This is a very basic question. I have a grid, whose data context is bound to a entity framework service. I simply bound the context to service and I can see the data that is getting bound properly. Now, I want to change couple of coulmns to special controls. Like one column has true or false value and that column I want to display a radio button. One column is date value, I want to display date control. How would one go about doing it?
Thanks.
I'm not exactly sure how to do the Radio Button portion of this, but something like this may get you started:
<ListBox x:Name="LayoutRoot" ItemsSource="{Binding Collection}">
<ListBox.ItemTemplate>
<DataTemplate>
<StackPanel Orientation="Horizontal">
<TextBlock Text="{Binding Text}"/>
<CheckBox Content="True" IsChecked="{Binding Checked, Mode=TwoWay}"/>
</StackPanel>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
In this case, you would have a checkbox being bound to the boolean value. I'm not exactly sure what you are using for a date control, but you should be able to place that in the stackpanel also and bind it to the dateproperty of your item.
In the above example, 'Collection' is an observable collection of 'MyObject' which is shown below:
MyObject.cs
public class MyObject
{
public string Text { get; set; }
public bool Checked { get; set; }
public bool InverseChecked { get; set; }
public DateTime Date { get; set; }
}
I also understand that you were using a grid, and I'm showing a ListBox. Not sure if this would work for you, but this is how we've approached it in the past.
Hope this helps!
Related
I am trying to make a program that gives you a CRUD interface for List of any objects you give it. That includes:
Showing all of their properties inside a ListBox
The ability to insert a new object
The ability to update an object
The ability to delete an object
Keep in mind that, at the compile-time, I have no idea what kind of objects I am getting. For example, I want to have a TextBlock for each of the properties simply listed inside ListBox's DataTemplate. So how would I do the data binding if I don't know the name of the property? Also, how would I generate an insertion form when I don't know property names?
And finally, is it possible to do it using pure MVVM Pattern, without any Code-Behind?
Thanks
One option: Wrap PropertyInfo in a PropertyInfoViewModel so you can bind to it's value:
class PropertyInfoViewModel
{
Object CRUDObject { get; set; }
PropertyInfo PropertyInfo { get; set; }
Object Value {
get
{
return PropertyInfo.GetValue(CRUDObject);
}
set
{
PropertyInfo.SetValue(CRUDObject, value);
}
}
}
You could have an ObservableCollection in your CRUDObjectViewModel, populated when you create it or change the CRUD it's attached to (Look up reflection if confused by this).
Use a template selector to choose a particular editor to display for the PropertyInfoViewModel:
public class PropertyTypeTemplateSelector : DataTemplateSelector
{
public DataTemplate BooleanTemplate { get; set; }
public DataTemplate GuidTemplate { get; set; }
public DataTemplate StringTemplate { get; set; }
public override DataTemplate SelectTemplate(object item, DependencyObject container)
{
PropertyInfo propertyInfo = (item as PropertyInfoViewModel).PropertyInfo;
if (propertyInfo.PropertyType == typeof(Boolean))
{
return BooleanTemplate;
}
else if (propertyInfo.PropertyType == typeof(Guid))
{
return GuidTemplate;
}
else if (propertyInfo.PropertyType == typeof(String))
{
return StringTemplate;
}
return null;
}
}
You could use it like this:
<ListBox ItemsSource="{Binding Properties}">
<ListBox.Resources>
<DataTemplate x:Key="BooleanTemplate">
<CheckBox Content="{Binding PropertyInfo.Name}" IsChecked="{Binding Value}"/>
</DataTemplate>
<DataTemplate x:Key="GuidTemplate">
<StackPanel>
<TextBox Text="{Binding PropertyInfo.Name}"/>
<TextBox Text="{Binding Value, ValueConverter={StaticResources MyGuidConverter}}"/>
</StackPanel>
</DataTemplate>
<DataTemplate x:Key="StringTemplate">
<StackPanel>
<TextBox Text="{Binding PropertyInfo.Name}"/>
<TextBox Text="{Binding Value}"/>
</StackPanel>
</DataTemplate>
<DataTemplate x:Key="Null"/>
</ListBox.Resources>
<ListBox.ItemTemplateSelector>
<helpers:PropertyTypeTemplateSelector BooleanTemplate="{StaticResource BooleanTemplate}"
GuidTemplate="{StaticResource GuidTemplate}"
StringTemplate="{StaticResource StringTemplate}"/>
</ListBox.ItemTemplateSelector>
</ListBox>
Might have to think about how to deal with changes/updates though, as this isn't using NotifyPropertyChanged to keep the UI up to date.
I've not tested any of this, but it should work, I think.
This control WPFCrudControl may fit with your problem.
A generic WPF CrudControl implemented based on the MVVM pattern. It gives a huge productivity boost for straightforward CRUD operations (Add, Edit, Delete, Validate, Listing with sorting, paging and searching). The control abstracts both the UI and business logic, so it requires relatively minimal coding effort, while keeping it possible to customize its behavior.
