I would like to know how to bind a custom data type to a TreeView.
The data type is basically an arraylist of objects that contain other arraylists. Access would look something like this:
foreach (DeviceGroup dg in system.deviceGroups)
{
foreach (DeviceType dt in dg.deviceTypes)
{
foreach (DeviceInstance di in dt.deviceInstances)
{
}
}
}
I would like the TreeView to look something like this:
DeviceGroup1
--> DeviceType1
--DeviceInstance1
--DeviceInstance2
--> DeviceType2
--DeviceInstance1
DeviceGroup2
--> DeviceType1
--DeviceInstance1
--> DeviceType2
Ok this is where the HierarchicalDataTemplate will save you. The trick is you will need to use two different hierarchical templates, since you have a three-level hierarchy here. I have constructed a simple UserControl to illustrate. First, here is some code-behind creating model data similar to what you have:
public partial class ThreeLevelTreeView : UserControl
{
public ArrayList DeviceGroups { get; private set; }
public ThreeLevelTreeView()
{
DeviceInstance inst1 = new DeviceInstance() { Name = "Instance1" };
DeviceInstance inst2 = new DeviceInstance() { Name = "Instance2" };
DeviceInstance inst3 = new DeviceInstance() { Name = "Instance3" };
DeviceInstance inst4 = new DeviceInstance() { Name = "Instance4" };
DeviceType type1 = new DeviceType() { Name = "Type1", DeviceInstances = new ArrayList() { inst1, inst2 } };
DeviceType type2 = new DeviceType() { Name = "Type2", DeviceInstances = new ArrayList() { inst3 } };
DeviceType type3 = new DeviceType() { Name = "Type3", DeviceInstances = new ArrayList() { inst4 } };
DeviceType type4 = new DeviceType() { Name = "Type4" };
DeviceGroup group1 = new DeviceGroup() { Name = "Group1", DeviceTypes = new ArrayList() { type1, type2 } };
DeviceGroup group2 = new DeviceGroup() { Name = "Group2", DeviceTypes = new ArrayList() { type3, type4 } };
DeviceGroups = new ArrayList() { group1, group2 };
InitializeComponent();
}
}
public class DeviceGroup
{
public string Name { get; set; }
public ArrayList DeviceTypes { get; set; }
}
public class DeviceType
{
public string Name { get; set; }
public ArrayList DeviceInstances { get; set; }
}
public class DeviceInstance
{
public string Name { get; set; }
}
Nothing difficult here, but note that you should use ObservableCollection instead of ArrayList if you want to add and remove from your collections dynamically. Now let's look at the XAML for this control:
<UserControl x:Class="TestWpfApplication.ThreeLevelTreeView"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="clr-namespace:TestWpfApplication"
DataContext="{Binding RelativeSource={RelativeSource Self}}">
<TreeView ItemsSource="{Binding DeviceGroups}">
<TreeView.ItemTemplate>
<HierarchicalDataTemplate ItemsSource="{Binding DeviceTypes}">
<HierarchicalDataTemplate.ItemTemplate>
<HierarchicalDataTemplate ItemsSource="{Binding DeviceInstances}">
<TextBlock Text="{Binding Name}"/>
</HierarchicalDataTemplate>
</HierarchicalDataTemplate.ItemTemplate>
<TextBlock Text="{Binding Name}"/>
</HierarchicalDataTemplate>
</TreeView.ItemTemplate>
</TreeView>
And here is the result:
alt text http://img684.imageshack.us/img684/6281/threeleveltreeview.png
I lately had to deal with a similar issue and after much research was able to get to a good generic solution. My problem was a bit more generic: Visualize a .NET object's properties in a tree view.
So given this class
```
class Person
{
public string FirstName { get; set; }
public string LastName { get; set; }
public List<Person> Children { get; set; }
}
I should see a tree like for an example instance:
- root
- FirstName: John
- LastName: Smith
- Children:
- [0]
- FirstName: Ann
- LastName: Smith
```
It's rather difficult to use reflection and go over an object's properties and such. Luckily, we already have a library that does that - Newtonsoft.Json.
