How to detect if an ASP ComboBox is blank.empty - asp.net

I have an ASP ComboBox that is populated on page load with a list of information and a selected index is set. I want the user to be able to type a new value into the box and run a routine that saves that value.
So far, I've managed to set it so when you run the save routine it can detect the text of the box using;
cboFreeBody.SelectedItem.Text
If the box loads with 'arm' and I change it to 'leg', when I run my routine it grabs the new value and processes it, however if I delete 'arm' and leave it blank when I run the routine the above code returns 'arm', where I'd expect it to return ''.
I'm sorry if I haven't explained myself fully here, I'm rather new to ASP and VB.NET so I'm probably just splurting useless information here, but any help would be greatly appreciated.

I ma not sure but thats might help you..
If com_box.SelectedItem = vbEmpty Then
MsgBox("its empty")
End If

I use the isnullorwhitespace function usually.
if string.isnullorwhitespace(cboFreeBody.SelectedItem.Text) then
else
end if

Related

How to update mark a form dirty after a server side modification

I don't understand how to make the Client ui aware of a server side change in a document.
My use case is the following : I'm adding a button to my form, that calls a custom document method :
In MyDocType.py, I have :
class MyDocType(Document):
#frappe.whitelist()
def change_some_value_in_doc(self):
self.the_field_i_want_to_change = 50
It work in the sense that the_field_i_want_to_change is immediately updated to the new value.
However, If I hit Save, I get the message "No changes in document". I managed to determine that this is because on the JS side, the form is not marked as "dirty", but despite reading the documentation over and over, I cannot find the right way.
I tried with self.notify_update() which seems to have no effect.
Is it a bug ? Or am I misunderstanding how this is supposed to work ?
I'm using frappe v 14.0.0-beta.3
[EDIT]
Actually, I realized that doing
class MyDocType(Document):
#frappe.whitelist()
def change_some_value_in_doc(self):
self.the_field_i_want_to_change = 50
self.save()
Does work in the sense that it save the new value, but it's not exactly what I'm looking for, because my purpose is actually to pre-fill some data with the custom method and leave to the user to complete before saving...
Any help to get me in the right direction would be very appreciated.
To pre-fill data in your form - that you want the user to confirm before saving to the database, you should use client-side scripting (in JS). Changing the value on the server is not going to help you since you want the user to get pre-filled values before inserting a record in the database.

Hiding LinkButton

In VB.NET, I have a LinkButton that, when clicked, creates a report. We want to disable this functionality based on whom is logged into the system. I have a session variable to indicate whether this should be visible or not but when I set idLinkButton.visible = False, it has no effect. Any ideas on what I need to do to be able to turn this on and off?
'code-behind
' in page_load
If Not Convert.ToBoolean(HttpContext.Current.Session("HideReports")) Then
PDFbutton.Visible = True
Else If Convert.ToBoolean(HttpContext.Current.Session("HideReports")) And HttpContext.Current.Session("LoadFromConsole") Then
PDFbutton.Visible = True
end if
First, have you tried setting .Visible = false outside the if/then logic?
If that works, then you want to troubleshoot the logic. Add my first line to what you show above, then change your first line to my second line.
Dim hideRpt as Boolean = Convert.ToBoolean(HttpContext.Current.Session("HideReports"))
If Not hideRpt Then
Now put a breakpoint on the "If Not..." line.
If you aren't getting what you expect, add another line to get a string for the session value, to make sure it really should convert to a bool.
Basic troubleshooting, man, break it down into smaller parts. Sometimes I'll start a fresh windows app just to have a blank slate on which to work out details.

how to use QTable::editCell()

