I have difficulties binding the selectedindex of a combobox to an object.
This is my code:
(Part of) CustomerClass
public class Customer : INotifyPropertyChanged
{
public int CountryCode
{
get { return _CountryCode; }
set { _CountryCode = value; NotifyPropertyChanged(); }
}
}
2a. (Part of) CustomListItem
<ComboBox x:Name="cboCountryCode" Grid.Column="5" ItemsSource="{Binding}" DisplayMemberPath="LongName" SelectedIndex="{Binding CountryCode, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"/>
2b. (Part of) CustomListItem
public partial class CustomerListItem : UserControl
{
public CustomerListItem()
{
InitializeComponent();
ObservableCollection<CountryCode> Liste = CountryCodes.Instance.List;
cboCountryCode.DataContext = Liste;
}
(Part of) MainPage
<ItemsControl Name="itcCustomers" Style="{StaticResource ItemsControlVirtualizedStyle}">
<ItemsControl.ItemTemplate>
<DataTemplate>
<local:CustomerListItem/>
</DataTemplate>
</ItemsControl.ItemTemplate>
</ItemsControl>
The Combobox List Items are shown correctly.
But the selected index is not working at all
See this screenshot
I found the problem. I tried to bind the Combobox to two different Datasources. One for the collection and one for the selectedindex. Now I combinde these two Datasources into one class and bound to it, now it works fine
Related
I have a WPF user control bound to EmployeeDeductionViewModel with a DataGrid bound to an ObservableCollection of state tax parameters:
public ObservableCollection<Models.StateTaxParmModel> StateTaxSettings
{
get { return _stateTaxSettings; }
set
{
if (_stateTaxSettings != value)
{
_stateTaxSettings = value;
OnPropertyChanged();
}
}
}
Here is the binding on the datagrid (shortened to make it easier to read):
<DataGrid ItemsSource="{Binding Path=StateTaxSettings}" SelectedItem="{Binding Path=StateTaxSetting, Mode=TwoWay}"...
Inside each StateTaxParamModel is a list of possible values the ComboBox needs to bind to:
public ObservableCollection<ParamValue> Values
{
get { return _values; }
set
{
if (_values != value)
{
_values = value;
OnPropertyChanged();
}
}
}
The ParamValue class is really simple:
public class ParamValue
{
public int ValueID { get; set; }
public string ValueText { get; set; }
}
However, the list of possible Values (List of ParamValue) varies with each row. Therein lies the problem. I can bind a ComboBox inside of a DataGrid as long as the list is part of the UserControl DataContext but because the list varies with each row, I can't bind it to the main DataContext, I have to bind it to the ObservableCollection of Values (List of ParamValue) that's unique to each row. Can anyone please help me understand how this is accomplished?
Here is my DataGridTemplateColumn where I'm trying to bind to the row:
<DataGridTemplateColumn Header="Value" MinWidth="60">
<DataGridTemplateColumn.CellTemplate>
<DataTemplate>
<TextBlock Text="{Binding Path=Value, Mode=OneWay}" ToolTip="The value of the state tax parameter for the employee."/>
</DataTemplate>
</DataGridTemplateColumn.CellTemplate>
<DataGridTemplateColumn.CellEditingTemplate>
<DataTemplate>
<ComboBox ItemsSource="{Binding Path=Values, Mode=OneWay}" DisplayMemberPath="ValueText" SelectedValuePath="ValueText" SelectedValue="{Binding Path=Value, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged, ValidatesOnNotifyDataErrors=True, NotifyOnValidationError=True}" />
</DataTemplate>
</DataGridTemplateColumn.CellEditingTemplate>
</DataGridTemplateColumn>
Will had the right idea and in fact, that's where the list of values was located. As it turns out, everything laid out in my question is correct, I just wasn't populating the list of possible values at the right time. Lists work much better when there's something in the list! You'd think I'd know that after 18 years of doing this! ;-)
Have a WPFDatagrid binded to combobox using Datagridtemplatecolumn. Finding difficult to get the selectedItem of the combobox binding. Have found similar examples around but that's not resolving my problem.
