The check box list has an event called "ItemChecked" or something, which triggers when an item is about to change its checked status.
So, it is before the check occurs.I couldn't find an event that occurs after the item has changed.. I want to execute some code only when an item is checked or unchecked.
I have a checkbox list which is filled with entries from my database on page load. I need to update an entry in my database when a item is checked and when an item is unchecked. Right now I am doing the following:
<asp:CheckBoxList id="check1" AutoPostBack="True" TextAlign="Right" OnSelectedIndexChanged="Check" runat="server">
</asp:CheckBoxList>
And the function:
Sub Check(ByVal sender As Object, ByVal e As EventArgs)
Dim sql As String
If check1.SelectedItem.Selected = True Then[code]....
The error is: "Object reference not set to an instance of an object." Is there a better way to check if a list item is checked or unchecked?
I have this code:
Code:
Private Sub CheckBox1_CheckedChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles CheckBox1.CheckedChanged
If CheckState.Checked Then
AmxModXInstallDir.Enabled = False
Button1.Enabled = False
[code]....
When i check the box, it enables all controls, if i uncheck it, nothing happens.
I want to create a solid checkbox that is checked by default, and is not clickable. If you click it, nothing will happen . how to do this?
View 2 Repliesfrom the code below I am trying to find out if checkBox1 is Checked or Unchecked. and then I want my settings to remember if it is checked or unchecked. so when the form is loaded I want my settings to load the last action.... ie checked or unchecked.
so if a user check's the checkbox1 then the message will not show, But if it is unchecked the the messageBox will be shown
Private Sub CheckBox1_CheckedChanged(sender As System.Object, e As System.EventArgs) Handles CheckBox1.CheckedChanged
If CheckBox1.Checked = True Then
[Code]....
In Vb.net 2005 how can i trap the checked/unchecked state of a datetimepicker through an event. I'm trying to execute two different methods based on the checked/unchecked state of a datetimepicker when the user clicks the datetimepicker. When the user checks the dtPicker Method A is executed, when the user unchecks it Method B is executed. How can i trap it.
View 1 RepliesSo I'm trying to figure out how to correctly override GetHashCode() in VB for a large number of custom objects. A bit of searching leads me to this wonderful answer.Except there's one problem: VB lacks both the checked and unchecked keyword in .NET 4.0. As far as I can tell, anyways. So using Jon Skeet's implementation, I tried creating such an override on a rather simple class that has three main members: Name As String, Value As Int32, and [Type] As System.Type. Thus I come up with:
Public Overrides Function GetHashCode() As Int32
Dim hash As Int32 = 17
[code]....
Problem: Int32 is too small for even a simple object such as this. The particular instance I tested has "Name" as a simple 5-character string, and that hash alone was close enough to Int32's upper limit, that when it tried to calc the second field of the hash (Value), it overflowed. Because I can't find a VB equivalent for granular checked/unchecked support, I can't work around this.
I also do not want to remove Integer overflow checks across the entire project. This thing is maybe....40% complete (I made that up, TBH), and I have a lot more code to write, so I need these overflow checks in place for quite some time.
What would be the "safe" version of Jon's GetHashCode version for VB and Int32? Or, does .NET 4.0 have checked/unchecked in it somewhere that I'm not finding very easily on MSDN?
EDIT:Per the linked SO question, one of the unloved answers at the very bottom provided a quasi-solution. I say quasi because it feels like it's....cheating. Beggars can't be choosers, though, right?
Translated from from C# into a more readable VB and aligned to the object described above (Name, Value, Type), we get:
Public Overrides Function GetHashCode() As Int32
Return New With { _
Key .A = _Name, _
[code]....
This triggers the compiler apparently to "cheat" by generating an anonymous type, which it then compiles outside of the project namespace, presumably with integer overflow checks disabled, and allows the math to take place and simply wrap around when it overflows. It also seems to involve box opcodes, which I know to be performance hits. No unboxing, though.
