I\'m used to doing things like
State.Items.Add(new ListItem { Text = \"SomeState\", Value = NumericIDofState });
Where State is a Listbox in A
See these properties of combo:
If you only want to expose a simple property in the viewmodel and handle the text for the choices in the view you can do a simple solution like this:
<ComboBox SelectedValuePath="Tag" SelectedValue="{Binding YourIntProperty, Mode=TwoWay}">
<ComboBoxItem Content="First choice" Tag="0"/>
<ComboBoxItem Content="Second choice" Tag="1"/>
<ComboBoxItem Content="Third choice" Tag="2"/>
</ComboBox>
Example with a bool property:
<ComboBox SelectedValuePath="Tag" SelectedValue="{Binding IsActive, Mode=TwoWay}">
<ComboBoxItem Content="No" Tag="False"/>
<ComboBoxItem Content="Yes" Tag="True"/>
</ComboBox>
Type-verbose alternatives (original examples)
Below are more verbose alternatives where the types are explicitly declared. Depending on your preferred style (or maybe some types that requires it), maybe it suits you better.
<ComboBox SelectedValuePath="Tag" SelectedValue="{Binding YourIntProperty, Mode=TwoWay}">
<ComboBoxItem Content="First choice">
<ComboBoxItem.Tag>
<sys:Int32>0</sys:Int32>
</ComboBoxItem.Tag>
</ComboBoxItem>
<ComboBoxItem Content="Second choice">
<ComboBoxItem.Tag>
<sys:Int32>1</sys:Int32>
</ComboBoxItem.Tag>
</ComboBoxItem>
<ComboBoxItem Content="Third choice">
<ComboBoxItem.Tag>
<sys:Int32>2</sys:Int32>
</ComboBoxItem.Tag>
</ComboBoxItem>
</ComboBox>
Example with a bool property:
<ComboBox SelectedValuePath="Tag" SelectedValue="{Binding IsActive, Mode=TwoWay}">
<ComboBoxItem Content="No">
<ComboBoxItem.Tag>
<sys:Boolean>False</sys:Boolean>
</ComboBoxItem.Tag>
</ComboBoxItem>
<ComboBoxItem Content="Yes">
<ComboBoxItem.Tag>
<sys:Boolean>True</sys:Boolean>
</ComboBoxItem.Tag>
</ComboBoxItem>
</ComboBox>
The sys namespace is declared as this:
xmlns:sys="clr-namespace:System;assembly=mscorlib"
WPF Combobox has:
SelectedValue
property. It's similar to ASP.NET ListItem
's Value
property.ListItem
's Text
property.Let's say you want your Combobox
to show a collection of the following KeyValuePair
objects:
private static readonly KeyValuePair<int, string>[] tripLengthList = {
new KeyValuePair<int, string>(0, "0"),
new KeyValuePair<int, string>(30, "30"),
new KeyValuePair<int, string>(50, "50"),
new KeyValuePair<int, string>(100, "100"),
};
You define a property in your view model returning that collection:
public KeyValuePair<int, string>[] TripLengthList
{
get
{
return tripLengthList;
}
}
Then, your XAML for the Combobox
would be:
<ComboBox
SelectedValue="{Binding FilterService.TripLengthFrom, Mode=TwoWay}"
ItemsSource="{Binding TripLengthList, Mode=OneTime}"
SelectedValuePath="Key"
DisplayMemberPath="Value" />
Where you set SelectedValuePath
and DisplayMemberPath
properties to the desired property names of the objects (Key
and Value
correspondingly) displaying by the Combobox
.
Or, if you really want to add items to Combobox
in code behind instead of using a binding, you can do it as well. For example:
<!--XAML-->
<ComboBox x:Name="ComboBoxFrom"
SelectedValue="{Binding FilterService.TripLengthFrom, Mode=TwoWay}" />
// Code behind
public partial class FilterView : UserControl
{
public FilterView()
{
this.InitializeComponent();
this.ComboBoxFrom.SelectedValuePath = "Key";
this.ComboBoxFrom.DisplayMemberPath = "Value";
this.ComboBoxFrom.Items.Add(new KeyValuePair<int, string>(0, "0"));
this.ComboBoxFrom.Items.Add(new KeyValuePair<int, string>(30, "30"));
this.ComboBoxFrom.Items.Add(new KeyValuePair<int, string>(50, "50"));
this.ComboBoxFrom.Items.Add(new KeyValuePair<int, string>(100, "100"));
}
If you skip the Value, then I think it's quite simple to add a new item into a ComboBox during runtime.
comboBox1.Items.Add("SomeText");
comboBox1.SelectedIndex = comboBox1.Items.Count - 1;
The SelectedIndex
property is set to Items.Count-1
so that the newly added item appears in the ComboBox as the selected item.