, then you have a very strange situation as it is the exact same code when you are attempting to display your newFrmMain.
But...I think the problem is the following:
In your class code you have:
Public Class formLibrary<br />
Public Shared frmOpenProject As New Form<br />
Public Shared frmMain As Form<br />
Public Shared frmScoringJustification As New Form<br />
Public Shared frmProjectName As New Form<br />
Public Shared frmDatesAndLocation As New Form<br />
Public Shared frmPOC As New Form<br />
Public Shared frmArticulation As New Form<br />
Public Shared frmCollectorsAndNotes As New Form<br />
Public Shared frmComponents As New Form<br />
Public Shared frmPrint As New Form<br />
Public Shared frmNewProject As New Form<br />
End Class
Take note of the bold line in your class. Then in your btnClick event you placed:
Dim newFrmMain As New frmMain <br />
formLibrary.frmNewProject.Hide() <br />
newFrmMain.ShowDialog()
Again take note of the bold. Then in your previous form when you display your frmNewProject you had:
Dim newFrmNewProject As New frmNewProject formLibrary.frmOpenProject.Hide() <br />
newFrmNewProject.ShowDialog()
Now if I am correct, when you are attempting to hide your frmNewProject using this line of code (in your btnClick):
formLibrary.frmNewProject.Hide()
It is executing...BUT it is hiding the frmNewProject in your fromLibrary class...which hasn't actually been displayed to the user. Thus appearing to do abosulutely nothing.
How does that work? You are creating a new (local) instance of frmNewProject and then using the .ShowDialog to display it. So, you can test my theory by changing what you had in your previous code:
<br />
Dim newFrmNewProject As New frmNewProject<br />
formLibrary.frmOpenProject.Hide() <br />
newFrmNewProject.ShowDialog()
Try changing it to:
'Dim newFrmNewProject As New frmNewProject formLibrary.frmNewProject.ShowDialog()<br />
'newFrmNewProject.ShowDialog()
I know I jumped around alot...but the main idea is that in your code you are attempting to .Hide a form that hasn't actually been displayed to the user. This is because the formLibrary.frmNewProject and newFrmNewProject are two different instances.
I hope that makes sense?!?
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Yes, that makes sense. I appreciate all of your help on this.
Brad
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Hi, I currently faced a problem on inserting decimal value from vb .net into SQLCE which declared as money data type. ANyone know how to solve this??
Thanks in advance!
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Hi all,
I'm working with the SoapFormatter class and I can serialize my TreeNode with no problems. But I get the following error when I try to deserialize my content.
System.Reflection.TargetInvocationException
Exception has been thrown by the target of an invocation.
The exception is thrown at the bolded line below:
<br />
Dim lSoapFormatter As New SoapFormatter<br />
Dim lReader As Stream = File.Open(asFilePath, FileMode.Open, fileAccess.Read)<br />
<br />
'deserialize the content<br />
Dim lTreeNode As TreeNode = CType(lSoapFormatter.Deserialize(lReader), TreeNode)<br />
<br />
'close reader<br />
lReader.Close()
The InnerException indicates that I have an InvalidCastException.
System.InvalidCastException: Specified cast is not valid.
at System.Windows.Forms.TreeNode..ctor(SerializationInfo si, StreamingContext context)
The thing that doesn't make any sense is that it is working fine on my machine (the one I developed my application on) but when I attempt to run it on another person's machine it throws this cast exception!? 
I transferred my source code to this machine which is how I found out it was throwing this InvalidCastException in debug mode, but I have no clue how to resolve this!
Any ideas?! Please help!
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I have a dropdown list called ddlstat and I want to populate it with values from a database table called status. The value I want to get from Status table is Status name.
here is the code for ddlstat:
Private Sub ddlStat_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ddlStat.SelectedIndexChanged
End Sub
Does anyone have the code to use to populate a ddl.
Thanks
macca
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im not sure if this is what your looking for but...
<br />
<br />
Private Sub ddlStat_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ddlStat.SelectedIndexChanged<br />
<br />
ddlstat.items.clear<br />
dim i as integer<br />
<br />
For i = 0 To (DataSet11.Tables("status").Rows.Count - 1)<br />
ddlstat.items.add(DataSet11.Tables("employee").Rows(i).Item("Status_Name")) 'status_name = column name in table<br />
next<br />
<br />
end sub<br />
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I have a list of records in a combo box.
How do I get the selected row number e.g.
In combo box have the following
A
B
C
D
If I select C then that is the 3rd row. How do I display that I selected the 3rd row.
Thanks in advance
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see SelectedItem() and SelectedIndex()
hey, did you search a bit?
TOXCCT >>> GEII power
[toxcct][VisualCalc]
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combobox1.selectedindex + 1 = the row number
its +1 cause combobox index starts at 0 so the first item is at index 0 and the last is at count-1
in other words assuming the combobox is called combobox1 and the output is going to be in label1
<br />
Private Sub ComboBox1_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ComboBox1.SelectedIndexChanged<br />
<br />
Label1.Text = "You Clicked On row " & (ComboBox1.SelectedIndex + 1).ToString<br />
<br />
End Sub
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Hi Guys,
Currently I use Office 2003 VBA to develop macros userforms etc for my Excel sheets. I was wondering if it is possible to use vb.net that comes with VS 7 to develop all of the above.
The reason I am asking is that in VBA the controls etc are not as 'nice' as the ones in vb.net and there are more features and so on. Also I realy want to learn VB.net (as I am told the syntax is different and it is more powerful than VBA).
Anyway if someone could give me some basic pointers on the whole issue that would be great.
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hi,
i'm actually using a second winform ("info-form") to show some information after the user clicks on a picturebox.
if i click more than once, several "info-form" will show. i'd like to update the info showed in the "info-form" if it exists instead of creating new ones.
moreover, the info-form topmost option to true and i would like to get it topmost only when my app is active, but this is not really important.
any advice?
thancks in advance
Cheers!
Paolo
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Are you working with an MDI application? Or two completely separate forms?
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thanks for answering me,
it's a SDI application,
actually i can manage this issue declaring the name of the second form and verifying if Info_Form "is nothing" or if "Info_Form.IsDisposed" and then creating it.
do you think it's correct?
thanks again!
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