My trick is to serialize the object with Newtonsoft.Json, then deserialize with System.Web.Script.Serialization.JavaScriptSerializer.
JavaScriptSerializer returns ArrayLists and Dictionaries, which are pretty simple to go over and add to the tree.
Thanks to this article which gave me some of the concept ideas.
Anyway, here's the entire code:
In XAML:
<TreeView ItemsSource="{Binding TreeItemsSource}">
<TreeView.Resources>
<HierarchicalDataTemplate DataType="{x:Type local:TreeNode}" ItemsSource="{Binding Path=Children}">
<TreeViewItem>
<TreeViewItem.Header>
<StackPanel Orientation="Horizontal" Margin="-10,0,0,0">
<TextBlock Text="{Binding Path=Name}"/>
<TextBlock Text=" : "/>
<TextBox Text="{Binding Path=Value}" IsReadOnly="True"/>
</StackPanel>
</TreeViewItem.Header>
</TreeViewItem>
</HierarchicalDataTemplate>
</TreeView.Resources>
</TreeView>
In ViewModel:
public IEnumerable<TreeNode> TreeItemsSource
{
get
{
TreeNode tree = TreeNode.CreateTree(SelectedSession);
return new List<TreeNode>() { tree };
}
}
And the TreeNode class
public class TreeNode
{
public string Name { get; set; }
public string Value { get; set; }
public List<TreeNode> Children { get; set; } = new List<TreeNode>();
public static TreeNode CreateTree(object obj)
{
JavaScriptSerializer jss = new JavaScriptSerializer();
var serialized = Newtonsoft.Json.JsonConvert.SerializeObject(obj);
Dictionary<string, object> dic = jss.Deserialize<Dictionary<string, object>>(serialized);
var root = new TreeNode();
root.Name = "session";
BuildTree2(dic, root);
return root;
}
private static void BuildTree2(object item, TreeNode node)
{
if (item is KeyValuePair<string, object>)
{
KeyValuePair<string, object> kv = (KeyValuePair<string, object>)item;
TreeNode keyValueNode = new TreeNode();
keyValueNode.Name = kv.Key;
keyValueNode.Value = GetValueAsString(kv.Value);
node.Children.Add(keyValueNode);
BuildTree2(kv.Value, keyValueNode);
}
else if (item is ArrayList)
{
ArrayList list = (ArrayList)item;
int index = 0;
foreach (object value in list)
{
TreeNode arrayItem = new TreeNode();
arrayItem.Name = $"[{index}]";
arrayItem.Value = "";
node.Children.Add(arrayItem);
BuildTree2(value, arrayItem);
index++;
}
}
else if (item is Dictionary<string, object>)
{
Dictionary<string, object> dictionary = (Dictionary<string, object>)item;
foreach (KeyValuePair<string, object> d in dictionary)
{
BuildTree2(d, node);
}
}
}
private static string GetValueAsString(object value)
{
if (value == null)
return "null";
var type = value.GetType();
if (type.IsArray)
{
return "[]";
}
if (value is ArrayList)
{
var arr = value as ArrayList;
return $"[{arr.Count}]";
}
if (type.IsGenericType)
{
return "{}";
}
return value.ToString();
}
}
Related
I have a JSON, like the image below:
I have a ComboBox inside a ListView. I want to display "pairs" in the ComboBox.
