Does anyone know how to dynamically set the ElementName for textblock.text binding?
I have two Datagrids that have the same information but the second DataGrid is just a filter of the same datasource, but what I want is to bind text of a textblock to the selected item depending if the item was clicked in the main datagrid or the secondary datagrid.
I have the below code to bind the textblock to one datagrid but I would also like the same to happen if the user clicked an item in the secondDataGrid.
Is this possible?
<TextBlock Margin="29,0" Text="{Binding SelectedItem.Name, ElementName=MainDataGrid}"
It is possible, though I don't think this is the proper solution.
You can handle one of the DataGrids' events in the code-behind, where in the handler you can write the following code:
BindingOperations.SetBinding(textBlock, TextBlock.TextProperty,
new Binding("SelectedItem.Name")
{
ElementName = "DataGrid1"
});
Basically you reset the Binding on the TextBlock's Text property with this code, where:
textBlock is the name of your TextBlock;
with TextBlock.TextProperty you define that you want to work with the Text property on the TextBlock;
The third paramter is the new Binding itself. The constructor takes the Path of the Binding and then in the "body" I set the ElementName.
If DataGrid1 fires the event you set the ElementName to that DataGrid's name, if DataGrid2 fires the event then you set the ElementName to the second DataGrid's name.
SelectionChanged can be a good event to handle on both DataGrid, but if you want the TextBlock to update when you selected and element in the first then select another one in the second and then click back to the first element to update then you need to handle the GotFocus event as well.
Play a little bit with it and you will see what I mean.
My working example:
private void SetBindingOnTextBlock(string elementName)
{
BindingOperations.SetBinding(textBlock, TextBlock.TextProperty, new Binding("SelectedItem.Name")
{
ElementName = elementName
});
}
private void DataGrid_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
SetBindingOnTextBlock("DataGrid1");
}
private void DataGrid_SelectionChanged_1(object sender, SelectionChangedEventArgs e)
{
SetBindingOnTextBlock("DataGrid2");
}
private void DataGrid1_GotFocus(object sender, RoutedEventArgs e)
{
SetBindingOnTextBlock("DataGrid1");
}
private void DataGrid2_GotFocus(object sender, RoutedEventArgs e)
{
SetBindingOnTextBlock("DataGrid2");
}
UPDATE 1:
Set
IsSynchronizedWithCurrentItem="True"
on the DataGrids and it may solve your problem if ItemsSources are the same. (Not sure if this is what #dkozl meant) Originally I assumed that they are different.
Related
I have a textbox and several custom controls. Each of the custom controls has a "hint text" property that should appear in the textbox when that control is hovered over.
In winforms I was able to just give the custom control a textbox property and change its text property with events, however in WPF it instead makes a new textbox when I give it a property.
So how can I get the desired functionality?
Assuming your custom controls all inherit from a common base type (which I have called CustomControl as an example)...
XAML:
<TextBox x:Name=TextBox/>
<Button VerticalAlignment="Bottom" Click="ButtonBase_OnClick" MouseEnter="UIElement_OnMouseEnter" MouseLeave="UIElement_OnMouseLeave">test</Button>
Code behind:
private void UIElement_OnMouseEnter(object sender, MouseEventArgs e)
{
TextBox.Text = ((CustomControl) sender).HintText;
}
private void UIElement_OnMouseLeave(object sender, MouseEventArgs e)
{
TextBox.Text = string.Empty;
}
I am trying to bind the IsEnabled property of a button to properties of the window's CollectionViewSource. I am doing this to implement First/Previous/Next/Last buttons and want the First and Previous to be disabled when the view is on the first item etc.
I have the collection view source set up, UI controls binding to it correctly, with access to its view in code so the click event handlers work fine in navigating through the view.
<CollectionViewSource x:Key="cvMain" />
The DockPanel is the root element of the window
<DockPanel DataContext="{StaticResource cvMain}">
FoJobs is an observable collection, cvJobs is a CollectionView that I use in the button's click handler
private void Window_Loaded(object sender, RoutedEventArgs e) {
((CollectionViewSource)Resources["cvMain"]).Source = FoJobs;
cvJobs = (CollectionView)((CollectionViewSource)Resources["cvMain"]).View;
}
I have tried this but get a binding error "BindingExpression path error: '' property not found on 'object' ''ListCollectionView'"
<Button Name="cbFirst" Click="cbMove_Click" IsEnabled="{Binding Source={StaticResource cvMain}, Converter={StaticResource CurrPos2BoolConverter}}" />
I am trying to do with a converter first but figure a style with triggers would be more efficient, but cant get access to the collection view. Even though the underlying datacontext is set to a collection view source, the binding is passed to the converter as the view's source (if I dont explicity set the binding's Source, as above), which has no currency properties (CurrentPosition, Count etc).
