Okay say we have a class that implements INotifyPropertyChanged and a property that has code in the setter to raise the PropertyChanged event. On the GUI side we have a text box with the code:
txtFirst.DataBindings.Add("Text", p, "FirstName", True) Where p is a Person object and FirstName is the property that raises the PropertyChanged event.
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I have a public property, "Status" that is an enum. I have a setter method that changes the status and raises the PropertyChanged event. However, the WinForms user interface is not properly updating. I'm pretty sure it's because Status is an enum. Although I was thinking enum was a reference type but I guess it's a value type. Does INotifyPropertyChanged work the same with reference and value types?
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Is there a way to use INotifyPropertyChanged with auto-properties? Maybe an attribute or something other, not obvious to me.
public string Demo{
get;set;
}
For me, auto-properties would be an extremely practicall thing, but almost always, I have to raise the PropertyChanged-event if the property value has been changed and without a mechanism to do this, auto-properties are useless for me.
I have a class, Vehicle. I created two child classes, Car and Plane. I want to monitor the speed, which is a Vehicle Property, and bind it to a control (label, or image, for example) in WPF. When i create a static Class which only purpose is watching the Speed Property, it works, as far as the INotifyPropertyChanged is declared with the Speed Property name.
But the problem is, I have to create dynamicly multiple Cars and Planes by looking in an XML file and deserializing my objects, and creating multiple Car or Plane UserControl (Let's not discuss this way of working, please). So I have to get the Speed property inside the Vehicle Class (which is normal), and I have to get a INotifyPropertyChanged on each Speed of each Vehicle Created. So, my Cars and Planes are loaded, and I have to get all speeds, but I can't create a static Speed property by Vehicle. By the way, by creating a non-static Speed property (as int, for example) in Vehicle Class with INotifyPropertyChanged raised in the setter, it does not work. The event seems to be raised, but my converter is not fired, and my controls does not update.
In my Vehicle Class
Private SpeedValue As Integer
<XmlIgnore()>
Public Property Speed() As Short
Get
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The PlaneView Class is almost the same for this part.
I confirm that the converter is fired just once, the first time, when the tabs are created, because I put a breakpoint on the Convert function definition. After that, the converter is never fired again. So the picture img_fonctionnement is displayed, but it is never updated. But the Speed property is updated, I swear. And the INotifyPropertyChanged (in Speed's setter) is raised, as far as i know with the help of the debugger.
And the "an item with the same key has already been added" (which appears in a messageBox, and not as an exception) seems to appear only when I am to long with the debugger. In normal execution mode, it never shows.
It seems like overkill to set the value of a nullable type and implement iNotifyPropertyChanged. Is there a better way of doing this?
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I'm trying to get my head around excel charts. I've poured over these posts for the last couple of days now and i'm coming up dry. I've got a xl file thats got some data in the first 2 columns. I want to put the data in an XY scatter plot. Column A is the x coordinates and b is the Y.[code]...
View 6 RepliesI have been looping thru all of the rows in a DGV and matching a variable to a specific cell in the row to 'do stuff to that DGVRow.
For Each dgRow As DataGridViewRow In Me.dgvInsertCommercial.Rows
If dgRow.Cells("SomeColumn").Value = pid Then
'do stuff
end if
Is there a way to actually query or make a selection instead of having to loop thru all of the dgvRows?jfc
We have an item cull that retrieves items and their appropriate data from one server. Their Primary Keys need to be INNER JOINed with another table. However, the second table is on another server. We can retrieve that data using a separate select statement and accompanying VB objects.
How would one go about this programmatically in VB? Is a loop the best practice available? Although we are in a Microsoft Ecosystem, Server Linking is not possible.
I need a way to programaticaly block and then later unblock specific websites based on their domain names. I only need to block browsers (so http & https would be sufficient, I guess?) but not just Internet Explorer, it should also work for anyone trying to run Chrome or Firefox too.
View 4 RepliesI am programmatically updating some columns in a datagridview. When the user has also updated some columns then my program generated changes are also saved to the database (MSAccess). If the user does not update a dgv column, my program edits are not saved. I have read in another posting somewhere that I should be updating the bindingsource rather than the dgv cells. I have some code that was attempting to do this but it doesn�t work.
Dim dvr As Data.DataRowView
With TblClassMembersDataGridView
.EndEdit()
.CommitEdit(DataGridViewDataErrorContexts.Commit)
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PS. Is the bindingsource in a on-to-one relationship with the table returned by the Fill method? If not, I can see one obvious error.
I can edit the values in the dgv cells manually, add rows, delete rows all without problem and then update the database.My problem is in one form where I want to allow the user to filter the rows in the grid and then enter a value in a textbox and programmatically update all the cells in one column with that valueI can update the rows, and see the changes in the datagridview. When I try and update the database (using UpdateQuery on the underlying TableAdapter of the datagird) only some of thechanged rows are being updated I though it might be related
View 9 RepliesI'm seeing a strange build bug a lot. Sometimes after typing some code we receive the following build error.