I have a ComboBox bound to a collection of objects defined as this.
public class TierOption
{
public string Option { get; set; }
public Type DataType { get; set; }
}
public class TierOptions : ObservableCollection<Tier1Option>
{
}
I have 3 other controls related to this ComboBox, which are a TextBox, ComboBox, or a WPFToolKit:DatePicker.
I need to show only the related control which corresponds to the datatype(Type) of the object selected in the first ComboBox and neither of the others.
Pseudo Code Example:
(Probably too close to butchered C# but hopefully it conveys the idea)
switch (ComboBox.SelectedItem.DataType)
{
case String:
TextBox.Visibility = Visibility.Visible;
ComboBox.Visibility = Visibility.Hidden;
DatePicker.Visibility = Visibility. Hidden;
break;
case DateTime:
TextBox.Visibility = Visibility.Hidden;
ComboBox.Visibility = Visibility.Hidden;
DatePicker.Visibility = Visibility. Visible;
break;
<...so forth and so on...>
}
My attempts have resulted in very non-wpf looking convoluted messes which don't work regardless. Being new to wpf I'm trying very hard to stay true to the best design practices.
Thank you!
You can play with DataTemplate with DataType property
<...Resources>
<DataTemplate DataType="{x:Type sys:String}">
<TextBox Text="{Binding}"/>
</DataTemplate>
<DataTemplate DataType="{x:Type DateTime}">
<DatePicker .../>
</DataTemplate>
...
</...Resources>
<ContentControl Content="{Binding SelectedItem, ElementName=myComboBox}"/>
<ComboBox ItemsSource="{Binding ...}"/>
The code above is just the idea, you could have to make adjustements. For example you won't be able to modify a string item itself (you could have to encapsulate each item of your list)
If your list contains all items of the same type, you can use a ContentTemplateSelector on contentControl.
ContentControl Content="{Binding SelectedItem, ElementName=YourCombBox}" ContentTemplateSelector="{StaticResource YourTemplateSelector}"
MSDN DOC about ContentControl.ContentTemplateSelector Property
Bind to the detail visibility to ElementName=ComboBox Path=SelectedItem.DataType. And you will need to use a converter that returns visibility. You will need two converters return opposite answers. If you have more than 2 combination then some more in the line of Jonas.
I assumed Type was a system class and it appears to be a custom class. Extend that class to have additional properties. Even if Type was a system type you could just create a class that implements it and extend it.
public Visibility TextBoxVisibility { get; }
public Visibility ComboBoxVisibility { get; }
...
Then on TextBox bind the visibility
Visisbility="{binding ElementName=Combobox Path=SelectedItem.DataType.TextBoxVisibility]";
I'm new to WPF and before I dive in solving a problem in completely the wrong way I was wondering if WPF is clever enough to handle something for me.
Imagine I have a collection containing objects. Each object is of the same known type and has two parameters. Name (a string) and Picked (a boolean).
The collection will be populated at run time.
I would like to build up a UI element at run time that will represent this collection as a series of checkboxes. I want the Picked parameter of any given object in the collection updated if the user changes the selected state of the checkbox.
To me, the answer is simple. I iterate accross the collection and create a new checkbox for each object, dynamically wiring up a ValueChanged event to capture when Picked should be changed.
It has occured to me, however, that I may be able to harness some unknown feature of WPF to do this better (or "properly"). For example, could data binding be employed here?
I would be very interested in anyone's thoughts.
Thanks,
E
FootNote: The structure of the collection can be changed completely to better fit any chosen solution but ultimately I will always start from, and end with, some list of string and boolean pairs.
I would strongly recommend the ItemsControl, its behaviour is as close as you can get to the ASP.Net repeater control so it is very flexible.
Declare the item control as:
<ItemsControl Name="YourItemsControl"
ItemsSource="{Binding Path=YourCollection}"
ItemTemplate="{StaticResource YourTemplate}">
</ItemsControl>
Then you can use the datatemplate to organise the data into a display format for the user
<DataTemplate x:Key="ProjectsTemplate">
<StackPanel Margin="0,0,0,10">
<Border CornerRadius="2,2,0,0" Background="{StaticResource ItemGradient}" d:LayoutOverrides="Width, Height">
<local:ItemContentsUserControl Height="30"/>
</Border>
...
Useful ItemsControl Links
http://drwpf.com/blog/itemscontrol-a-to-z/
http://www.galasoft.ch/mydotnet/articles/article-2007041201.aspx
I hope this helps you.
You can use Data Templates. Here's a good post about it.
This is exactly the kind of scenario WPF simplifies. Event-handlers- bah! Data-binding and data templates make this a cinch. I have constructed an example illustrating how you can do this.