XAML:
<ListView Name="ListPairOption">
<ListView.ItemTemplate>
<DataTemplate x:DataType="data:PairClass">
<StackPanel
x:Name="pilganStack">
<WebView
x:Name="option"
local:MyProperties.HtmlString="{Binding Name}"/>
</StackPanel>
<ComboBox
x:Name="pairOption"
DisplayMemberPath="NameA"
SelectedValue="{Binding ComboBoxClass, Mode=TwoWay}"
ItemsSource="{x:Bind PilihanS}"
PlaceholderText="Pilih" />
</ListView
Codes:
try
{
JsonObject jsonObject = JsonObject.Parse(jsonText);
JsonObject questionObject = jsonObject["EXAM_QUESTION"].GetObject();
ObservableCollection<PairClass> itemL = new ObservableCollection<PairClass>();
JsonArray mapArray = questionObject["map"].GetArray();
foreach (JsonValue mapValue in mapArray)
{
JsonArray mapArrayI = mapValue.GetArray();
PairClass pair = new PairClass();
foreach (JsonValue mapValueI in mapArrayI)
{
try
{
string v = mapValueI.ToString();
pair.Name = v;
}
}
}
itemL.Add(pair);
}
JsonArray pairArray = questionObject["pairs"].GetArray();
string pairString = "";
foreach (JsonValue pairValue in pairArray)
{
JsonArray pairArrayI = pairValue.GetArray();
List<ComboBoxClass> PilihanS = new List<ComboBoxClass>();
foreach (JsonValue pairValueI in pairArrayI)
{
try
{
var collection = Regex.Matches(v, "\\\"(.*?)\\\"");
foreach (var item in collection)
{
string v3 = item.ToString().Trim('"');
pairString = v3;
}
}
}
PilihanS.Add(new ComboBoxClass() { NameA = pairString });
}
ListPairOption.ItemsSource = itemL;
}
PairClass:
public class PairClass
{
public string Name { get; set; }
public ObservableCollection<ComboBoxClass> PilihanS { get; set; }
public PairClass(string name)
{
Name = name;
}
}
public class ComboBoxClass
{
public string NameA { get; set; }
public override string ToString()
{
return this.NameA;
}
}
}
From the code above, I didn't succeed in displaying it into a ComboBox in a ListView so that the ComboBox is empty, as shown below:
How to display it into a ComboBox?
From the code above, I didn't succeed in displaying it into a ComboBox in a ListView so that the ComboBox is empty, as shown below:
If you want to access the property that out of DataType, please using Binding ElementName=Control Name then access the the outside property from the parent DataContext. please note you need to set current page DataContext as this this.DataContext = this;. it could make sure you can access PilihanS where in the code behind from DataTemplate.
<ComboBox
x:Name="pairOption"
ItemsSource="{Binding DataContext.PilihanS, ElementName=ListPairOption}"
PlaceholderText="Pilih" />
code behind
public MainPage()
{
this.InitializeComponent();
this.DataContext = this;
}
public List<ComboBoxClass> PilihanS { get; set;} = new List<ComboBoxClass>();
And delete this line where in your code above List<ComboBoxClass> PilihanS = new List<ComboBoxClass>();
I have a collection ConversationModel that have two models in it. I want to get the value of the very first item of the collection. I tried this code var obj = ConversationCollection.First(); to get the value but it always returns null. Here the model's property is populated but outside of it. How can I get those values
public class ConversationModel
{
public SendMessageModel SMM { get; set; }
public ReceivedMessageModel RMM { get; set; }
}
Here's how I create my collection:
ObservableCollection<ConversationModel> cm = new ObservableCollection<ConversationModel>();
foreach (DataRow convo in dataTable.Rows)
{
string _messageID = (string)convo["MessageID"];
string message = (string)convo["UserMessage"];
string username = (string)convo["FromUser"];
DateTime datetime = (DateTime)convo["MessageDateTime"];
string messageStatus = (string)convo["MessageStatus"];
string mdt = "";
if (datetime.Date == DateTime.Now.Date) mdt = datetime.ToString("t");
if (username == ClientUsername)
{
SendMessageModel smm = new SendMessageModel
{
MessageIdentifier = _messageID,
UserDisplayName = ClientDisplayName,
SendMessage = message,
MessageTime = mdt,
MessageStatus = (Status)Enum.Parse(typeof(Status), messageStatus)
};
cm.Add(new ConversationModel { SMModel = smm });
}
else
{
ReceivedMessageModel rmm = new ReceivedMessageModel
{
MessageIdentifier = _messageID,
ClientDisplayName = RecipientDisplayName,
MessageTime = mdt,
ReceivedMessage = message
};
cm.Add(new ConversationModel { RMM = rmm });
}
}
ConversationCollection = cm;
My WPF Code for the ItemsControl
<ItemsControl ItemsSource="{Binding ConversationCollection}">
<ItemsControl.Resources>
<DataTemplate DataType="{x:Type Models:ReceivedMessageModel}">
<UserControls:RecievedMessageBubble/>
</DataTemplate>
<DataTemplate DataType="{x:Type Models:SendMessageModel}">
<UserControls:SendMessageBubble />
</DataTemplate>
</ItemsControl.Resources>
</ItemsControl>
If ConversationCollection is an ObservableCollection<ConversationModel>, it can only contain ConversationModels which is why neither of your data templates will be applied.