Any help would be greatly appreciated.
Why don't you use a RoutedCommand for this(even if you don't use MVVM that is)?
say something like:
<Button x:Name="nextButton"
Command="{x:Static local:MainWindow.nextButtonCommand}"
Content="Next Button" />
and in your code-behind:
public static RoutedCommand nextButtonCommand = new RoutedCommand();
public MainWindow() {
InitializeComponent();
CommandBinding customCommandBinding = new CommandBinding(
nextButtonCommand, ExecuteNextButton, CanExecuteNextButton);
nextButton.CommandBindings.Add(customCommandBinding); // You can attach it to a top level element if you wish say the window itself
}
private void CanExecuteNextButton(object sender, CanExecuteRoutedEventArgs e) {
e.CanExecute = /* Set to true or false based on if you want button enabled or not */
}
private void ExecuteNextButton(object sender, ExecutedRoutedEventArgs e) {
/* Move code from your next button click handler in here */
}
You can also apply one of the suggestions from Explicitly raise CanExecuteChanged() to manually re-evaluate Button.isEnabled state.
This way your encapsulating logic relating to the button in one area.
I am writing a data entry application and am having problems dealing with add vs edit vs view 'modes' of the app.
The scenario: From a window, the user selects items in two combo boxes and then clicks a button. If the combo box selections don't match an existing record, the form should open with a new record ready to have values inserted. If the selections DO match an existing record, this record should be opened with all the textboxes in the form in 'Readonly' mode. Should the user wish to modify the existing data, they click the form's Edit button which sets the textboxes as 'Editable'.
I'm new to wpf, but in my vba apps, I'd normally have a DataMode property and a ToggleControls method which would loop through the TabControl's TabItems and then loop through the TabItems' controls, setting the IsReadOnly property of any TextBox controls found based on the 'DataMode' property. However, I have doubts about whether this is the path to follow in wpf.
So, my question is, do i use the approach above? If so, how do I access the controls in a TabItem. This doesn't work: foreach (Control ctrl in MyTabCtrl) { //if Textbox do stuff }.
If this isn't the way to do it, can someone show me the way? I'm guessing it's either a template / style issue or something to do with setting the data as readonly somehow, and then binding the TextBox's IsReadOnly property to the state of the data. Edit: Oh, or that ViewStateManager thing. All of which i know little about.
An easy approach would be
In Code behind declare a DependencyProperty named IsReadOnly
public static readonly DependencyProperty IsReadOnlyProperty = DependencyProperty.Register(
"IsReadOnly",
typeof (bool),
typeof (MainWindow)
);
public bool IsReadOnly
{
get { return (bool) GetValue(IsReadOnlyProperty); }
set { SetValue(IsReadOnlyProperty, value); }
}
Implement the Buttons Click event, so that IsReadOnly gets false on Click
private void Button_Click(object sender, RoutedEventArgs e)
{
IsReadOnly = false;
}
Bind the TextBoxes to the IsReadonly property using DataBinding
<TextBox IsReadOnly="{Binding Path=IsReadOnly, RelativeSource={RelativeSource Mode=FindAncestor, AncestorType=Window}, Mode=OneWay}" />
This binding assumes that your code behind is not your DataContext and you therefore have to bind relatively to the Window/ UserControl which the CodeBehind is applied to.
This way the TextBoxes listen to changes on this property. When it switches, they change their ReadOnly state automatically.
You can use DataContext :
Bind the datacontext of your tabControl to your record (with the button event click write
this.Canvas.DataContext = _yourRecord for sample)
public void bntEvent_Click(object sender, EventArgs e)
{
// Do matching and put the result in result field
MyTabCtrl.DataContext = false;
}
Bind IsReadOnly/IsEnable property of your textboxs on your datacontext and use a converter to return true/false value
<TextBox IsReadOnly="{Binding .}" />
See http://msdn.microsoft.com/en-us/library/system.windows.data.ivalueconverter.aspx for more informations about Converters.
I hope I help you and you understand my bad English.
Good bye
I have a WPF TreeView with a HierarchicalDataTemplate.
Currently I have to double click an item to expand/collapse it.
I would like to change this behaviour to a single click, without loosing other functionality. So it should expand and collapse on click.
What is the recommended way to do this?
Thanks!
You could use a re-templated checkbox as your node (containing whatever template you are currently using) with its IsChecked property bound to the IsExpanded property of the TreeViewItem.
