Databinding Manual Writevalue In .net Winforms?
Oct 28, 2009
If I turn off automatic updating of a binding data source by setting DataSourceUpdateMode = Never and then use a button to update the whole lot (using binding.WriteValue), a problem occurs - Namely, only the first bound control's data source is updated. All other controls are reset back to the original values.This is because when the current object changes (as happens after the above WriteValue), if ControlUpdateMode = OnPropertyChange, then all the other controls re-read in the value from the data source.
One way is to derive a class from BindingSource and add a WriteAllValues method.This method does the following:
(1) For each Binding, save the ControlUpdateMode
(2) For each Binding, set ControlUpdateMode = Never
(3) For each Binding, call the WriteValue Method
(4) For each Binding, reset ControlUpdateMode to the saved value
(5) For each Binding, if ControlUpdateMode = OnPropertyChange, call the ReadValue method.
If working with your own classes, would implementing IEditableObject resolve the issue?In another control I'm working on, I implement my own binding. The way I get around the issue in that is with the following code. (I've put in the bare minimum, I hope you can follow it!):
Private Shared ControlDoingExplicitUpdate As MyCustomControl = Nothing
Private Sub UpdateDataSourceFromControl(ByVal item As Object, ByVal propertyName As String, ByVal value As Object)
Dim p As PropertyDescriptor = Me.props(propertyName)
[code]....
So, when UpdateDataSourceFromControl is called, all the CurrentItemChanged events will be called for all other controls in the same BindingSource. However, because ControlDoingExplicitUpdate is set, they will not re-read in the value from the data source unless they happen to be the control that did the updating.ControlDoingExplicitUpdate is set to Nothing after all these events have completed, so that normal service resumes.
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Dec 18, 2009
How to bind data from database to combobox of winform in VB.NET .
Database : MSSQL server managemant studio
Front End : Vb.net 2008
In the combo box binding,i need to put "Product_gid" in index and "Product_Name" in the value of combo box.How do i add an item "Select" in the 0'th position of Combo box,So that every time i opened the list of combo box,the 1st item will be "Select",other from database.
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Jan 5, 2012
I have the following structure
|-Table 1
|--PK IDT1
|--Name field
|-Table 2
|--PK ID
|--FK IDT1
|--Name field
I want to bind Table 1 to combobox1 and Table 2 to combobox2 so as when someone selects a value in combobox1, combobox2 populates with only the rows with the FK IDT1 value from combobox1. Is this possible with databinding or do I have to code it?
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Jun 22, 2009
I'm trying to bind CheckedListbox's Cheched items to Combobox my code is given below
Private Sub chklColumns_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles chklColumns.SelectedIndexChanged
cmbSort.DataSource = chklColumns.CheckedItems
End Sub
whenever I check an item first time it loads one item to the Combobox, but when I select second item still I have single item in the Combo...
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Jun 15, 2012
Short and simple question. In Winforms you can bind a dataview to a combobox or some other control by simply:
combobox.DataSource = dataview
combobox.DisplayMember = "Something"
In WPF I've generally done databinding using an ObservableCollection and edits to the xaml. Is there a way to quickly do it, like the above? Edit: This seems to be the simplest/quickest thing I can come up with, anything inherently wrong with it?
[Code]....
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Apr 17, 2010
In a winforms application (VB, VS2008 SP1) i bound a checkbox field to a SQL Server 2005 BIT field. The databinding itself seems to work, there is this litte problem: user creates a new record and checks the checkbox, then the user decides to create a new record (without having saved the previous, so there are 2 new records to be submitted) and checks also the second.
[Code]...
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Oct 19, 2009
I have a custom control with a bindable property:-
Private _Value As Object
<Bindable(True), ... > _
Public Property Value() As Object
Get
[code]....
Also, here, I'm adding a handler to the DataBindings.CollectionChanged event.This is the second place that I retrieve the type:-
Private Sub DataBindings_CollectionChanged(ByVal sender As Object, ByVal e As System.ComponentModel.CollectionChangeEventArgs)
If e.Action = CollectionChangeAction.Add Then
Dim b As Binding = DirectCast(e.Element, Binding)
[code]....
I need the first place, because the BindingContextChanged event is not fired until some time after InitializeComponent.The second place is needed if the binding field is programatically changed.Am I handling the correct events here, or is there a cleaner way to do it?
Note: My GetValueType method uses the CurrencyManager.GetItemProperties....etc, to retrieve the type.