But this raises an interesting question. Countless times, I've seen it stated here and elsewhere that both VB and C# generate the same IL code. This is clearly not the case 100% of the time...Like the use of C#'s unchecked keyword simply causes a different opcode to get emitted. So why do I continue to see the assumption that both produce the exact same IL keep getting repeated? </rhetorical-question>
Anyways, I'd rather find a solution that can be implemented within each object module. Having to create Anonymous Types for every single one of my objects is going to look messy from an ILDASM perspective. I'm not kidding when I say I have a lot of classes implemented in my project.My final implementation, which fits the constraints of GetHashCode, while still being fast and unique enough for VB is below, derived from the "Rotating Hash" example on this page:
'// The only sane way to do hashing in VB.NET because it lacks the
'// checked/unchecked keywords that C# has.
Public Const HASH_PRIME1 As Int32 = 4
[code]....
I also think the "Shift-Add-XOR" hash may also apply, but I haven't tested it.
I have a Main form, called Main.vb, that is a Parent Form. I have another form called Notes.vb. Inside Main.vb I have a toolstrip with a button on it called Notes. I'm wanting to change the checked status of the Button to either True when the Notes.vb window is open inside the parent or to false when it is close. Is this possible?
View 6 RepliesHow can i trap the checked/unchecked state of a datetimepicker through an event. I'm trying to execute two different methods based on the checked/unchecked state of a datetimepicker when the user clicks the datetimepicker. When the user checks the dtPicker Method A is executed, when the user unchecks it Method B is executed. How can i trap it.
View 6 RepliesIn a listview with check boxes, there are two fields being loaded, ID and Lastname. With this information I want to get the ID of the person whose box is checked with this sub:
[Code]....
How to count the total no. of asp.net checkboxes, checkboxes checked, no. of checkboxes remain unchecked in webform using vb.net ?I m using Visual studio 2008 with vb as a language ..I my webform i have 10 checkboxes...i wanna count total no. of checkboxes in webform in textboxes1 total no. of checkboxes checked in webform in textbox2 total no. of checkboxes remain unchecked in webform in textbox3?
View 2 Repliesremoving Listbox item from checked Listview item.The code I tried just errors out.
Private Sub ListView1_ItemCheck(sender As Object, e As System.Windows.Forms.ItemCheckEventArgs) Handles ListView1.ItemCheck
If (e.CurrentValue = CheckState.Unchecked) Then
ListBox1.Items.Add(Me.ListView1.Items(e.Index).Text)
ElseIf (e.CurrentValue = CheckState.Checked) Then
[Code]...
Regarding my college project. i'm working on a sales system . i have a form which consist of all the following information( item code , item name , item price , quantity of item ) which is display using a data grid . data input by user using text box and all this information will be stored in a database(sales database) i'm using ms access 2007. the grand total will be displayed in a text box . and amount paid will be input in a text box too , my major problem now is how to i create a reciept that will have all this information of the purcase. i have a reciept button . what the next step ? i dont have any idea how to get the reciept done.
Imports System.Data.OleDb
Public Class Form5
Dim con As New OleDbConnection
[CODE].......................
I have some code to execute code at runtime...
Here is the main
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Try
If TextBox1.Text.Trim <> "" Then
If TextBox2.Text.Trim <> "" Then
[code]....
When the button is pressed, it all works and the following files are created: yahoo.dll and yahoo.pdb My question is this: What is the code to load the already compiled yahoo files to execute the code again, without having to recompile the code?
This is probably easy as well. But I have this listview which contains exe files I've listed up. Now, I want to execute these exe files in turn from which items are checked or not. So, I've tried this:
For each item in listView1.CheckedItems
Msgbox item.ToString
Next
Cause I noticed that the item in checkedItems doesn't contain much. And if I convert it to a string, it ends up in the msgbox looking like this: ListViewItem: {Filename.exe}
I have a list of options on my site that a user can select. What I want to do is provide functionality to limit the amount of content the user gets based on his selection in a CheckBoxList. Once he's selected what he wants, he'll click Save and his selection will be written to the database. The CheckBoxList is initially populated from the Modules table. This provides a list of modules that the user can select. When he clicks Save, the code needs to loop through this CheckBoxList and "pick out" the values for the CheckBoxes that were checked, disregarding the ones that weren't. The problem is that whether a CheckBox is checked or not, the debugger returns a False value for the CheckBoxList.Items(i).Selected property.