Please find the code snippet of my XAML and the data structure below:
public class X
{
public X ()
{
abc = new ObservableCollection<P>();
}
public ObservableCollection<P> Y
{
get { return abc; }
set { abc = value; PropertyChanged("Y"); }
}
}
public class P
{
private string id;
private string name;
public string ID
{
get
{
return id;
}
set
{
id = value;
InvokePropertyChanged("ID");
}
}
public string Name
{
get
{
return name;
}
set
{
name = value;
InvokePropertyChanged("Name");
}
}
}
I have a datastructure defined above that implements the INotifyPropertychanged interface.
<controls:DataGrid Name="datagrid" AutoGenerateColumns="False" ItemsSource="{Binding XList}" Grid.Row="0"
SelectedItem="{Binding SelectedX, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}">
<controls:DataGrid.Columns>
<controls:DataGridTemplateColumn Header="Yl">
<controls:DataGridTemplateColumn.CellTemplate>
<DataTemplate>
<ComboBox ItemsSource="{Binding Y}"
IsSynchronizedWithCurrentItem="False" DisplayMemberPath="Name"
SelectedValue="{Binding Path=SelectedY, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged, NotifyOnTargetUpdated=True}"
SelectedValuePath="SelectedY"
SelectedItem="{Binding SelectedY, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" />
</DataTemplate>
</controls:DataGridTemplateColumn.CellTemplate>
</controls:DataGridTemplateColumn>
</controls:DataGrid.Columns>
</controls:DataGrid>
Now, in view model, have a observablecollection of List of X i.e., XList and that is binded to the datagrid in the XAML. and have Y within each row of the datagrid binded to the Combobox. Have a property as SelectedY, binded to the SelectedItem of the combobox.
Have also a property as SelectedX binded to the selectedItem of the datagrid, which works fine.
Issue is not able to get the Selected Item binding of the Combobox. Not able to set the selected item for the combobox when the selection has changed.
Can anybody help me out to set the selecteditem binding of the combo box?
Where is set your datacontext ?
You can do something like that :
<controls:UserControl x:Name=MainControl>
<controls:UserControl.DataContext>
<classpath:X/>
</controls:UserControl.DataContext>
<controls:DataGrid ItemsSource={Binding YourItemsContainer}>
<controls:DataGrid.Columns>
<controls:DataGridComboBoxColumn ItemsSource={Binding ElementName=MainControl,Path=DataContext.Y}
SelectedItem={Binding ElementName=MainControl,Path=DataContext.SelectedY}
DisplayMemberPath=Name />
</controls:DataGrid.Columns>
</controls:DataGrid>
</controls:UserControl>
The idea is to set a name to the root element connected to your datacontext, then you can access to it's datacontext property easily by the path. When you are inside of a template, the datacontext is the ItemsSource objects.
Hope it will help you a little !
ComboBox items do not reflect changes made from its source
Here is what I am trying to accomplish:
I have a WPF datagrid that binding to a database table, inside the datagrid there is a combobox(group ID) column bind to one of the columns from the database table; the combobox items are from another table(a list of group ID). The problem now is when the groupd ID list is changed from other table, the combo box items does not take effect.
Can anyone help? Have been stuct for a long time.
