finding a solution for find string in listbox - vb.net

I has 4 item on my form.........
tow listbox ,one button and one text box
I has a listbox 'A' with many items.....
i need a item in a listbox 'B' from listbox 'A'
steps are as follow.....that i like to performe...........
1)enter a word or character in a textbox
2)press a button
3)the list appear in listbox 'B'.......that is character or string start in listbox 'A' that is we write in textbox (for matching)
i need a help in which a item that can be in listbox 'B' is getting for listbox 'A'
that is Starting string or character we enter in the text box.
please try to solve me out..........

Not quite sure I follow. Using the text box' Changed event would be a good trigger instead of a button. Just iterate the list items and check for a match with String.StartsWith. For example:
Private Sub TextBox1_TextChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles TextBox1.TextChanged
ListBox2.Items.Clear()
If TextBox1.Text.Length > 0 Then
For index As Integer = 0 To ListBox1.Items.Count - 1
Dim txt = ListBox1.Items(index).ToString()
If txt.StartsWith(TextBox1.Text, StringComparison.CurrentCultureIgnoreCase) Then
ListBox2.Items.Add(txt)
End If
Next
End If
End Sub

I don't have an IDE in front of me, and it's been a while since I've done WinForms development, so I may not have the exact event name or other stuff, but you get the idea. This also means my code will be in C# since I'm more familiar with that, but you should be able to find the VB equivalent.
You'll want to bind to the proper event on the text box first. Maybe the KeyPress or KeyUp event? Or TextChanged? You want one that fires any time text changes in the text box. In that event, you'll loop through the items in listbox A and compare their values to the text in the text box. Basic string comparison is all that's needed, if there's a .StartsWith() or something of that nature, otherwise some basic use of .Substring() will do fine (based on the length of the string in the text box).
The loop would likely be something along the lines of:
listboxA.Items.ForEach(i =>
{if (i.StartsWith(textboxA.Text)) listboxB.Items.Add(i);});
Or...
foreach (var i in listboxA.Items)
if (i.StartsWith(textBoxA.Text))
listboxB.Items.Add(i);
Like I said, this is all off the top of my head, so the code may not be exact. But hopefully you get the idea.

Related

Textbox: missing first character typed on the TextBox

I have 2 text boxes to accept info but only one of them is need at the same time (One is for selection of the first letter and the other is for selection of any part of the name)
So I need to delete the text of the other textbox when the user start typing on the textbox
Something like this work:
Private Sub TextBox2_TextChanged(sender As Object, e As EventArgs) Handles TextBox2.TextChanged
TextBox1.Text = ""
End Sub
But there's a problem, the first character the user type is not displayed, I think is because the first character typed is used to launch the event.
Example:
TextBox1.Text = "A"
when the user click on TextBox2 and type michael the "m" is lost
I don´t want to use the "GotFocus" event because a simple TAB pulsed to jump from TextBox1 to another control can delete the text on TextBox1 when the user stop on TextBox2, even if he don´t want to type anything there
How can I manage this mistake?
Right answer:
From #Plutonix
"No user is going to expect this behavior and you will go mad trying to divine when to execute and when not to. A better thing might be to select the text on the Enter event - at least that has been seen before by users"

Filter a listview in vb.net

Currently I have a program that is able to write to a ListView with column named : number, time, description . This listview is not bound to anything data, I'm just basically writing into it using the code.
What I want to do is to have a TextBox, whereby if the user wants to look at particular number i.e. 2, when they type into the textbox, then I want the listview to only show data with number = 2. When there's nothing in the textbox, I want the listview to show all the data.
I have being looking around on the internet and I didn't seem to find a filter method. Does it even exist and if so how would I go about implementing this.
All help is appreciated.
While I recommend using a DataGridView with DataSource but in cases that you need to use ListView, you can use this solution.
You can filter your list view this way:
Define a member field as backup storage of items:
In form Load after adding items to list view, store each item in that member field
Put a TextBox and a Button on form and handle Click event of the Button and in the handler, first clear all items of ListView then each item from that backup storage that matches with criteria.
Member Field for Backup of Items
Private ItemsBackup As New List(Of ListViewItem)
Fill backup after loading items in ListView in the form Load event
For Each item As ListViewItem In ListView1.Items
ItemsBackup.Add(item)
Next
Code of Filter
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Me.ListView1.BeginUpdate()
Me.ListView1.Items.Clear()
For Each item As ListViewItem In ItemsBackup
If (item.Text = Me.TextBox1.Text Or String.IsNullOrEmpty(Me.TextBox1.Text)) Then
Me.ListView1.Items.Add(item)
End If
Next
Me.ListView1.EndUpdate()
End Sub
You can also use above code for TextChanged event of the TextBox.
Here is a test data:
For i = 1 To 30
Dim item As New ListViewItem(i.ToString())
item.SubItems.Add(DateTime.Now.AddHours(i))
Me.ListView1.Items.Add(item)
Next
A normal .NET ListView can't do this without a considerable amount of work. So, you could use ObjectListView -- an open source wrapper around a standard .NET ListView -- which has already done all the work for you.
It has built-in filtering (and highlighting)