If you change its type to for example ObservableCollection<object>, you could add both ReceivedMessageModels and SendMessageModels to it.
You will then be able to retrive the first item by casting:
var receivedMessageModel = ConversationCollection[0] as ReceivedMessageModel;
if (receivedMessageModel != null)
{
//the first item is a ReceivedMessageModel
}
else
{
var sendMessageModel = ConversationCollection[0] as SendMessageModel;
// the first item is A SendMessageModel
}
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So, I'm at a lost, and hope for some guidance. I'm using MVVM pattern and EF.
My View contains a datagrid bound to a observable collection within the view model.
The UI has furthermore 3 comboboxes with possible data to minimize the data shown.
So I've been googling around and found nothing I could use (or might not have understood it correctly).
How do I search and select the items from a ObservableCollection, and update the datagrid accordingly?
public ObservableCollection<DimTargets> TargetParameters { get; set; }
private void SelectionChanged(object obj)
{
if (obj is FactTargets)
{
SelectedFactTarget = (FactTargets)obj;
}
else if (obj is DimLocation)
{
SelectedLocation = (DimLocation)obj;
ViewCollection.Select(x => x.Location == SelectedLocation.Location);
TargetParameters.Where(x => x.FactTargets == SelectedLocation.FactTargets);
}
else //DimBladeType
{
SelectedBladeType = (DimBladeType)obj;
int[] a = DimTargetsController.ReturnBladeType(SelectedBladeType);
foreach (int i in a)
{
TargetParameters.Single(k => k.ID == i);
}
var os = TargetParameters.Where(d => d.ID == );
TargetParameters = Convert<DimTargets>(os);
//TargetParameters.Where(ka => ka.ID == a);
//TargetParameters = new ObservableCollection<DimTargets>(TargetParameters.Where(t => t.FactTargets == SelectedBladeType.FactTargets));
//var obs = TargetParameters.Where(t => t.FactTargets == SelectedBladeType.FactTargets);
//TargetParameters = Convert<DimTargets>(obs);
//ViewCollection.Select(x => x.BladeType == SelectedBladeType.BladeType).ToList();
}
}
public ObservableCollection<T> Convert<T>(IEnumerable original)
{
return new ObservableCollection<T>(original.Cast<T>());
}
XAML:
ComboBox ItemsSource="{Binding FactTargetCollection, Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}" SelectedItem="{Binding SelectedFactTarget}" DisplayMemberPath="FYQuater" Behaivor:SelectionChangedBehaviour.Command="{Binding SelectionChangedCommand}"/>
<ComboBox ItemsSource="{Binding LocationCollection, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" SelectedItem="{Binding SelectedLocation}" DisplayMemberPath="Location" Behaivor:SelectionChangedBehaviour.Command="{Binding SelectionChangedCommand}"/>
<ComboBox ItemsSource="{Binding BladeTypeCollection, Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}" SelectedItem="{Binding SelectedBladeType}" DisplayMemberPath="BladeType" Behaivor:SelectionChangedBehaviour.Command="{Binding SelectionChangedCommand}"/>
<Button Content="Submit" Style="{StaticResource BaseButtonStyle}"></Button>
</StackPanel>
<StackPanel x:Name="WorkPanel" DockPanel.Dock="Right">
<DataGrid ItemsSource="{Binding TargetParameters}">
</DataGrid>
</StackPanel>`
Hope this gives a better idea of what i'm trying to do.
the c# code are filled with examples with what i've tried.