Here is XAML code:
<DataGridTemplateColumn Header="Group ID">
<DataGridTemplateColumn.CellTemplate>
<DataTemplate>
<TextBlock Text="{Binding GroupID, Mode=OneWay}"/>
</DataTemplate>
</DataGridTemplateColumn.CellTemplate>
<DataGridTemplateColumn.CellEditingTemplate>
<DataTemplate>
<ComboBox Name="ComboBoxTeamGrpID" SelectedItem="{Binding GroupID, Mode=TwoWay}" ItemsSource="{StaticResource ResourceKey=GroupIDList}">
</ComboBox>
</DataTemplate>
</DataGridTemplateColumn.CellEditingTemplate>
</DataGridTemplateColumn>
Here is the code for GroupIDList:
public class GroupIDList : List<string>
{
public GroupIDList()
{
try
{
string tmp = ConfigurationManager.AppSettings["DataSvcAddress"];
Uri svcUri = new Uri(tmp);
JP790DBEntities context = new JP790DBEntities(svcUri);
var deviceQry = from o in context.Devices
where o.GroupID == true
select o;
DataServiceCollection<Device> cList = new DataServiceCollection<Device>(deviceQry);
for (int i = 0; i < cList.Count; i++)
{
this.Add(cList[i].ExtensionID.Trim());
}
this.Add("None");
//this.Add("1002");
//this.Add("1111");
//this.Add("2233");
//this.Add("5544");
}
catch (Exception ex)
{
string str = ex.Message;
}
}
}
Here is another problem related, can anyone help? thank you.
It is either because your GroupIdList is a List and not an ObservableCollection, or because you're binding to a StaticResource, which WPF assumes is unchanged so is only loaded once.
Change your List<string> to an ObservableCollection<string> which will automatically notify the UI when it's collection gets changed, and if that still doesn't work than change your ItemsSource from a StaticResource to a RelativeSource binding, such as
ItemsSource="{Binding
RelativeSource={RelativeSource AncestorType={x:Type DataGrid}},
Path=DataContext.GroupIdList}"
Edit
Your parent ViewModel which has your DataGrid's ItemsSource collection should look something like below. Simply add another public property for GroupIdList and have it return your list. Then use the above RelativeSource binding to access it, assuming your DataGrid's ItemsSource is bound in the form of <DataGrid ItemsSource="{Binding MyDataGridItemsSource}" ... />
public class MyViewModel
{
private ObservableCollection<MyDataObject> _myDataGridItemsSource;
public ObservableCollection<MyDataObject> MyDataGridItemsSource
{
get { return _myDataGridItemsSource; }
set
{
if (value != _myDataGridItemsSource)
{
_myObjects = value;
ReportPropertyChanged("MyDataGridItemsSource");
}
}
}
private ObservableCollection<string> _groupIdList = new GroupIdList();
public ObservableCollection<string> GroupIdList
{
get { return _groupIdList; }
}
}
WPF will not poll everytime and check if your list changed. In Order to do this, as Rachel pointed at you should do something like :
public class GroupIDList : ObseravableCollection<string>
EDIT :
Here is my suggestion :
I actually wouldn't do it the way you did. What I do is I create a View Model for the whole grid, that looks like :
public class MyGridViewModel : DependencyObject
Which I would use as data context for my grid:
DataContext = new MyGridViewModel ();
Now the implementation of MyGridViewModel will contain a list of ViewModel that represent my GridRows, which is an ObservableCollection
public ObservableCollection<RowGridViewModel> RowItemCollection { get; private set; }
I will this in my dataGrid as such :
<Grid>
<DataGrid AutoGenerateColumns="False" ItemsSource="{Binding RowItemCollection}" SelectionMode="Extended" SelectionUnit="Cell">
<DataGrid.Columns>
and All you need to do, is to fill in you RowItemColleciton with the correct data, and then bind you Columns to the correct Property in RowGridViewModel...in your case it would look like (but you have to initialize the GroupIDList :
public class RowGridViewModel: DependencyObject
{
public List<String> GroudIDList { get; set;
}
}
Let me if that help
I have a combo box that I have bound to a list that exists in my viewmodel. Now when a users makes a selection in that combo box I want a second combo box to update its content.
So, for example, combobox1 is States and combobox2 should contain only the Zipcodes of that state.
But in my case I don't have a predefined lists before hand for combobox2, I need to go fetch from a db.