Populating a textbox, if another textbox is populated

i've got two textboxes in my form.
According to title, when I write something in one textbox (a random one), i need that at the same time, in the other textbox a text (given in the code) appears.
1 letter for 1 letter
1)Example with random text:
1 textbox ) How are you?
2 textbox) Let's just c
2)Example with random text:
1 textbox ) What is the aim of the project?
2 textbox) Let's just chill out for a mome
thanks so much
You will need to determine which responses you would like to which questions. However, the tackle to letter for letter problem. I would use the substring method and get the length of the current text.
Dim Response as String = "Hello World!"
Private Sub Text(ByVal..) Handles Textbox1.changed
Textbox2.text = Response.Substring(0, Textbox1.text.length)
End Sub
As the text changes in the textbox you are typing in, this will output the response corresponding to the length of the text input. Since the event is textbox.changed, each character entered will update the second textbox
You need to use an event based code here. I would use a loop per stroke of the key and make the event "Key Press." Write the code onto the textbox you are inserting data into.

winforms vb 2008 textbox validation issue

I have vb 2008 Winforms application.
In my Branch form I have 11 textbox fields and I want to validate 8 of them, either mandatory, or required format such as UK postcode, UK tel nos etc.
My issue now is that when the validation starts, it is validating the last text field first ( or seems to be)
here is my code
For Each oCtrl As Control In Me.Controls
If TypeOf oCtrl Is TextBox Then
oCtrl.Focus()
If Validate() = False Then
Exit Sub
End If
End If
Next
what's wrong please?
what's wrong please?
The controls collection isn't sorted or grouped. Your loop will access them in whatever order the collection has them.
Without more code it's hard to say how to fix it. However a tip may be in order. Use the same handler to handle the validate event for each textbox. This way you can keep the user at that textbox until the input is valid.
is it possible to add the items to the collection in the order of their tab indexes on form Shown event, how would I do that please?
A List(Of TextBox) and a custom sorter would probably be the way to go
Dim AllTB As New List(Of TextBox)
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles Me.Load
AllTB.AddRange(Me.Controls.OfType(Of TextBox))
AllTB.Sort(Function(x, y) x.TabIndex.CompareTo(y.TabIndex))
End Sub
To loop through the textboxes use:
For Each tb As TextBox in AllTB
Because the TextBoxes are in the list by reference you can get or set any of the properties in the textboxes and any changes, will be reflected on your form. You could also use sequential names for the textboxes, tag property, etc. and sort by that.

(VB.net) Find specified text on an entire line (not just beginning characters) in a listbox

I have a listbox where each line contains a short 3-4 character model number followed by a tab and then the product name the model number corresponds to. I also have a textbox which I am using to search the listbox.
The code I am using so far works somewhat, just not exactly how I would like. If I enter search text it will highlight the results in the listbox but only for the first characters, is there anyway to search the text of an entire line (index) of a listbox?
Right now I am using the following:
Private Sub txtSearch_TextChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles txtSearch.TextChanged
ListBox.SelectedIndex = ListBox.FindString(txtSearch.Text)
End Sub
On the assumption that your line representation is the ToString() of the item in the list:
ListBox.SelectedItem.ToString().Contains(txtSearch.Text)
I got it to work by looping through and using contains. Issues with upper and lower case were giving me incorrect results so I converted the criteria to all lower.
For i = 0 To ListBox.Items.Count - 1
If ListBox.Items(i).ToString.ToLower.Contains(Trim(LCase(txtSearch.Text))) Then
ListBox.SelectedIndex = i
Exit For
End If
Next