Class 'clsX' must implement 'Event PropertyChanged(sender As Object, e As PropertyChangedEventArgs)' for interface System.ComponentModel.INotifyPropertyChanged'.
And
'PropertyChanged' cannot implement 'PropertyChanged' because there is no matching event on interface 'System.ComponentModel.INotifyPropertyChanged'.
Those error should never go together! Usually we can just ignore the exception and build the solution but often enough this bug stops our build. (this happens a lot using Edit and Continue which is annoying)Removing the PropertyChanged event and retyping the same code! sometimes fixes this.We're using a code generator that causes this error to surface but just editing some files manually triggers this exception too. This error occur's on multiple machines using various setups.
I am using .net 3.5 and vb.net 2008 I have a program that copies access databases (.mdb) over from one server to another to be used ofr a ArcGIS webservice. The databases are edited on one server then nightly copied over to the webserver so they can be consumed in an intranet page).
The program is just a windows form that runs copy command in the load procedure. The program itself is run form the scheduler as an admin user for the machine but no one is actually logged in when it runs at 1 at night. I then get this kind of error reported to me:
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Thought I'd see if Stack overflow is quicker than me testing something while I get a thousand interruptions from other work :)
I'm updating an old VB net application and trying to refactor some of the logic as I go. The app looks for data from a single date across a few tables and writes that view to a file.
Writing the query in SQL I'd get the equivalent of
SELECT * FROM table
WHERE CAST(FLOOR(CAST(table.date AS float))AS datetime) = '15-Jul-2010'
Ideally I'd use
SELECT * FROM table WHERE date=@input
and add a date object as a parameter to a System.Data.SqlClient.SqlCommand instance
Are those two comparable? Will I get the results I expect?
I wanted to know if anyone could tell me how to access the Click_event.I have a boarderles form with a panel control which has the Dock property set to fill and on the panel I have placed a Label also with the Dock property set to fill. I also have a timer running.How can I get code to execute in the Label1 click event.I've tried doing it by using the generic Click_event and also with two variations of the Click_event Handles parameters
'Alternativ 1:
Private Sub Form1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Label1.Click
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There is newer code in a follow up post. I suggest using the code in the later post rather than the code in this one. You can still read this post though. When designing a user interface, one should be conscious of how many individual controls are required to implement the functionality. In some cases an initial design may begin with many buttons or textboxes (for example) but then further review of
the actual required functionality allows for a reduction in the number of unique controls.
But other times, there isn't a better way (which will still make sense to the user of the application) then to have a series of many repeated controls. So in the cases where one can be certain that the best UI implementation for an application will require the use of multiple copies of a given control, then it often becomes necessary to maintain some method of managing all of those controls at various points
throughout the application. Doing so typically requires that one build up some collection of controls which can then be accessed by index in order to work with any given control; but this can lead to a lot of clutter in the code file which handles these control's events. For instance there will be some kind of collection declaration, some recursive routine to find all of the controls of interest, and then any number of event handler methods with long lists of Handles clauses, or additional code loops to wire up the event handling for each control.
Purpose Since most of this functionality could be considered a requirement regardless of the type of control being managed, or its required functionality, it may make sense to wrap all of the control management functionality into a single class. And since our first requirement is a collection of controls, then a base collection class could be the perfect starting point for our control manager. There are a number of existing thread around this topic, with some recent (at the time of this writing) ones being:[URL]..In this, and related, threads I have posted examples of a simple TextBoxManager and ButtonManager control. But again, with so much similar functionality required regardless of the control being managed, it would be technically possible to create a generic ControlManager(Of T As Control) class which can manage any type of control.
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So in summary, one can facilitate managing a large number of user interface controls by building a "control manager" class which both encapsulates the list of control instances, and deals with adding and removing defined event handlers for every control it manages. The generic control manager class itself can be inherited and extended into a more specific class on a per-application basis in order to provide more application-specific functionality. Reed Kimble - "When you do things right, people won't be sure you've done anything at all"
If I have the following ListView, how can I attach a SelectedIndexChanged event listener to the DropDownList so I can perform a command on the respective object? Imagine I have a list of new users and I want to add them to a usergroup by selecting the group from the DropDownList.
<asp:ListView ID="NewUsers" runat="server" DataSourceID="NewUsersSDS" DataKeyNames="ID">
<LayoutTemplate>
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I have a maximized form that has controls at the top of it and a large DataGridView that is docked below all the controls. Its kind of like the Ribbon in MS Office. The controls cover about 1/4 of the screen at the top. I would like a way for the user to click a button to hide all the controls then automatically expand into the place the controls were so the user can view more data in the DataGridView and visa versa. For example, in MS Office Excel you can hide the ribbon by clicking a tiny button that has "^" on it.
