This may be a simple question, but I have searched quite a few sites and have tried a few of my own ideas and I still cannot seem to find a simple way to get Visual Studio to replace all of the listbox items with the string of nothing with some other text.
Using things such as :
For Each S In ListBox1.Items
S.Replace("", "Not Blank")
Next
Shows:
Error
String cannot be of zero length
Which is quite annoying because the actual listbox item contains no text.
This seems to be one of the easiest things I have ever encountered while using vb.net. But it now seems very hard for what should be a simple command.
A couple of problems. The Replace function returns a new value, and you promptly ignore it. Second, you can't really modify the collection as you For-Each over it, so a For-Loop would be more appropriate.
I think you want something like this instead:
For i As Integer = 0 To ListBox1.Items.Count - 1
If String.IsNullOrEmpty(ListBox1.Items(i).ToString) Then
ListBox1.Items(i) = "Not Blank"
End If
Next
Related
I've been working on a database project for my database classes but I am stuck at the most ridiculous thing; clearing a ComboBox of values in one of my forms. I've been trying to figure out how to do this for hours, but I cannot do it. The ComboBox has a control source linking it to an attribute which is a data type of Date/Time, formatted as short time (hh:ss)
I've tried a few things, but nothing really works, like:
ComboBox1.Items.Clear()
but that won't work because the Items property doesn't even exist in Access's version of VB, I run Access 2019 which has VB for Apps 7.1. Most things on the Internet suggest this approach.
I've also tried a rather quirky method:
index = Combo39.ListIndex
Dim indexc As Integer
indexc = 0
If index = -1 Then
'do nothing because its already empty
Else
Do
Combo39.RemoveItem (indexc)
If indexc = index Then
Exit Do
End If
indexc = indexc + 1
Loop
End If
This code basically loops until the number of times the loop has cycled is the same as the index number of the combo box. I am not sure why, but it doesn't work. It does appear to remove some things, but not everything. It's as if the loop breaks early.
I am in huge need of help, I've run completely dry on how to do this one simple thing. I would greatly appreciate help, thank you.
As your combobox seems to have a list of values as its rowsourcet, all you need is to clear this:
Me!Combo39.RowSource = ""
I couldn't find a solution for this on SO or other source. I apologize in advance if this is a tired question:
I have a macro that iterates through placeholders in shapes. Some of these placeholders have text, some don't. I'm trying to figure out if
.Shapes.Placeholder.TextFrame.TextRange has any value or not (In the 'watches' section of the VBA editor, this property has <The specified value is out of range.>). If it does, do something. Otherwise, continue the For Each statement. However, everything I tried has thrown out of bounds errors or something of that type.
I have tried:
If Not (placeholder.TextFrame.TextRange.Length = 0) Then: Immediately throws out of bounds error
Try/catch, which doesn't seem to exist in VBA (Gives me Sub or Function not registered)
If Not CStr(placeholder.TextFrame.TextRange) = "0" then
I'm quite out of my depth as I don't have experience with any Visual Basic iteration. I just need to, if that property is empty or null, skip over the placeholder.
EDIT: Following suggestions, I tried this:
For Each placeholder In sld.NotesPage.Shapes.Placeholders
If Not (placeholder.TextFrame Is Nothing) Then
If Not (placeholder.TextFrame.TextRange Is Nothing) Then
If Not (placeholder.TextFrame.TextRange.LanguageID Is Nothing) Then
placeholder.TextFrame.TextRange.LanguageID = lng
End If
End If
End If
Next
I still get an out of bounds error on placeholder.TextFrame.TextRange Is Nothing. Did I make a syntax error?
FINAL EDIT: Turns out there was an answer in SO after all. For this specific problem, it was enough to add On Error Resume Next right after theFor Each.
I have had several ideas yet most of the solutions online only restrict certain keys or only numbers, not full strings.
I want a solution that as soon as a keypress of a swear word has been inputted, VB detects it then disallows it. I have been able to do exact string matching so if a user puts the work F*** in, then it shows an error message, but this would not work if the user decided to put in "F***nugget". It would not be elegant nor time feasible to enter every possible combination of swear words. Thanks in advance for help.
If e.KeyChar = "F***" Then
SelectionTextBoxTeamName.Clear()
MessageBox.Show("Please choose something else")
You need a 'string contains' function.