Cant see all of you objects but here is a quick n simple illustration...
public RelayCommand<int> FilterAgeCommand { get; set; }
public Base_ViewModel()
{
FilterAgeCommand = new RelayCommand<int>(OnFilterAgeCommand);
this.TestClassList = new ObservableCollection<TestClass>();
this.TestClassList.Add(new TestClass() { FName = "John", SName = "Doe", Age = 25 });
this.TestClassList.Add(new TestClass() { FName = "Jane", SName = "Doe", Age = 75 });
this.TestClassList.Add(new TestClass() { FName = "Mick", SName = "Doe", Age = 35 });
this.TestClassList.Add(new TestClass() { FName = "Harry", SName = "Doe", Age = 10 });
this.TestClassList.Add(new TestClass() { FName = "Linda", SName = "Doe", Age = 25 });
this.TestClassList.Add(new TestClass() { FName = "Fred", SName = "Doe", Age = 14 });
this.FilteredTestClassList = new ObservableCollection<TestClass>();
this.Age = new List<int>();
for(int i = 1; i <100; i++)
{
this.Age.Add(i);
}
}
private void OnFilterAgeCommand(int obj)
{
this.FilteredTestClassList = Convert<TestClass>((from tc in this.TestClassList where tc.Age < obj select tc).ToList());
}
public List<int> Age { get; set; }
public ObservableCollection<TestClass> TestClassList { get; set; }
private ObservableCollection<TestClass> _FilteredTestClassList;
public ObservableCollection<TestClass> FilteredTestClassList
{
get { return _FilteredTestClassList; }
set { _FilteredTestClassList = value; OnPropertyChanged("FilteredTestClassList"); }
}
public ObservableCollection<T> Convert<T>(IEnumerable original)
{
return new ObservableCollection<T>(original.Cast<T>());
}
A simple class for the demo...
public class TestClass : INotifyPropertyChanged
{
private string _FName;
public string FName
{
get { return _FName; }
set { _FName = value; NotifyPropertyChanged("FName"); }
}
private string _SName;
public string SName
{
get { return _SName; }
set { _SName = value; NotifyPropertyChanged("FName"); }
}
private int _Age;
public int Age
{
get { return _Age; }
set { _Age = value; }
}
public event PropertyChangedEventHandler PropertyChanged;
private void NotifyPropertyChanged(String info)
{
if (PropertyChanged != null)
{
PropertyChanged(this, new PropertyChangedEventArgs(info));
}
}
}
And some XAML...
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:ViewModels="clr-namespace:_36550006.ViewModels"
xmlns:Views="clr-namespace:_36550006.Views"
xmlns:i="clr-namespace:System.Windows.Interactivity;assembly=System.Windows.Interactivity"
xmlns:ei="clr-namespace:Microsoft.Expression.Interactivity.Core;assembly=Microsoft.Expression.Interactions"
Title="Base_View" Height="300" Width="300">
<Window.DataContext>
<ViewModels:Base_ViewModel/>
</Window.DataContext>
<Grid>
<StackPanel>
<DataGrid ItemsSource="{Binding FilteredTestClassList, NotifyOnSourceUpdated=True}"></DataGrid>
<ComboBox x:Name="cmb" ItemsSource="{Binding Age}" SelectedValuePath="{Binding Age}" >
<i:Interaction.Triggers>
<i:EventTrigger EventName="SelectionChanged">
<i:InvokeCommandAction Command="{Binding FilterAgeCommand}" CommandParameter="{Binding ElementName=cmb, Path=SelectedItem}"/>
</i:EventTrigger>
</i:Interaction.Triggers>
</ComboBox>
</StackPanel>
</Grid>
I essentially have two ObservableCollection, the first holds ALL of your items and the second is a filtered collection that you bind to....
I have main combobox (Categories) and depended combobox (Subcategories). I want it to display SelectedItems when window opens. All works fine in .Net 4.0, but it doesn't work in .Net 4.5. I have two computeres with these .Net versions.
In .net 4.5. only main combobox displays SelectedItem, depended doesn't. How can I fix it?
I made test project to all of you who're interested, just copy and paste. I have no idea how I can make it smaller, sry. But it is simple, clear code example 100% generates the problem.