I don't understand how QTable::editCell() should be used. I am trying to do some error checking based on entries made by user in a QTable as mentioned in my another question.
I would like to give user an opportunity to re-edit the cell which has error. For example, if name column entry has some special characters such as '(', the user should be prompted for the error and the control should go back to same cell in edit mode. I tried using QTable::editCell() in my code as shown below.
Table->editCell(row, 0, TRUE);
name = Table->text(row, 0);
However, this doesn't work as expected. The control doesn't stay in the cell at all and obviously the name is not correctly collected. So, my question is how to ensure from within code that a cell of QTable can be edited so that the edited contents can be accessed immediately in next statement (as shown in above code).
Note: I am working with qt 3.3.8 only.
I don't think you can do that. You'll have to go back to the event loop, and wait for one of the signals (like valueChanged(row,col)) to be fired to re-validate the data.
A blocking wait on a GUI object is often not a good approach (except for modal dialogs).
I know I'm a little late here but you should use the following connect statement with your own custom function to do your specific needs such as below. You can also use this method to disable users from entering in special characters within you custom function. That way they wont ever have to correct undesirable characters.
connect(ui->tableWidget, SIGNAL(cellChanged(int,int)), this, SLOT(customFunction(int,int)));
void updateTable
{
//remove invalid characters
}

How to view Session Variables in Visual Studio 2008 Debugger?

Usually using Visual Studio's debugger is a breeze. Scanning through Locals quickly shows the values of variables, etc. However, I'm at a loss how to find out the values contained in session state variables? Can anyone give me a hand?
Let's say I put a breakpoint right after:
Session["first_name"] = "Rob Roy";
How do I view the value contained in Session["first_name"] from locals?
It's pretty simple to inspect the session during debug. Just put a breakpoint in your code and just highlight your Session code (eg. highlight: Session["first_name"]) then right click and select QuickWatch....
This will setup up a watch on your Session for the value you had defined. You can also inspect other Session elements by adjusting the Expression field in the QuickWatch window and clicking the Reevaluate button.
In VS you can just put 'Session["first_name"]' in the Immediate Window and execute while the code is running. That will return the value that it holds.
If you can't find it go to: View > Other Windows > Command Window, or press Ctrl+W, A
It will look like this:
I know its a bit of a late reply but for anyone else who is interested, I hope this helps!
Isn't it HttpContext.Current.Session("..."), I ask as I haven't used ASP.NET for a long time.

SqlSiteMapProvider - OnSiteMapChanged event never fires?

I'm doing the Wicked Code implementation of SqlSiteMapProvider, except in VB.NET.
There's a few things with the code that are causing issues, and I don't understand how it is supposed to work the way it's written in the article. I've provided the code straight from the article provided below. I've pasted the code here for ease of viewing
First issue - the depedency is instantiated BEFORE (lines 134-137) the tree is created (151-160) - so as soon as you add the depedency to the http.cache (165-167), the OnSiteMapChanged event (242) fires immmediately - making the entire proccess run again - and this loops many times until finally something makes it stop. (i stepped through it and counted the code looping at least 20 times before I gave up on trying to guess when it hit last)
OK, so to fix this I just moved the code to the create the dependency to AFTER the tree is built, right before inserting to http.cache (so HasChanged property is false when adding to http.cache, and you don't get stuck in this psuedo-ifinite-loop).
I still have a problem though - every time a page loads, the BuildSiteMap() hits and line 121 checks if _root is not null - it seems it is never null after it is first built... this is good because I don't want to hit the DB each time. Now, I insert a record into the table... the OnSiteMapChanged event never fires. As I browse pages on the app, the sitemap does not reflect the newly inserted record - stepping through the code, I see that the check at line 121 is still causing the function to short circuit... The sitemap will only refresh if i re-start Visual Studio, which causes the private _root field to become null again, and re-builds the sitemap, reflecting the new changes.. (refreshing the browser or starting new browser instances does not work)...
EDIT: THE ISSUE STEMMED FROM A SILLY 'SET NOCOUNT ON' LINE IN THE TOP OF MY STORED PROC. APPARENTLY THIS BREAKS THE QUERY NOTIFICATION. It seems that this statement is seen as a result set and that the second, actual query statement invalidates the result set resulting in a notification. This was very hard to find and nowhere in the MSDN documentation until I added the comment. Hope this saves someone else the miser I went through!
THE ISSUE STEMMED FROM A SILLY 'SET NOCOUNT ON' LINE IN THE TOP OF MY STORED PROC. APPARENTLY THIS BREAKS THE QUERY NOTIFICATION. It seems that this statement is seen as a result set and that the second, actual query statement invalidates the result set resulting in a notification. This was very hard to find and nowhere in the MSDN documentation until I added the comment. Hope this saves someone else the miser I went through!

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