Also, if needed, I could get all the potential values for combobox2 (for each combobox1 value) before hand, but I'd like to avoiding that if I can.
How do I implement in WPF and using MVVM? I'm fairly new to this whole wpf\databinding\mvvm world.
Something like the following. Note that the code is drastically simplified for the sake of example. In reality, your ViewModel would implement INotifyPropertyChanged and raise PropertyChanged events when the properties were modified.
The key though is the setter of SelectedState. Your ComboBox would bind its SelectedValue property to the ViewModel's SelectedState property. When the property changed, the ZipCodes collection gets re-loaded which another combobox would be bound to.
class MyViewModel {
public ObservableCollection<string> States {
get;
private set;
}
public ObservableCollection<string> ZipCodes {
get;
private set;
}
public string SelectedState {
get { return _selectedState; }
set {
_selectedState = value;
LoadZipCodes(_selectedState);
}
}
public string SelectedZipCode {
get;
set;
}
void LoadZipCodes(string state) {
// repopulate the ZipCodes property
}
}
Another solution. The approximate model:
class StateViewModel
{
public string StateName
{
get {...}
set {...}
}
public ObservableCollection<ZipCodeViewModel> ZipCodes
{
get {...}
set {...}
}
}
class ZipCodeViewModel
{
public string ZipCodeName
{
get {...}
set {...}
}
}
class MainViewModel
{
public ObservableCollection<StateViewModel> States
{
get {...}
set {...}
}
}
And XAML:
<ComboBox ItemsSource="{Binding Path=States}" IsSynchronizedWithCurrentItem="True">
<ComboBox.ItemTemplate>
<DataTemplate>
<Label Content="{Binding Path=StateName}"></Label>
</DataTemplate>
</ComboBox.ItemTemplate>
</ComboBox>
<ContentControl Content="{Binding Path=States}">
<ContentControl.ContentTemplate>
<DataTemplate>
<ComboBox ItemsSource="{Binding Path=ZipCodes}">
<ComboBox.ItemTemplate>
<DataTemplate>
<Label Content="{Binding Path=ZipCodeName}"></Label>
</DataTemplate>
</ComboBox.ItemTemplate>
</ComboBox>
</DataTemplate>
</ContentControl.ContentTemplate>
</ContentControl>
I have an ItemsControl with a DataTemplate that has been defined. My ItemsControl definition looks like the following:
<ItemsControl x:Name="myItemsControl" ItemsSource="{Binding}">
<ItemsControl.ItemTemplate>
<DataTemplate>
<Grid>
<CheckBox x:Name="myCheckBox" Content="{Binding Name}" />
</Grid>
</DataTemplate>
</ItemsControl.ItemTemplate>
</ItemsControl>
This is a simplified version of my DataTemplate. Regardless, when a user clicks a button on the page, I want to loop through the items in myItemsControl and determine if the CheckBox element associated with the item is checked.
How do I determine if a CheckBox is checked for a specific item within an ItemsControl?
Thank you!
Add a property to your data class and databind it, then iterate over the collection itself.
public class myDataClass
{
public string Name { get; set;}
public bool IsSomething { get; set; }
}
<CheckBox x:Name="myCheckBox" Content="{Binding Name}" IsChecked="{Binding IsChecked, Mode=TwoWay}" />
You can try something like traditional iteration:
public bool? TestMyCheckbox(string bindingName)
{
foreach (var item in myItemsControl.Items)
{
if (item.GetType() == typeof(CheckBox))
{
var checkbox = (CheckBox)item;
if (checkbox.Content.Equals(bindingName))
{
return (checkbox.IsChecked);
}
}
}
return null;
}
Additionaly (this may better fit your needs) you can look for a list of checkboxes bindings that are checked:
public IEnumerable<object> TestMyCheckboxes(ItemsControl control)
{
return from Control x in control.Items
where x.GetType().Equals(typeof(CheckBox)) && ((CheckBox)x).IsChecked == true
select ((CheckBox)x).Content;
}