Develop Reference

Set combobox Item in code Behind UWP

I have seen how to select the item from the index by code behind, but how can i select it from code behind knowing the string of the item?
combobox code xaml:
<ComboBox x:Name="ComboBoxOne" VerticalAlignment="Center" HorizontalAlignment="Center" Height="40" Width="200">
<ComboBoxItem Content="blue"/>
<ComboBoxItem Content="red"/>
<ComboBoxItem Content="green"/>
</ComboBox>
combobox code behind:
ComboBoxOne.SelectedIndex = 1;
But how to select the item knowing for example green? Is possible?
I tried with ComboBoxOne.PlaceholderText
ComboBoxOne.PlaceholderText="green"
But then I can not use the selecteditem.
Thanks in advance!

First you need to get the Items of the ComboBox as a List to find the Index of the item that you want to select by string. Since this will be a List<String> you can do something like below.
List<String> lstItems = ComboBoxOne.Items
.Cast<ComboBoxItem>()
.Select(item => item.Content.ToString())
.ToList();
and then you can get the index using Linq and assign it to Selected Index. Like below.
ComboBoxOne.SelectedIndex = lstItems.FindIndex(a => a.Equals("green"));
Good Luck.

Datagrid ComboBox binding two values

I have a combobox which is populated from a list of names which were obtained from selecting from an Observable collection. However, associated with those names is an ID also in that Observable collection. The goal is when the user selects a new name (Say changes "John" to "Jill") I will be able to obtain the ID, not just the name. The only way I can think of doing this is storing the ID also in the combobox somehow. But I don't know how to do that with binding.
<DataGridTemplateColumn Header="Name ">
<DataGridTemplateColumn.CellTemplate>
<DataTemplate>
<ComboBox x:Name="namescombo" ItemsSource="{Binding RelativeSource={RelativeSource AncestorType={x:Type DataGrid}}, Path=DataContext.Names}"
SelectedItem="{Binding Name, UpdateSourceTrigger=PropertyChanged}" FontSize="12" Background="White" FontFamily="Cambria" BorderBrush="White" BorderThickness="0"/>
</DataTemplate>
</DataGridTemplateColumn.CellTemplate>
</DataGridTemplateColumn>
C#
ObservableCollection<Name> Names = new ObservableCollection<Name>();
Name twofields = new Name();
var NamesQuery =
from p in dataEntities.Names
select new { p.Name, p.Id };
foreach (var p in NamesQuery)
{
Names.Add(new Name
{
ID = p.Id,
Name = p.Name
});
}
Names = Names.Select(p => p.Name).Distinct().ToList();

A ComboBox contains properties for both the DisplayMemberPath and the SelectedValuePath, so you could use it to tell the ComboBox to identify items by the "Id" property, but display the "Name" property to the user.
For example,
<DataGridTemplateColumn Header="Name ">
<DataGridTemplateColumn.CellTemplate>
<DataTemplate>
<ComboBox
ItemsSource="{Binding RelativeSource={RelativeSource AncestorType={x:Type DataGrid}}, Path=DataContext.Names}"
DisplayMemberPath="Name"
SelectedValuePath="Id"
SelectedValue="{Binding SelectedId}" />
</DataTemplate>
</DataGridTemplateColumn.CellTemplate>
</DataGridTemplateColumn>
I would recommend using SelectedValue over SelectedItem because WPF compares SelectedItem by .Equals() which defaults to comparing items by reference, and if your SelectedItem is not the exact same reference as the item in your ItemsSource, it won't get selected.
For example, SelectedItem = new Person(1, "Test"); would probably not set the selected item correctly, while SelectedItem = ItemsSource[0] would since it refers to an item that exists in the ItemsSource.
Also, it frequently makes more sense to store just the Id of the selected item on a row instead of the entire object :)

You can bind directly to Name object collection and set DisplayMemberPath to Name property so that strings are shown on GUI but in essence you have complete object binded to comboBox.
This way you can bind SelectedItem to Name object and can access Id and Name property.
<ComboBox ItemsSource="{Binding Names}" // Collection of name objects.
DisplayMemberPath="Name"
SelectedItem="{Binding SelectedNameObject}"/> // Object of type Name.

