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 6 RepliesIn 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 RepliesI 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 RepliesIt looks like there is a bug in the DateTimePicker control, because I don't find any event specific for the changing the check state of the checkbox, only the ValueChanged event seems available. So that event should trigger every time the date in a dtp is changed manualy, or by choosing a date from the calender or when the checkbox in the dtp is checked or unchecked by clicking on it, the event ValueChanged should be triggered. But it doesn't do that all the time.
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I am using VB Stuido 2008, Net Framework 3.5.I have one Checkbox to Identify the record as Inactive if checked. When I load the form the checkbox is alway unchecked, which is what i want. However, when I go to add a new record the checkbox, not the text for the checkbox is always shaded green, not a checkmark. The checkbox then reacts as if it is checked. This makes it necessary to uncheck the checkbox or else all my record react as if checked.
in the table defintions I have set the default binding value to ((o)) which = unchecked. Iafter setting the default value to ((0)) I deleted the checkbox from my form and then replaced. Not I still get the checkbox shaded which reacts as if Checked.
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]....
Are there any way to trap key when the DateTimePicker is dropdowned?
I have tryed many ways but no effect.
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.
So 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 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've been having a problem setting certain items in a listbox as checked when the form is loaded. I have tried putting the code in the form_activate, form_load, and form_shown events and each still crashes when it encounters:
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I'm needing to determine if the calendar dropdown is currently being shown in a WinForms DateTimePicker. I've got a custom control that inherits from DateTimePicker, and I'm handling the KeyDown event in order to do stuff with navigation keys, but I'd like to bypass that code if the calendar dropdown is open, so that the user can use their navigation keys there.
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When DateTimePicker check state changed,ValueChanged and TextChanged events don't work always.
View 8 RepliesI have the problem in VBA for Access, but I assume that it is related to Visual Basic as a whole as well.
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I have the problem in VBA for Access, but I assume that it is related to Visual Basic as a whole as well.I have the following code:
public sub NavigateIE
dim ieobj as shdocvw.internetexplorer
ieob.navigate ("Some URL")
end sub
[code]....
How can I link the DocumentComplete event of ieobj to the subroutine named customeventforieobj?
Let's say I have a checkbox1 control on form1. I then open form2. I want to be able to change the checked state of checkbox1 on form1 from form2.[code]...
View 5 RepliesOn the form that i have there is a listview with checkboxes enabled it all works fine but when i close and reopen the form all the previous checked checkboxes are uncheched . Is there a way to save the state of the checkboxes and on form load to restore them ?
View 5 RepliesI have a menu bar like this.I need to use them like radio buttons. So i have come up with this. Seems a nasty hack since it loops all my menu items. And if i later add different checks it would interfear.
vb
Private Sub mnuMainMenuToolBarComposeExistingThread_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) _ Handles mnuMainMenuToolBarPrivateMessage.Click,
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I am using VS 2008. I have a listview control whitch 'checkboxes' property enabled.My question is: how can I trap a MouseMove event over an item only, excluding the associated checkbox?I have the following code in MouseMove event of the ListView control but it cannot differentiate between an 'item' and a 'checkbox:
Private Sub mylstview_MouseMove(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles mylstview.MouseMove
Dim oListViewItem As ListViewItem[code]....
How can I set up an application wide event trap that is triggered when my database connection status changes?i.e. no matter what form the user may be on if the connection is terminated for whatever reason a message box is displayed to the client requesting whether the program should try and reconnect with the database or not.
View 9 RepliesI'm trying to force an always maximize setting
View 1 Repliesim making dynamic sql statement rmode is a radio button and tmode is a combo box
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I'm trying to program a personal project, but I've hit a bit of a bump in the road.I've got a Button, a Textbox, and a CheckedListBox; when the button is pressed, whatever is in the TextBox is added to the CheckedListBox. However, when the form is closed and reopened, all of the CheckedListBox's items are no longer present. My CheckedListBox's name in the code is ZapList.
Can someone assist me in, not only saving all of the CheckedListBox's items, but retaining whether or not they were checked as well as the order they were in? I've run out of hair to pull (figuratively) and I really don't want to quit this project, too much effort has gone into it and I'd hate to see it go unfinished like my numerous other projects. :icon_cry:
I am trying to access the checked state of a CheckBox from a BackGroundWorker thread. I am utilizing properties and it seemed to work just fine. However, I'm using 10-15 CheckBoxes and I think using the InvokeRequired property would probably be best. I've looked over JMC's thread that talks about how to access controls from the worker thread a bunch of different times and I can't seem to grasp the concepts. When it comes to the InvokeRequired property, I suppose I understand why it is needed. But I'm not sure if I understand it completely.
From the example that JMC provides:
vb.net
Private Sub ResetTextBoxText()
If Me.TextBox1.InvokeRequired Then
Me.TextBox1.Invoke(New MethodInvoker(AddressOf ResetTextBoxText))
Else
Me.TextBox1.ResetText()
End If
End Sub
If I'm not mistaken, this tells us that if invocation is required to access the control, then we access via the MethodInvoker if not, then we just access to directly? So, if I need to check the checked state of a check box, I know I can just put a conditional statement after the Else line if I can access it directly. But, if I can't how would I use MethodInvoker to check the checked state? And then, when calling it from the worker thread, would I just call the sub?
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 RepliesI have managed to get it to write a string to a textfile if the listviews checkbox is checked but i can not get it to write a particular string if it is unchecked.
'LOOP CHECKED ITEMS
For Each lstItem As ListViewItem In Me.ListView1.CheckedItems
Next
How do i Iterate an unchecked item as the library doesn't have .UnCheckItems?
If its checked i need to add "true" to the string and if its unchecked i need to add "false" to a string that gets written to a textfile.
I want to use property bindings under application settings to store settings for my program. However I have run into a problem. For some reason the checked property is not binding to drop down menu item's checked state. The binding works for text boxes and other controls. I have tried to bind both using the checked property, and checked state property. Auto check on click for the menu items are set to true.
Anyone have any recommendations in getting the app-settings property binding to work without the need to manually set that info and manually run My.Settings.Save?
Is there Any way to handle the crtl + Alt + Del Key combination. Take for instance in a quiz application (Win Forms ), the user should not be able to switch to other windows till the test is over.
I'm able to capture the ctrl and alt key strokes individually, using c# standard properties. but once they user hits the del key . The control goes out of my appliation and windows handles it.