Here is the code-behind, which declares a class to represent your items- PickedItem. I then create a collection of these items and populate it with some samples.
public partial class DataBoundCollection : Window
{
public DataBoundCollection()
{
Items = new ObservableCollection<PickedItem>();
Items.Add(new PickedItem("Item 1"));
Items.Add(new PickedItem("Item 2"));
Items.Add(new PickedItem("Item 3"));
InitializeComponent();
}
public ObservableCollection<PickedItem> Items
{
get;
set;
}
}
public class PickedItem
{
public PickedItem(string name)
{
Name = name;
Picked = false;
}
public string Name
{
get;
set;
}
public bool Picked
{
get;
set;
}
}
Now, let's look at the XAML mark-up for this window:
<Window x:Class="TestWpfApplication.DataBoundCollection"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="DataBoundCollection" Height="300" Width="300"
DataContext="{Binding RelativeSource={RelativeSource Self}}">
<Grid>
<ListBox ItemsSource="{Binding Items}">
<ListBox.ItemTemplate>
<DataTemplate>
<StackPanel Orientation="Horizontal">
<CheckBox IsChecked="{Binding Picked}" Margin="5"/>
<TextBlock Text="{Binding Name}" VerticalAlignment="Center"/>
</StackPanel>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
</Grid>
I create a ListBox to hold the items, and bind its ItemsSource property to the collection I created in the code-behind. Then, I provide the ListBox with an ItemTemplate, which determines how each PickedItem will be rendered. The DataTemplate in this case is as simple as a check-box and some text, both bound to the member variables on PickedItem. Now, when I check any of these items, the data in the underlying collection is modified, in real-time, with no event handlers needed. Ta-da!
alt text http://img405.imageshack.us/img405/1083/databoundcollection.png
I have a simple ComboBox in my Silverlight 3 application. I want to populate it from an ObservableCollection. The list holds a class that has a Name(string), and a Selected(bool) property. The combo box has as many items as I have in the list, but I cannot seem to get the list data to appear.
Any help would be appreciated.
<ComboBox x:Name="cmbCategory" Grid.Column="3">
<ComboBox.ItemTemplate>
<DataTemplate>
<StackPanel Orientation="Horizontal">
<TextBlock Text="{Binding Name}"/>
<CheckBox IsChecked="{Binding Selected}"/>
</StackPanel>
</DataTemplate>
</ComboBox.ItemTemplate>
...
private class cmbCategoryClass
{
public string Name { get; set; }
public bool Selected { get; set; }
}
private ObservableCollection<cmbCategoryClass> _categories;
....
cmbCategory.DataContext = _categories;
cmbCategory.ItemsSource = _categories;
I can't tell from your code if this is a Codebehind or a ViewModel. I am guessing that you are actually populating the _categories list in code so that it contains at least one cmbCategoryClass object. Try removing the line that sets the DataContext to _categories as your ItemsSource may be looking for a _categories property on the DataContext Check the Output window in Visual Studio when running in debug mode for clues to data binding failures.
I feel really stupid for asking this but I have been thrashing for over 8 hours. How do I get the Selected Item to show its text in my WPF combo box when selected?
Above is an option dialog that allows users to select and configure the available tournament displays. The problem is the selected combo box item shows the UserControl instead of the Display name.
On Window Loaded:
//_displayer is a private member populated using MEF
//[ImportMany(typeof (IDisplayer))]
//private IEnumerable<IDisplayer> _displayers;
DisplayTypeComboBox.ItemsSource = _displayers;
The ComboBox Xaml:
<ComboBox
Name="DisplayTypeComboBox"
Grid.Column="1"
Grid.ColumnSpan="2"
Grid.Row="1"
IsEditable="False"
SelectionChanged="DisplayTypeComboBox_SelectionChanged">
<ComboBox.ItemTemplate>
<DataTemplate>
<ComboBoxItem Content="{Binding DisplayerName}" />
</DataTemplate>
</ComboBox.ItemTemplate>
</ComboBox>
The IDisplayer:
public interface IDisplayer
{
string DisplayDataLocation { get; set; }
string DisplayerName { get; }
string DisplayerDescription { get;}
bool WatcherEnabled { get; }
UserControl View { get; }
string DisplayerImageLeft { get; set; }
string DisplayerImageRight { get; set; }
void Update();
}
I don't even want to think about how many hours I have spent trying to solve what should be a simple problem. Why is it so hard to get your selected text to appear as the selected value? I give up, WPF you have beat me into submission. I changed the control to a list box it takes up more room to display the selectable Items but at least it works.
<ListBox
Name="DisplayTypeComboBox"
Grid.Column="1"
Grid.ColumnSpan="2"
Grid.Row="1"
SelectionChanged="DisplayType_SelectionChanged">
<ListBox.ItemTemplate>
<DataTemplate>
<Label Content="{Binding DisplayerName}" />
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
I encountered the same thing. Took me a while too. :(
You should have used the ItemContainerStyle and not ItemTemplate.
Because ComboBox wraps the internal items with a ComboBoxItem - you basically wrapped the ComboBoxItem with another one.
Check what DisplayerName member actually contains. Most likely it contains the UserControl name instead of the Display name.
Try using a TextBlock to bind to the DisplayerName instead of a ComboboxItem. I believe that when you set the itemsource, the combo control will wrap the items inside comboboxitems controls automatically.
Edit: I misunderstood your question. Try setting the SelectionBoxItemTemplate.