XAML:
<Window x:Class="GridTest.TestWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:Converter="clr-namespace:GridTest"
Title="TestWindow"
Height="300"
Width="300">
<Window.Resources>
<Converter:CategoryConverter x:Key="CategoryConverter"/>
</Window.Resources>
<Grid>
<DataGrid Name="_dataGrid"
CanUserAddRows="False"
AutoGenerateColumns="False">
<DataGrid.Columns>
<DataGridTemplateColumn Width="*">
<DataGridTemplateColumn.CellTemplate>
<DataTemplate>
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition/>
<ColumnDefinition/>
</Grid.ColumnDefinitions>
<ComboBox Grid.Column="0"
Name="_categories"
ItemsSource="{Binding Categories}"
DisplayMemberPath="Name"
SelectedItem="{Binding SelectedCategory, UpdateSourceTrigger=PropertyChanged, Mode=TwoWay}">
</ComboBox>
<ComboBox Grid.Column="1"
SelectedItem="{Binding SelectedSubcategory, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"
DisplayMemberPath="Name">
<ComboBox.ItemsSource>
<MultiBinding Converter="{StaticResource CategoryConverter}">
<Binding Path="Subcategories"/>
<Binding Path="SelectedItem"
ElementName="_categories"/>
</MultiBinding>
</ComboBox.ItemsSource>
</ComboBox>
</Grid>
</DataTemplate>
</DataGridTemplateColumn.CellTemplate>
</DataGridTemplateColumn>
</DataGrid.Columns>
</DataGrid>
</Grid>
</Window>
Code:
public class CategoryConverter : IMultiValueConverter
{
public object Convert(object[] values, Type targetType, object parameter, CultureInfo culture)
{
if (values[0] == null) return null;
var subcategories = values[0] as List<Subcategory>;
if (subcategories == null) return null;
var category = values[1] as Category;
if (category == null) return subcategories;
return subcategories.Where(g => g.CategoryId == category.Id);
}
public object[] ConvertBack(object value, Type[] targetTypes, object parameter, CultureInfo culture)
{
throw new NotImplementedException();
}
}
public enum CategoryKinds
{
Car = 0,
Fruit = 1,
}
public class Category
{
public Int32 Id { get; set; }
public String Name { get; set; }
public override Boolean Equals(object obj)
{
var c = obj as Category;
if (c == null) return false;
return Id == c.Id;
}
}
public class Subcategory
{
public Int32 Id { get; set; }
public String Name { get; set; }
public Int32 CategoryId { get; set; }
public override Boolean Equals(object obj)
{
var sc = obj as Subcategory;
if (sc == null) return false;
return Id == sc.Id;
}
}
public class DataGridItem
{
public List<Category> Categories { get; set; }
public Category SelectedCategory { get; set; }
public List<Subcategory> Subcategories { get; set; }
public Subcategory SelectedSubcategory { get; set; }
public DataGridItem()
{
Categories = new List<Category>
{
new Category
{
Id = (Int32)CategoryKinds.Car, Name = "Car"
},
new Category
{
Id = (Int32)CategoryKinds.Fruit, Name = "Fruit"
}
};
Subcategories = new List<Subcategory>
{
new Subcategory
{
Id = 1,
Name = "Volvo",
CategoryId = (Int32) CategoryKinds.Car
},
new Subcategory
{
Id = 2,
Name = "Nissan",
CategoryId = (Int32) CategoryKinds.Car
},
new Subcategory
{
Id = 3,
Name = "Banana",
CategoryId = (Int32)CategoryKinds.Fruit
},
new Subcategory
{
Id = 4,
Name = "Lemon",
CategoryId = (Int32)CategoryKinds.Fruit
},
};
}
}
/// <summary>
/// Interaction logic for TestWindow.xaml
/// </summary>
public partial class TestWindow : Window
{
public List<DataGridItem> GridItems { get; set; }
public TestWindow()
{
InitializeComponent();
DataContext = this;
GridItems = new List<DataGridItem>
{
new DataGridItem
{
SelectedCategory = new Category
{
Id = (Int32)CategoryKinds.Car, Name = "Car"
},
SelectedSubcategory = new Subcategory
{
Id = 2,
Name = "Nissan",
CategoryId = (Int32) CategoryKinds.Car
}
},
new DataGridItem
{
SelectedCategory = new Category
{
Id = (Int32)CategoryKinds.Fruit, Name = "Fruit"
},
SelectedSubcategory = new Subcategory
{
Id = 4,
Name = "Lemon",
CategoryId = (Int32) CategoryKinds.Car
}
}
};
_dataGrid.ItemsSource = GridItems;
}
}
UPDATE
With approach suggested by Ilan and charly_b code will work fine.