If you're writing in vb.net try String's Contains function, which is used like this:
Dim b As Boolean
b = s1.Contains(s2)
If you're not writing in .net
try InStr function. You can use it as follows:
InStr("find the comma, in the string", ",")
EDIT: after op's comment
If you want to check several swears you can put them in an array and check for each:
Dim swears = {"F***", "S***"}
Dim hasSwears As Boolean = false
For Each swear As String In swears
If InStr(textBox.Text, swear) > 0 Then
hasSwears = true
End If
Next
Now you know if there are any swears according to hasSwears.
If I have a string like input = "AA["
If Right(input, 1) = "[" Then Do stuff
The If statement returns false, even if I try converting things around to chars, etc etc. But if I do this is returns true:
Dim temp As String = Right(input, 1)
If temp = "[" Then Do Stuff
I like knowing little semantics like this, any idea why it comes out this way?
Or don't use Right at all since this is .Net
Dim s As String = "AAAAAAA]"
If s.Substring(s.Length - 1, 1) = "]" Then
Stop
End If
'or
If s(s.Length - 1) = "]" Then
Stop
End If
I've seen weird behavior like that when debugging.
In fact, today I had something simlar
Dim records As Integer
records = If(o.dr Is Nothing, o.ADO.rs.RecordCount, o.ADO.DS.Tables("tbl").Rows.Count)
That should work, using the rs.RecordCount when dr is nothing, otherwise using the Rows.Count. It didn't, records was ending up as zero. Rewrote it as a full if then/else block and it works.
It's never my first thought that the compiler/debugger/ide is messing things up, but you should keep it in the back of your mind for consideration: the programmers that wrote those programs are just as human and fallible as you or me.
It shouldn't. Are you sure you didn't have a typo? The result of RIGHT is a string, and if the input was truly "AA[" the IF will have passed.
I've never had VB act wonky on something like this.
If the code appears in a form, then the .Right property of the form overrides the string manipulation function. You need to specify the parent namespace - e.g. VisualBasic.Right - to ensure that you get the correct method.
I think you may have some kind of strange overload confusion occuring here.
You are specifiing "Right" (which could be calling a local "Right" function).
The function your implying is "Microsoft.VisualBasic.Strings.Right" in most of my code ends up being "Strings.Right" due to the global import.
I would try changing you code to the below and see if it still happens, in order to rule out some overload/scope confusion. (and/or the reduced "Strings.Right")
If Micosoft.VisualBasic.Strings.Right(input, 1) = "[" Then Do stuff
I know, I know, I could have used a for loop, dont tell me anything about that. Please, help!
Private Function LoadSaved() ''//Loads saved clippings if the user wants us to
Dim ZomgSavedClips As StringCollection
If IsDBNull(My.Settings.SavedClips) = False Then ''//If it is null this would return a rather ugly error. Dont want that do we?
ZomgSavedClips = My.Settings.SavedClips ''//ZomgSavedClips name was a joke, I just felt like it.
ZomgSavedClips.Add(" ") ''//This line ought to fix the error, but doesnt
i = 0
While i < ZomgSavedClips.Count ''//This is where the error occurs
ClipListings.Rows.Add(ZomgSavedClips(i))
i = i + 1 ''//First time I wrote this function I forgot this line. Crashed mah comp. Fail.
End While
End If
End Function
The line While i < ZomgSavedClips.Count is bugging, I know that the .count should return null but I even added a blank piece of text just to stop that. Whats up with this? Should I add actual text?
SavedClips is null no? If it is null it could pass the test IsDBNull beacuse the both are not the same
Obviously, My.Settings.SavedClips is still set to Nothing.
SavedClips is regular 'ole null (nothing in VB). Include a check for "My.Settings.SavedClips is nothing". If that evaluates to true then just leave the function.
I even added a blank piece of text just to stop that.
All you did was move where the error happens. You can't call .Add() on a null/Nothing object.
'''<summary>Loads saved clippings if the user wants us to</summary>'
Private Sub LoadSaved() ''//Loads saved clippings if the user wants us to
''//Load saved clips into memory
Dim ZomgSavedClips As StringCollection = My.Settings.SavedClips
If ZomgSavedClips Is Nothing Then ZomgSavedClips = New StringCollection()
''//Apply loaded clips to visible listings
Dim i As Integer
While i < ZomgSavedClips.Count ''
ClipListings.Rows.Add(ZomgSavedClips(i))
i += 1
End While
End Sub
Some notes on this code:
Don't use Function when you mean Sub
Since you'll be selling this code to others, you want to use xml comments at the top so that Visual Studio can give better intellisense helps.
IsDBNull() doesn't do what you think it does.
Yes, you should use a for loop, but since you already commented on that I left the while loop alone with the assumption that there's more code you didn't show us.