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Feb 25, 2011
I have done research on how to manually create sorting in a grid-view and none of it is thorough enough for me to follow. I need more of a step by step solution, like what event should my sorting code go in, how would i enable the headers to allow sorting. normally, i just have .net do this but for some reason this time it doesn't allow it, maybe because i am not using a datasource.that's my code that creates a datable and then binds to the gridview.
Function toptable()
Dim reader As SqlDataReader
cmd.Parameters.AddWithValue("@yeartoget", DropDownList1.SelectedValue)
[code].....
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Mar 15, 2012
I need to develop CATIA addin using Visual Basic. Does anyone have CATIA programming help or user manual?
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Jan 15, 2012
You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near and I don't know how does this happen because whenever I check the SQL that I have made including the inserted data, it shows no error.
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Mar 13, 2009
I have my application set up with ClickOnce. It has been successfully published to my web site. I don't have updates performed automatically but on demand. I have a button that the user can click if they want to check if an update is available and install the update if it is. Here's the
[Code]...
After clicking the button a message box appears and says, "Update is available for download" as you would expect but after clicking the ok on the message box my application goes into a not responding state and I have to close it with the task manager. The application builds successfully and I have a reference for System.Deployment added to the project. Everything in my application works fine as long as I don't try to do an update. Any suggestions on what I should check or do? It should actually say "no updates are available for download" since the version of the program that is being used is the most current version.
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Jan 28, 2009
I have a DataGridView on a form in VB 2005 Express, of the 10 columns i need on this DGV 6 of them will be pulled from an MSSQL DB and 4 of them i need to manually enter. One thing i have going for me (i think) is that the 4 manual columns have the same data in each row.I have been filling this DGV using a datatable, but i am not figuring out how to add manual columns and databound ones in the same DGV. My column layout would look like this:[code]some one please explain to me how i would do something like this. if you can include the datatable definitions also it would be a big help, in order for me to verify that i am at least doing that the right way.
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Feb 5, 2012
want to write a program that would have 4 boxes on the menu console:
Box 1) User input ( Ask the user to enter a number)
Box 2) Random Value
Box 3) Rolls value
Box 4) Counter
I want to write a If statement that shows the values of the rolls and the the counter count each time the user enters a number. If however I press the random box, a randomized number between 0-50 is generated and the counted is incremented by 1.
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Apr 22, 2009
trying to automate some manual tasks. The task to access a web page (asp) login and then get some details from the site. The challenge is that the home page after login is build of 3 frames. when i see the page view source from the edit menu all i see are frame names. Once i right click on each frame and view source i am able to see the complete source - variables javascript function etc. The following code helps me to navigate :
vb.net
Set ie = CreateObject("internetexplorer.Application")
Dim s As String[code]....
After this the page has been logged in. Now to proceed further i have to click a "image" object.
1) I tried qualifying the image like ie.Document..........item("img1").click this doesn't work
2) I tried calling the javascript function directly
ie.Document.all.Item("frame1").Document.parentwindow.execScript "JS_WGorUsers (funcname)", "javascript"
The 1st option gives a run time error and 2nd option says access denied. (if i login manually i am able to click the image.
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Apr 29, 2009
I had an idea to embed a PDF document into my application somehow.The PDF is a copy of the user manual. I expect that the file will be around 20 KB. This way, if people don't distribute the PDF with my app, they can extract it whenever they need to.
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Jan 8, 2009
[Code]...
And have been trying things, but haven't found how to get it fire. At run time when I look at the value of the @Appid paramter it has the first row's value so it doesn't appear to be that.
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Jan 9, 2009
I have a form that I just want to pop up right above the time on the lower right side of the screen. Does anyone know how to set a manual start position?
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Apr 15, 2011
I am looking to download several files from several FTP sites. Most of the time these files are all present by 08:00, but occasionally they are not there until a little later.Currently we have a bunch of excel sheets where the user goes into each and clicks a button which connects to the relevent ftp sites and downloads the files, performs some manipulation on them and then reports back to the user if the files exist, are empty, or if all is well.I am looking to redesign this, and was thinking I would encompass this within a Windows service which would have some sort of timer functionality which would start at about 7am, and end when all the files were downloaded whereby it would 'sleep' till the next business day.On the task completion it would send an email giving the information that was present in the current excel spereadsheets.
One thing with this is how often to poll the ftp sites to see if the files are there. I would ideally like to poll about once every 15 minutes or 1/2 hour, but if the user knows the file is present then they want to be able to invoke my process.One way of accomplishing this was to make the service a WCF windows service, so that it would run normally, and then if the user sends a request for amanual override, then the service would ignore its timer and run the process then an there.
