Simple Databinding - Handle Bound Field/property Change - Winforms / .Net?
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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May 28, 2012
I've got a custom NumericEditor control that has a nullable Decimal property called Value. When I bind a data field to Value, I'd like to retrieve the underlying Type of the data that's bound, so that I can restrict the use of decimal places if the source field is an integral data type.I figure I'd have to do this in the BindingContextChanged event, but how do I get the Type of the data field from the binding itself? My Google-Fu is failing me at the moment.
In short, I'm looking for something like the GetValueType method mentioned in the following question: Simple databinding - How to handle bound field/property change. Winforms, .Net I imagine this method would also be handy if the Value property was an Object.
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Mar 3, 2011
So I'm just trying to understand why someone would want to use the shorthand property instantiation
Public Property CarModel As String <-- property
As opposed to
Public CarModel As String <-- variable
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May 28, 2012
I have written a .Net 4.0 Winforms Numeric Editor control (which inherits from TextBox), and I have added a Value property that is a nullable decimal type, as follows:
Public Class NumericEditor
Inherits TextBox
Private _value As Decimal? = Nothing
[code]....
how to get around this exception, particularly when I'm databinding a number field to a number property, and there should be no string conversion happening. (To further complicate things, I'm using a similar technique for another control where I databind a DateTime field to a nullable DateTime property, and that control works just fine.)
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Mar 12, 2009
I am trying to change a property of a data bound textbox on start up of a form and each time a new record is navigated to. I can't find the a good event to attach this action to.
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Feb 24, 2010
I am building a data based application using VB 2008 an SQL Express. I need to create textboxes on my form using code, (With & End With) method. I need a simple code string that will allow the app to check if the field to wich the textbox wil be databound is Nul, If so the textbox will not be created.
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Jan 15, 2010
on a Windows Form, an object myObject is bound to myObjectDataBindingSource like this:myObjectDataBindingSource .DatSource = myObject on the form, i have a check box bound to the property: chkProp1 for example of the object: myObjectDataBindingSource In the code when the checkbox is clicked, I need to go in code and change another text property of the object txtProper2 for example like this:
Private Sub chkProp1_CheckedChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles chkProp1.CheckedChanged
[code].....
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Aug 4, 2009
I have a datagrid that I am unable to change the width setting, it always reverts back to the original setting.
To change this setting:
1. select the datagrid view tasks
2. Edit columns bound column properties
3. Select Width property
4. Width property will always revert back to the original setting.
I have check the properties settings without any luck.
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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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Oct 19, 2010
I am trying to follow an example. I'm getting the following errors:
1. PartNum is not a member of 'Vantage2.OMSDataContext.
2. Name 'Where' is not declared.
3. Method arguments must be enclosed in parenthesis.
4. Name 'p' is not declared.
5. Comma, ')', or a valid expression continuation expected.
For reference, the link is here: [URL]
I have followed with my code as follows...
Class Window1
Private db As New OMSDataContext
Private View As BindingListCollectionView
Private Sub Window1_Loaded(ByVal sender As Object, ByVal e As System.Windows.RoutedEventArgs) Handles Me.Loaded
[Code] .....
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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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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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Sep 15, 2010
In WinForms, I do a databinding between controls and properties of a Business Object :
txtNote.DataBindings.Add("Text", oZones, "Note") Note is a property of the BO oZones. It is OK. Now I have an array as properties in the BO oZones. In the following sample, this array is IndemType().
[Code]...
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Mar 27, 2010
I have bound TextBoxes. When I edit anything, I have to move to the next or previous record before calling the Update Method for that record to be updated. With my DGV, I use
vb
Me.dgvSalvageListing.EndEdit()
and it will update as expected. So, how would I do something similar to my Simple Controls?
vb
Private Sub UpdateDb()
Try
' Write changes back to db
[code]....
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Nov 26, 2011
I am missing something simple. I know how to bind asp.net datagrids and webforms, but this is my first time trying to bind to an object list of T in a windows form. (I am use to using datasets with datatables and im trying to get away from doing that).I have a simple object list that gets populated on the form load. However if I click a button to add a dummy record the datagridview does not display the new record added. The bindingNavigator (if clicked nextrecord) and "debug stops" all show that the new record I just added to the object list is there.
Even adding the datasource object in the watch list shows the new records are there. They are just not displaying.
I cannot seem to figure out as to why the new record is not being displayed in the datagridview when I can see the record got clearly added to the datasource.
[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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Mar 5, 2011
sir i've one text field and two tables named table1,table2
i've to just display text from two different tables using two different navigations for each table.
1.when i'll click on first navigation, data from first table should have to display in textbox
2. when i'll click on second navigation, data from second table should have to display in same textbox alternatively
i've to show data in only one text box alternatively
i've binded designtime table1 to textbox
so how to unbind it & bind table2 to same texbox runtime.
like that i've 12 tables & 12 navigation for each table and only one text filed
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Apr 23, 2010
I would like to databind to a property that requires arguments.
I thought about defining custom columns and cells because the parameters that the property requires are available from the within the object bound to the row, but I'm having trouble materialising this idea.