Getting Text from ComboBox in WPF

I have a ComboBox in WPF and I cant access its selected item text.
I have tried
cbItem.Text;
cbItem.SelectedItem.ToString();
XAML:
<ComboBox Name="cbItem" SelectedValuePath="ITEM_ID">
<ComboBox.ItemTemplate>
<DataTemplate>
<TextBlock Text="{Binding ITEM_NAME}" />
</DataTemplate>
</ComboBox.ItemTemplate>
</ComboBox>

Do ITEM_ID and ITEM_NAME come from an object?
String textComboBox = ((ITEMCLASS)cbItem.SelectedItem).ITEM_NAME.ToString();

Try
cbItem.SelectedValue.ToString()
This will work only if combobox values are same as the combobox text
EDIT:
Solution 1
You have to get access to the ComboBox's TextBox:
var str = (TextBox)cbItem.Template.FindName("PART_EditableTextBox", cbItem);
Then you can access the SelectedText property of that TextBox:
var selectedText = str.SelectedText; // This will give you text of selected item
Solution 2
ComboBoxItem typeItem = (ComboBoxItem)cbItem.SelectedItem;
string value = typeItem.Content.ToString();// This will give you text of selected item

Try this
<ComboBox Name="cbItem" SelectedValuePath="ITEM_ID">
<ComboBox.ItemTemplate>
<DataTemplate>
<TextBlock Name="txtblck" Text="{Binding ITEM_NAME}" />
</DataTemplate>
</ComboBox.ItemTemplate>
TextBox str = (TextBox)cbItem.FindName("txtblck");
string text = str.Text;

WPF Unable to set Selected Item of a Combo box

I have a non-bound Combobox and I want to set its value at run time. I tried a lot but cannot achieve it. Here's the code :
<ComboBox Background="#FFB7B39D" Grid.Row="1" Height="23"
HorizontalAlignment="Right" Margin="0,26,136,0"
Name="cboWellDiameter" VerticalAlignment="Top" Width="120">
<ComboBoxItem Content="meter" IsSelected="True" />
<ComboBoxItem Content="centimeter" />
</ComboBox>
In code, I am trying with :
//VALUE of sp.wellborediameterField_unit is centimeter
// Gives -1
int index = cboWellDiameter.Items.IndexOf(sp.wellborediameterField_unit);
Console.WriteLine("Index of well bore dia unit = " + index.ToString());
cboWellDiameter.SelectedIndex = index;
// cboWellDiameter.SelectedItem = sp.wellborediameterField_unit;
// cboWellDiameter.SelectedValue = sp.wellborediameterField_unit;
SelectedItem & selectedValue has no impact. Why its not even able to find in Items ? How do I set it ?
Please help me, have several such non-bound and binded combos to set programmatically.

The issue is that your items are ComboBoxItems, not strings. So you have two options: one, use strings as the combo-box items (this allows you to set SelectedItem / SelectedValue = "meter" or "centimeter"):
<ComboBox xmlns:clr="clr-namespace:System;assembly=mscorlib">
<clr:String>meter</clr:String>
<clr:String>centimeter</clr:String>
</ComboBox>
or two, set the SelectedItem by searching for the appropriate ComboBoxItem:
cboWellDiameter.SelectedItem = cboWellDiameter.Items.OfType<ComboBoxItem>()
.FirstOrDefault(item => item.Content as string == cosp.wellborediameterField_unit);

Bind an ObservableCollection to a ComboBox in WPF

I'm using Entity Framework as my database source and need to convert a Linq query "var" type to an ObservableCollection. I then need to bind the ObservableCollection to a ComboBox on WPF form; binding to ItemsSource, DisplayMemeberPath, SelectedValuePath and SelectedValue.
Here is Code:
using (PulseContext pc = new PulseContext())
{
var maritalcodes = from m in pc.CodeMaster
where m.Type == "16"
select new { m.Code, m.Description };
prop.ClientData.Options = new ObservableCollection<object>(maritalcodes);
}
Problem is the ComboBox is showing this as "{ Code = ????, Description = ???? }" instead of bind to code for value and description for display. What do I have to do to get the ComboBox to bind to the individual elements?

You need to set SelectedValuePath and DisplayMemberPath like this:
prop.ClientData.Options = new ObservableCollection<object>(maritalcodes);
prop.ClientData.Options.SelectedValuePath = "Code";
prop.ClientData.Options.DisplayMemberPath = "Description";
Or you can set them in xaml like this:
<ComboBox ItemsSource="{Binding Path=maritalcodes}"
SelectedValuePath="Code"
DisplayMemberPath="Description" />

<ComboBox ItemsSource="{Binding Path=maritalcodes}"
SelectedValuePath="Code"
DisplayMemberPath="Description"
SelectedValue="{Binding Path=Code}"/>
I hope this will help.