GridItems = new List<DataGridItem>
{
new DataGridItem(),
new DataGridItem()
};
GridItems[1].SelectedCategory = GridItems[1].Categories[0];
GridItems[1].SelectedSubcategory = GridItems[1].Subcategories[1];
GridItems[0].SelectedCategory = GridItems[0].Categories[1];
GridItems[0].SelectedSubcategory = GridItems[0].Subcategories[3];
This code will result to:
Fruit - Lemon
Car - Nissan
But I have solution that will work even if you set SelectedItem that don't belong to ItemsSource of Combobox. You can override GetHashCode method like this:
public override int GetHashCode()
{
return Name.GetHashCode();
}
Obviously, in .Net 4.5 some of WPF methods operating with searching SelectedItem in Combobox's ItemsSource have different implementation from .Net 4.0 and now they use GetHashCode method :)
Try the next changes, the best practice is to use the source collection items in order to define the selected item. Firstly it is an architectural error to use a new item to define the selection (in both 4.5 and 4 dot.net versions). And second I advice you to use the mvvm approach (including INotifyPropertyChange implementation) to develop wpf related applications, and then all selection logic have to be moved to ViewModel and separated from the code behind (xaml.cs files).
public MainWindow()
{
InitializeComponent();
DataContext = this;
var f = new DataGridItem();
var firstselectedCategory = f.Categories.FirstOrDefault();
if (firstselectedCategory != null)
{
f.SelectedCategory = firstselectedCategory;
f.SelectedSubcategory =
f.Subcategories.FirstOrDefault(subcategory => subcategory.CategoryId == firstselectedCategory.Id);
}
else
{
f.SelectedCategory = null;
f.SelectedSubcategory = null;
}
var s = new DataGridItem();
var secondSelectedCategory = s.Categories.FirstOrDefault(category => !Equals(category, f.SelectedCategory));
if (secondSelectedCategory != null)
{
s.SelectedCategory = secondSelectedCategory;
s.SelectedSubcategory =
s.Subcategories.FirstOrDefault(subcategory => subcategory.CategoryId == secondSelectedCategory.Id);
}
else
{
s.SelectedCategory = null;
s.SelectedSubcategory = null;
}
GridItems = new List<DataGridItem>
{
f,s,
};
#region
//GridItems = new List<DataGridItem>
//{
// new DataGridItem
// {
// SelectedCategory = new Category
// {
// Id = (Int32) CategoryKinds.Car,
// Name = "Car"
// },
// SelectedSubcategory = new Subcategory
// {
// Id = 2,
// Name = "Nissan",
// CategoryId = (Int32) CategoryKinds.Car
// }
// },
// new DataGridItem
// {
// SelectedCategory = new Category
// {
// Id = (Int32) CategoryKinds.Fruit,
// Name = "Fruit"
// },
// SelectedSubcategory = new Subcategory
// {
// Id = 4,
// Name = "Lemon",
// CategoryId = (Int32) CategoryKinds.Fruit
// }
// }
//};
#endregion
_dataGrid.ItemsSource = GridItems;
}
The xaml code was not changed.
How it looks like:
.
I'll be glad to help if will have problems with the code.
Regards.
The Combobox SelectedItem object must be contained inside the Combobox's ItemsSource List.
In order to make your Programm work you can replace the SelectedSubCategory Property with the following code: (I would not use it like this in the production code, but it demonstrates how it works)
private Subcategory SelectedSubcategoryM;
public Subcategory SelectedSubcategory
{
get
{
return this.SelectedSubcategoryM;
}
set
{
this.SelectedSubcategoryM = (from aTest in this.Subcategories
where aTest.Id == value.Id
select aTest).Single();
}
}
I have 2 related tables - CarMarks and CarMarkGroups. Any CarMark has CarMarkGroupID. I have edit form for CarMarks with combobox binding to CarMarkGroups.