Here is a template I've just test that seems to do the job:
<HierarchicalDataTemplate ItemsSource="{Binding Items}">
<CheckBox IsChecked="{Binding RelativeSource={RelativeSource AncestorType=TreeViewItem}, Path=IsExpanded}">
<CheckBox.Template>
<ControlTemplate>
<TextBlock Text="{Binding Header}"></TextBlock>
</ControlTemplate>
</CheckBox.Template>
</CheckBox>
</HierarchicalDataTemplate>
Just replace the ControlTemplate contents with whatever you need.
If you are using a standard TreeViewItem, then you can capture the click event:
private void OnTreeViewMouseUp( object sender, MouseButtonEventArgs e )
{
var tv = sender as TreeView;
var item = tv.SelectedItem as TreeViewItem;
if( item != null )
item.IsExpanded = !item.IsExpanded;
e.Handled = true;
}
private void OnTreeViewPreviewMouseDoubleClick( object sender, MouseButtonEventArgs e )
{
e.Handled = true;
}
Most likely in your case, you'll need to do something with your binding and ViewModel. Here's a good article from CodePlex: Simplifying the WPF TreeView by Using the ViewModel Pattern.
Just use selected item changed event and use the following,
private void treeview_SelectedItemChanged(object sender, RoutedPropertyChangedEventArgs<object> e)
{
TreeViewItem item = (TreeViewItem)treeview.SelectedItem;
item.IsExpanded = true;
}
where treeview is the name of your TreeView, you could include an if to close/open based on its current state.
I have very little experience working with WPF to this point, so I am not 100% certain here. However, you might check out the .HitTest method of both the Treeview and TreeView Item (the WPF Treeview is essentially the Windows.Controls.Treeview, yes? Or a derivation thereof?).
THe HIt Test method does not always automatically appear in the Intellisense menu for a standard Windows.Forms.Treeview (I am using VS 2008) until you type most of the method name. But it should be there. You may have to experimnt.
You can use the .HitTest Method to handle the MouseDown event and return a reference to the selected treeview item. You must test for a null return, however, in case the use clicks in an area of the control which contains no Tree Items. Once you have a reference to a specific item, you should be able to set its .expanded property to the inverse of whatever it is currently. again, some experimentation may be necessary here.
As I said, I have not actually used WPF yet, so I could have this Wrong . . .
The answer of Metro Smurf (thanks to which I got where I wanted to be) suggests the right approach . You could simply hook up to the SelectedItemChanged event of the Treeview. Then cast the e.NewValue passed in the eventhandler as TreeViewItem, and access its IsExpanded property to set it to true.
void MyFavoritesTreeView_SelectedItemChanged(object sender, RoutedPropertyChangedEventArgs<object> e)
{
((TreeViewItem)e.NewValue).IsExpanded = true;
}
Then for the final touch, you can also hook up the items in your Treeview by casting them as TreeViewItem as suggested, and then you can hook up to the various manipulation events, like:
var item = tv.SelectedItem as TreeViewItem;
item.Expanded += item_Expanded;
And then do whatever you need to do in the eventhandler
void item_Expanded(object sender, RoutedEventArgs e)
{
// handle your stuff
}
I am implementing a file upload tool using Silverlight. In this I can browse for files and when I select a file then it is bound to a datagrid. In the datagrid I have a template column with a button to delete the particular item from the datagrid and ItemSource of the datagrid which is a List<>.
I have a class UploadedFiles as below.
public class UploadedFiles
{
public FileInfo FileInf{get;set;}
public int UniqueID{get;set;}
public string FileName{get;set;}
public string FileExtension{get;set;}
public long FileSize{get;set;}
}
I am using a datagrid with a templatecolumn like below with ItemSource set as List<UploadedFiles>
<data:DataGridTemplateColumn Width="100">
<data:DataGridTemplateColumn.CellTemplate>
<DataTemplate>
<Button Click="btn_Click" Content="Del" Width="45"/>
</DataTemplate>
</data:DataGridTemplateColumn.CellTemplate>
</data:DataGridTemplateColumn>
and the button click event handler is
private void btn_Click(object sender, System.Windows.RoutedEventArgs e)
{
/* I need to access the particular list item based on the datagrid
row in which the clicked button resides.*/
}
I need to access the particular list item based on the datagrid row in which the clicked button resides and remove the item from the List<UploadedFiles> and rebind the datagrid.
Thanks
Two things to look at here:
Firstly, to get the individual UploadedFiles object, cast the sender to a Button (or FrameworkElement) and access the DataContext property. The DataContext will be the UploadedFiles row (you will need to cast again from object).
Secondly, rather than removing the item from the list and rebinding, have you considered using an ObservableCollection instead? If you use that, removing the row will automatically remove it from the DataGrid without needing you to rebind.
private void btn_Click(object sender, System.Windows.RoutedEventArgs e)
{
var uploadedFiles = (UploadedFiles)((FrameworkElement)sender).DataContext;
//access collection and remove element
}