As an additional problem, that I think leads on from this, I have also created a custom column and cell for the datagridview that takes the implementation of an interface during it's construction. I have added this column to the datagrid view programmatically (passing the Interface implementation to the column constructor). I've overridden the paint method which evaluates a property from the Interface implantation using arguments from the other rows in the column, but it doesn't seem to call the paint method at all. Even on DataGridView.Refresh(). Essentially I would like this column to also update, evaluate a property from the interface implentation using arguments from the underlying object bound to the row and print this number in the cell.
The reason for this second problem is so that I can implement the interface many different times and just at a column dynamically to display it's evaluation.
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Nov 23, 2010
In this example the IsEnabled property of my button is bound to the selected rows "Local" property of the grid and it works just fine:
<Button DockPanel.Dock="Bottom" Width="100" Height="100" IsEnabled="{Binding ElementName=dataGridRestore , Path=SelectedItem.Local}"></Button>
<my:DataGrid x:Name="dataGridRestore"
ItemsSource="{Binding}"
[Code]...
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Mar 31, 2011
I have developped a usercontrol, but I can't seem to find how to databind on a property of the usercontrol in a detailsview.[code]
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Nov 27, 2010
I seem to be having a problem binding the visibility property of a textbox to a database value using the advanced binding property.I found this article (BUG: Inconsistent behavior when you bind the Visible property of a Windows Form control to a Boolean field) stating there is a bug in some ol
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Dec 7, 2011
I'm trying to create a Window with a ListView and an Area where details to the selected Object are displayed. The Listview displays items stored in an ObservableCollection(Of T) Collection. The items itself contain also an ObservableCollecton(Of T) Collection which should then be displayed in the details area in another ListView, accordingly to the selected item of the first ListView.
The Problem: The InitializeComponent() throws an Exception (XAMLParseException).
Exception:Set property 'System.Windows.Controls.GridViewColumn.DisplayMemberBinding' threw an exception.
InnerException:Object of type 'System.String' cannot be converted to type 'System.Windows.Data.BindingBase'.
The Line- and ColumNumer of the Exception are Pointing at the <GridView> of my ListView (.View).This is the First ListView
<ListView ItemsSource="{Binding Path=MyObjectCollection, Mode=OneWay}" SelectedItem="{Binding Path=Selected, Mode=OneWayToSource}">
<ListView.View>[code]....
So. How can I bind to the Collection Property of an Object could be nothing?
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Sep 8, 2009
I have an app that downloads from a networked SQL database to a dataset and also to an XML file on laptops. Laptop users will take their executable and the XML file which the local dataset will read.Although I can get gridviews etc to bind to that dataset syntax such as
"TextBox1.DataBindings.Add("Text", ds, "fname")"
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Jan 25, 2010
I am a newbie at ASP.net and after using sqldatasource with a listview to insert and show results from an SQL server db I want to try using the LINQ datasource since it seems to be more flexible in codebehind.
My problem is this: I droped a listview control to the page and I created the Linq datasource in codebehind with vb. the issue that I am having when I ..Select d.columms name i get the error system.string does not contain a property with the name "columname".. if i ommit the column name then its works fine.. the funny part is the d.count works fine but after that i get the error.. please see my code below:
[Code]...
b.dbMake needs to work so that i can use Distinct ,, ia m using asp.net version:3.5 and IIS version 7.0 ..
not sure what i am missing ,, but i did try alot of approaches,,1- checked the web.config file and it seems to have two assemblies and two namespaces for LINQ..2- used different databinding syntaxs,,and i searched a lot for the solution.. the last one i read the person ommited the name of the column,, i thought that wasnt the best solution.. also my dbMake column is comming up in the "intellisence"
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Apr 26, 2012
I am creating an Extended DateTime picker. I have created a Class the inherits the Default DateTimePicker and Adds a new Property NullableValue. I have placed the control on a form and bound it to a Binding Source using the NullableValue Property. When I load the record the control updates as it should. But when I change the value and save it does not save back to the database.
[Code]...
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Dec 5, 2009
I seem to be having a problem binding the visibility property of a textbox to a database value using the advanced binding property.
I found this article (BUG: Inconsistent behavior when you bind the Visible property of a Windows Form control to a Boolean field) stating there is a bug in some older versions of the .net framework.
Does anyone know if this has been fixed in 4.0?
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Dec 13, 2009
I'm trying to format a datetime field to just show the date. The datetime is bound to an asp:label and for the Text attribute I have tried the following....
Text= String.Format("{0:D}", '<%# Bind("CReviewDate") %>')
and
Text= String.Format("{0:D}", <%# Bind("CReviewDate") %>)
[code]....
In all cases I get a green wavy line under the equation and the tip help says "Validation (ASP.Net): If this attribute value is enclosed in quotation marks, the quotation marks must match.
String.Format("{0:D}", DateTime.Now)
is the syntax that I have been told should work.
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Dec 23, 2009
How to get the handle of a ListBox control in VB.NET 2005?
I am using
Dim i_Handle As ListBox
i_Handle = ListBox1.Handle
But this is not working
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