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Jan 8, 2009
Code:
dim Insert as string="insert into acaps(AppId,activity_dt,activity_cd,process_state,UserId,SeqNbr,LocCode,comments) values (@AppId,@activity_dt,@activity_cd,@process_state,@UserId,@SeqNbr,@LocCode,@comments)"
Dim x As New Odbc.OdbcDataAdapter(selectQ.ToString, DirectCast(Me._Cn, Odbc.OdbcConnection))
If x.InsertCommand Is Nothing Then
[code].....
And have been trying things, but haven't found how to get it fire. At run time when I look at the value of the @Appid paramter it has the first row's value so it doesn't appear to be that.
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Apr 26, 2012
i have an application running on VS2010 and i'm using sql server 2008 r2. "Employee" table holds employees bio data, i can draw org chart using MS visio 2010 manual,i need to draw the org chart in Visio format from the VB.net application.
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Jun 17, 2010
I am using the NPV() function in VB.NET to get NPV for a set of cash flows. However, the result of NPV() is not consistent with my results performing the calculation manually (nor the Investopedia NPV calc... which matches my manual results)
My correct manual results and the NPV() results are close, within 5%.. but not the same...
Manually, using the NPV formula:
NPV = C0 + C1/(1+r)^1 + C2/(1+r)^2 + C3/(1+r)^3 + .... + Cn/(1+r)^n
The manual result is stored in RunningTotal
[Code]...
The MSDN page example clearly states that the initial expense should be included in the cash flows list.
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Jul 1, 2009
How are volume(s) created? Is it a manual or automatic process?
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Jul 2, 2009
What's the best Object Browser / Syntax Training Manual? Looking for a good reference guide which helps me understand what I'm seeing with the object browser.
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Jul 28, 2009
This is my first post. I have just started some serious .NET programming. Can anyone help me understand what is a good, industry standard in developing the VB.NET or ASP.NET applications? Should we use the Automatically generated code by the VStudio or we should be coding manually i.e. handling the datasets, populating the controls etc instead of using the automatic generated code using wizards.
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Nov 18, 2010
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
' Make the data array.
Dim people(3) As Person
people(0) = New Person("Ann", "Able")
people(1) = New Person("Ben", "Baker")
people(2) = New Person("Cindy", "Carruthers")
[CODE]...
Above is my code for vb.net to plotting the array list into datagridview. It is success to plotting, but why the datagridview unable to manual add row after plotting?
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Jul 5, 2011
I have an explorer-like interface which in many ways mimiques the behaviour of a standard explorer window. What I need is to find some way of knowing if something had changed in the filesystem since the last time I checked.What I mean, for example if a user creates a directory or renames a file - I need a way to know that. Right now I re-read the contents of the displayed folder once per second and I added a manual 'Refresh' button, but I wonder if there is a better solution.I tried to use FileSystemWatcher component for that but either I couldn't figure out how it works or it doesn't have such functionality.
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Feb 8, 2010
I would like to manually access and update an Access Database without using bound user interface objects
For example:
1) Open the Database (eg: AJAXMAIN.ACCDB)
2) Create a Dataset of one of the tables in the database (eg: Contacts)
3) Loop through all records in that table and edit one of the fields
4) Update the table while completing the edit of each record.
While the code for doing this in VB6 is eazy peazy the code for doing it in VB2008 escapes.
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Aug 16, 2011
I am not a .net programmer but I can write bits and pieces that I need, however, I have been having trouble working out the best way to achieve something for a website I'm altering.I basically need to have a drop down list which is bound to a certain SQL call (already in place) but I also need the ability to manually type into the drop down list for items that do not exist. These items do not need to be entered into the SQL (I can handle the additional data separately) but I cannot find a way to type inside a drop down list while it is bound to a datasource.Some entries in the datasource (SQL table) are used for one thing, but then a text string needs to be entered for optional entries which do not exist within this SQL table.
Does anyone know how I can achieve this or maybe another similar control can be used that offers this kind of functionality?**Update to be more clear:I need this at runtime. For instance, I do not need this to be within code I actually need the control to accept user input when someone is on the webpate.Imagine a shopping list and all the items are within the drop down list then the user wants to add another item to the shopping list so they just type it into the drop down box and submit the page and its value will be used instead of an existing item.
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Mar 25, 2011
When I place data into the list box, I would like the new information to be visible at the bottom of the list without having to have the user use the scroll bar to see it. The data should scroll up automatically as new data is placed into the listbox. Can this be done?
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Jul 30, 2010
I'm building an application for run in PPC. Is my first for this kind of equipment. At a time, I nedd to fill a datagrid, by one manual select. In VB forms it works perfectly, but I can't convert this for PPC forms. I use this
[Code]...
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