I mark one of CarMarkGroup as deleted record. So, this marked CarMarkGroup is not in list binding to combobox (because I must show only active CarMarkGroups). But CarMarkGroupID in selected CarMark still links to marked as deleted CarMarkGroup. And i dont need to change this link.
But I need show this record for selected CarMark even if it was marked for deletion. What is the best practice for that? Need I build list for combobox in ChangeSelection Event? Or what?
I'd propose a solution, based on ICollectionView filtering.
View models:
public class GroupViewModel
{
public string Name { get; set; }
public bool IsDeleted { get; set; }
}
public class ItemViewModel
{
public ItemViewModel(List<GroupViewModel> groups)
{
Groups = new ListCollectionView(groups)
{
Filter = g =>
{
var group = (GroupViewModel)g;
return !group.IsDeleted || (Group == group);
}
};
}
public string Name { get; set; }
public GroupViewModel Group
{
get { return group; }
set
{
if (group != value)
{
group = value;
Groups.Refresh();
}
}
}
private GroupViewModel group;
public ICollectionView Groups { get; private set; }
}
public class ListViewModel
{
private readonly List<GroupViewModel> groups;
public ListViewModel()
{
// some sample initialization
groups = new List<GroupViewModel>
{
new GroupViewModel { Name = "Friuts" },
new GroupViewModel { Name = "Animals" },
new GroupViewModel { Name = "Trees", IsDeleted = true }
};
Items = new List<ItemViewModel>
{
new ItemViewModel(groups) { Name = "Orange", Group = groups[0] },
new ItemViewModel(groups) { Name = "Apple", Group = groups[0] },
new ItemViewModel(groups) { Name = "Banana", Group = groups[0] },
new ItemViewModel(groups) { Name = "Cat", Group = groups[1] },
new ItemViewModel(groups) { Name = "Dog", Group = groups[1] },
new ItemViewModel(groups) { Name = "Bird", Group = groups[1] },
new ItemViewModel(groups) { Name = "Oak", Group = groups[2] },
new ItemViewModel(groups) { Name = "Nut-tree", Group = groups[2] },
new ItemViewModel(groups) { Name = "Pine", Group = groups[2] },
};
}
public IEnumerable<ItemViewModel> Items { get; private set; }
}
View (it's a Window content in WPF Application project):
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition />
<ColumnDefinition />
</Grid.ColumnDefinitions>
<DataGrid x:Name="ItemsGrid" AutoGenerateColumns="False" ItemsSource="{Binding Items}">
<DataGrid.Columns>
<DataGridTextColumn Header="Name" Binding="{Binding Name}"/>
<DataGridTextColumn Header="Group" Binding="{Binding Group.Name}"/>
</DataGrid.Columns>
</DataGrid>
<ContentControl Grid.Column="1" Content="{Binding SelectedItem, ElementName=ItemsGrid}">
<ContentControl.ContentTemplate>
<DataTemplate>
<ComboBox Height="20" ItemsSource="{Binding Groups}" SelectedItem="{Binding Group}">
<ComboBox.ItemTemplate>
<DataTemplate>
<TextBlock Text="{Binding Name}"/>
</DataTemplate>
</ComboBox.ItemTemplate>
</ComboBox>
</DataTemplate>
</ContentControl.ContentTemplate>
</ContentControl>
</Grid>
Code-behind:
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
DataContext = new ListViewModel();
}
}
So, when item is selected, ComboBox contains all non-deleted groups PLUS group of selected item, if this group is deleted.
I am not sure i understand the connections exactly but if you still need to see that CarMarkGroup in your CarMarks ComboBox, maybe add a boolean flag in your CarMarkGroup, something like ProposedForDeletion and when that changes to true, you change some color or another element in the GUI to let the user now it was proposed for deletion, or even display a message regarding this somewhere. Do not delete it from the ObservableCollection but just mark its flag to true and keep it there and do your further check according to this new flag.