I'm not very familiar with all the controls in Visual Studio so I would like to hear some recommendations. Is this situation ideal for a SplitContainer or ToolStripContainer or am I way off base here?
I've got a couple of these NumericUpDown controls I put on a form. Without describing too much about the form I basically want to update some variables each time one of these NumUD controls changes value. So for each NumUD I have a call to a Recalculate subroutine within their "changedValue" event.
There are actually two problems. First, if I initialize the "Value" property to something other than zero in VB2010 at DESIGN TIME it won't even open the form when I hit RUN. It gives me a "No Source Available. No symbols loaded for any call stack frame" error. The error box says "InvalidOperationException" was not handled. So if I try to set the initial value of the Value property to anything but zero of either I get this error.
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I've been building controls for many years professionally and personally, but even back in VB6 days I just could not work this out. After all this time I remembered about it again.If I create a usercontrol/containercontrol and add one or more controls to the controls surface, I just cannot figure out how to access the controls at design time.
View 4 RepliesI want to draw a rectangle over some controls so that the controls are partly obscured.
View 2 RepliesI have a query about dynamically added controls to a form. I have a series of buttons which are created and added at run time. I have a two drop down lists and two buttons which are created at design time. Button 1 creates a series of buttons called "Test 1.x" based upon the selection of the two drop down lists. This works fine and am happy with the logic.However.... Button two should remove all the dynamically created buttons from the form.This does not happen. What does happen is that 50% of the buttons are removed starting with the first one. WHen checking the loop it only enters the loop half the amount of times that there are buttons. Very strange. When the loop is run repeatability it will remove all controls. Why will my logic not remove all the dynamically created controls at once? What is wrong with my logic?
I attach two code snippets and the .net file for your consideration.Button method which creates the dynamically created buttons from the two drop down lists and adds to form
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Dim Count As Integer
Dim MaxHours As Integer
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i have created control array , now i wann to loop around as well wann to find which control has triggered the respective event my code :
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The object browser in visual studio contains many controls and properties ....so is it possible to remember in mind all these controls. Whenever i am programming in vb 2008 and for reference i look at the examples on internet i always find some new controls,properties etc which makes me confuse.So i was wondering If by any means there is a way to remember all these controls
View 4 RepliesI have aspx form with several textboxes.They are populated with values from a table via retrieval of a dataview.If the row count for the dataview is 0, then I'd like to reset the values in all textboxes. How can I loop through all the textboxes and set a default value?I've tried the following, but no sucess.
For Each ctrl As Control In Page.Form.Controls
If TypeOf ctrl Is WebControls.TextBox Then
CType(ctrl, WebControls.TextBox).Text = ""
End If
Next
My first For Loop was using Page.Controls but it returned only 1 count.The textboxes are inside a tabpanel (ajax), so do I have to locate the tabpage and then find all it's controls (for each tabpage)?
How can I add controls to a form in code and set the properties of the controls using the With statement?Also I would like to know how to add a container control and then add a control to that container.
View 2 RepliesI have a slight problem With an enumaration of child controls on a form. The following code will not get but about have the controls that are on the form. The controls show that the count is correct but when it goes through the loop it skips over some of the controls. If you run it through the enumeration two or three times it will get all the controls a few at a time. The solution uses two forms, one that has the controls and the other that labels are made and displayed on. The Tx is just a index to add a number to the label.name and rename the label. So each label is identified seperately. This works for all the the controls that are seen in the for each loop.
View 11 RepliesI created a class that can take either usercontrol.controls or form.controls as a parameter,how can i pass either to that class? as a property or how?
View 4 RepliesI am rather irritated at this. I have no clue why looping through controls on a form and in groupboxes leaves out 75% of the controls.
Here's the code I have:
Dim settings As String = ""
Dim gbControl As Control
Dim gbbox As Control
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I want to have setting save all settings to an ini file, and not have to reprogram the saving routine when I add a group box or control. At random times, any number of controls can be disabled, checkboxes can be checked and unchecked, radiobuttons can be checked and unchecked. Regardless of the state of the control, I want the control to show up in the loop. But they don't. Only controls that are enabled and only checkboxes that are checked, every other control state is ignored. That's crap, and is definitely not what is needed by any programmer of any type. We're capable of determining if a control is enabled, hidden, checked, visible, and otherwise.
How do I get the controls to be included in the loop regardless of their state?
I cannot work out the correct formatting of the above type addressing for a textbox in a (sort of) array of textboxes such as
textbox_1
textbox_2
textbox_3
etc.
The controls are on Tabs but I don't think I need to include the Tab as a container control, just refer directly to the textbox on the form, but I cannot work out how this is done in VB .NET format. In VB6 it was relatively straightforward but VB .NEt seems it is different. Can anyone help me with the correct way to formulate
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