Here's my code:
Private Sub AddUpdateOrg(ByVal OrganizationName As String,
ByVal Action As String, Optional
ByVal Target As Integer = Nothing)
[Code] .....
Its possible that this behavior is the result of a postback from the save button. Upon further examination of the code, I've reconsidered the possibility that this issue is caused by a postback as the CheckBoxList is not bound on page load.
Given a CheckedListBox instance, how can I accomplish that a maximum of one item can remained checked?
View 3 RepliesGiven a CheckedListBox instance, how can I accomplish that a maximum of one item can remained checked?
View 1 RepliesI have a chechlistbox and i have 10 items. and items are checks randomly.
i want to determine which items in checklistbox is check.
I use the code below to get the checked item value in my ilstview, i also need the subitem values (there are 2) i can't seem to figure out how.
[Code]....
I have a form with a ContextMenuStrip Added and a Listview. I set the 'ContextMenuStrip' property on the listview to my newly created ContextMenu.
So, I am creating the Menu items from a database (no problems here). But I cant seem the get certain menu items to a checked status when creating the menu item from the database.
The Code below is a sample of what I am using.
Public Sub LoadMenu(_Menu As ContextMenuStrip)
Dim n As Long = 0
Try
[code]....
Does anyone know of a control such as a Checked List Box where each item can have a value against it.For example you have a list of fruits and in the listbox it displays Apple, Orange & Banana but the values for those items are A, O & B.
View 3 RepliesWith my CheckedListBox, I am trying to get the text of each item that is checked and add it to a listbox, but it does not get everything currently checked. If I have 3 items checked, it only adds 2 items. If I deselect an item, it appears.
lstOpCodes.Items.Clear()
Dim OpCodeCollection As CheckedListBox.CheckedItemCollection
OpCodeCollection = chkOpCodes.CheckedItems
For Each opcode In OpCodeCollection
lstOpCodes.Items.Add(opcode)
Next opcode
I want to adding checked item from checkedlistbox to my combobox, but i have a little problem here.Combobox only show 1 item last checked.This is my sample code.
If CheckedListBox1.CheckedItems.Count <> 0 Then
For i As Integer = 0 To CheckedListBox1.CheckedItems.Count - 1
cbCheckedItem.Text = CheckedListBox1.CheckedItems(i).ToString
Next i
End If
I remember doing this in a checkboxlist element, but with listview element its giving a hard time.
Private Sub CheckedListBox1_ItemCheck(ByVal sender As Object, _
ByVal e As ItemCheckEventArgs) Handles ListView1.ItemCheck
If e.NewValue = CheckState.Checked Then
For index = 0 To Me.ListView1.Items.Count - 1
[Code]...
I have a list of items in a ListView and at the top of the list there is an item that is supposed to select all the items in the ListView. I can get it to select all of the items when it's checked but then I can't deselect any other items. I need the to know which item was checked, when putting the sender into a message box I get "System.Windows.Forms.ListView, Items.Count: 1, Items[0]: ListViewItem: {All}". How do I get the sender's item?
View 6 Replies1) Can I set a CheckedListBox item to be disabled programatically so that it cant be checked?
2) Why doesn't the SelectedIndexChanged event fire when I check or uncheck an item programatically? But it does if I do it manually...
[code] The problem is that AffiliazioneID = chkFonti.CheckedItems(i).ValueMember it's wrong.How can I correctly obtain the valuemember of every checked item?
View 4 RepliesOk. So, how do i save things. Ive made a Checked Item Box. But i can't get any of the things to Save that i have Checked?
View 9 RepliesCan I make a menu item to execute 3 tasks? For instance when I select a file from a ListBox and I press ToolStripMenuItem1, the program will move the selected file to a directory, execute archive.bat file and the move the archived file to another directory? I tried but I can make only one operation - to move the file.
View 6 Replies