How do I work on combobox inside a datagrid in WPF?

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I have a combobox that has data that is populated from Database. I can use the binding of combobox into text box like :

But when the same is applied as the 1st column, the combobox feature is not firing, it behaves just as another textbox

What I have tried:

<DataGridTemplateColumn Header="ProductName" ClipboardContentBinding="{Binding ProductName}">
                            <DataGridTemplateColumn.CellTemplate >
                                <DataTemplate >
                                 <TextBox Text="{Binding  ProductName, NotifyOnTargetUpdated=True,  UpdateSourceTrigger=PropertyChanged}" >                                   </TextBox>
                                   
                                </DataTemplate>
                            </DataGridTemplateColumn.CellTemplate>
                            <DataGridTemplateColumn.CellEditingTemplate>
                                <DataTemplate>
                                    <ComboBox IsEditable="True" Name="cmbProductName"  ItemsSource="{StaticResource ProductNames}" SelectedItem="{Binding ProductName ,  Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}" IsDropDownOpen="False" >

                                    </ComboBox>
                                </DataTemplate>
                            </DataGridTemplateColumn.CellEditingTemplate>
                        </DataGridTemplateColumn>

Posted 6-Sep-18 2:54am

Member 13796002

Updated 6-Sep-18 12:35pm

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Graeme_Grant · Answer 1 · 2018-09-06T12:35:00

Here is a working example for you...

First, a base class for INotifyPropertyChanged for DataBinding notifications:

C#

public abstract class ObservableBase : INotifyPropertyChanged
{
    public void Set<TValue>(ref TValue field, TValue newValue,
                            [CallerMemberName] string propertyName = "")
    {
        if (EqualityComparer<TValue>.Default.Equals(field, default(TValue))
            || !field.Equals(newValue))
        {
            field = newValue;
            PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
        }
    }

    public event PropertyChangedEventHandler PropertyChanged;
}

Next we need a data model to hold each row for editing:

C#

public class PersonModel : ObservableBase
{
    private string name;
    public string Name
    {
        get { return name; }
        set { Set(ref name, value); }
    }

    private int age;
    public int Age
    {
        get { return age; }
        set { Set(ref age, value); }
    }

    private int income;
    public int Income
        {
        get { return income; }
        set { Set(ref income, value); }
    }
}

Next we need to have a ViewModel to link our data to the view:

C#

class MainViewModel
{
    public MainViewModel()
    {
        Mock();
    }

    private void Mock()
    {
        for (int i = 20; i < 120; i++)
        {
            AgeRange.Add(i);
        }

        for (int i = 0; i < 100; i++)
        {
            IncomeRange.Add(10000 + 10 * i);
        }

        for (int i = 0; i < 100; i++)
        {
            People.Add(new PersonModel
            {
                Name = $"Person {i}",
                Age = AgeRange[rand.Next(0, AgeRange.Count - 1)],
                Income = IncomeRange[rand.Next(0, IncomeRange.Count - 1)]
            });
        }
    }

    private Random rand = new Random();

    public ObservableCollection<PersonModel> People { get; }
        = new ObservableCollection<PersonModel>();

    public ObservableCollection<int> AgeRange { get; }
        = new ObservableCollection<int>();

    public ObservableCollection<int> IncomeRange { get; }
        = new ObservableCollection<int>();
}

Now we can do the View:

XML

<Window x:Class="DataGridColumnComboBox.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:local="clr-namespace:DataGridColumnComboBox"
        mc:Ignorable="d"
        Title="MainWindow" Height="450" Width="800">
    <Window.DataContext>
        <local:MainViewModel/>
    </Window.DataContext>
    <DataGrid ItemsSource="{Binding People}"
              AutoGenerateColumns="False"
              GridLinesVisibility="None" Margin="10">
        <DataGrid.Columns>
            <DataGridTextColumn Header="Name" Binding="{Binding Name}" Width="200"/>

            <DataGridComboBoxColumn Header="Age" Width="75"
                                    SelectedItemBinding="{Binding Age}">
                <DataGridComboBoxColumn.ElementStyle>
                    <Style TargetType="ComboBox">
                        <Setter Property="ItemsSource"
                                Value="{Binding RelativeSource={RelativeSource
                                    FindAncestor, 
                                    AncestorType={x:Type Window}},
                                    Path=DataContext.AgeRange}"/>
                    </Style>
                </DataGridComboBoxColumn.ElementStyle>
                <DataGridComboBoxColumn.EditingElementStyle>
                    <Style TargetType="ComboBox">
                        <Setter Property="ItemsSource"
                                Value="{Binding RelativeSource={RelativeSource
                                    FindAncestor,
                                    AncestorType={x:Type Window}},
                                    Path=DataContext.AgeRange}"/>
                    </Style>
                </DataGridComboBoxColumn.EditingElementStyle>
            </DataGridComboBoxColumn>

            <DataGridComboBoxColumn Header="Income" Width="150"
                                    SelectedItemBinding="{Binding Income}">
                <DataGridComboBoxColumn.ElementStyle>
                    <Style TargetType="ComboBox">
                        <Setter Property="ItemsSource"
                                Value="{Binding RelativeSource={RelativeSource
                                    FindAncestor, 
                                    AncestorType={x:Type Window}},
                                    Path=DataContext.IncomeRange}"/>
                    </Style>
                </DataGridComboBoxColumn.ElementStyle>
                <DataGridComboBoxColumn.EditingElementStyle>
                    <Style TargetType="ComboBox">
                        <Setter Property="ItemsSource"
                                Value="{Binding RelativeSource={RelativeSource
                                    FindAncestor,
                                    AncestorType={x:Type Window}},
                                    Path=DataContext.IncomeRange}"/>
                    </Style>
                </DataGridComboBoxColumn.EditingElementStyle>
            </DataGridComboBoxColumn>
        </DataGrid.Columns>
    </DataGrid>
</Window>

The view is quite verbose. You can simplify the code and reduce the typos by using styles:

XML

<DataGrid ItemsSource="{Binding People}"
          AutoGenerateColumns="False"
          GridLinesVisibility="None" Margin="10">
    <DataGrid.Resources>
        <Style TargetType="ComboBox" x:Key="AgeRangeStyle">
            <Setter Property="ItemsSource"
                    Value="{Binding RelativeSource={RelativeSource
                                FindAncestor, 
                                AncestorType={x:Type Window}},
                                Path=DataContext.AgeRange}"/>
        </Style>
        <Style TargetType="ComboBox" x:Key="IncomeRangeStyle">
            <Setter Property="ItemsSource"
                    Value="{Binding RelativeSource={RelativeSource
                                FindAncestor, 
                                AncestorType={x:Type Window}},
                                Path=DataContext.IncomeRange}"/>
        </Style>
    </DataGrid.Resources>
    <DataGrid.Columns>
        <DataGridTextColumn Header="Name" Binding="{Binding Name}" Width="200"/>

        <DataGridComboBoxColumn Header="Age" Width="75"
                                SelectedItemBinding="{Binding Age}"
                                ElementStyle="{StaticResource AgeRangeStyle}"
                                EditingElementStyle="{StaticResource AgeRangeStyle}"/>

        <DataGridComboBoxColumn Header="Income" Width="75"
                                SelectedItemBinding="{Binding Income}"
                                ElementStyle="{StaticResource IncomeRangeStyle}"
                                EditingElementStyle="{StaticResource
                                                                  IncomeRangeStyle}"/>

    </DataGrid.Columns>
</DataGrid>

Enjoy!

UPDATE: Changed first column to use a ComboBox editor... see OP comments below.

MainViewModel:

C#

class MainViewModel
{
    public MainViewModel()
    {
        Mock();
    }

    private void Mock()
    {
        for (int i = 20; i < 120; i++)
        {
            AgeRange.Add(i);
        }

        for (int i = 0; i < 100; i++)
        {
            IncomeRange.Add(10000 + 10 * i);
        }

        for (int i = 0; i < 100; i++)
        {
            People.Add(new PersonModel
            {
                Name = $"Person {i}",
                Age = AgeRange[rand.Next(0, AgeRange.Count - 1)],
                Income = IncomeRange[rand.Next(0, IncomeRange.Count - 1)]
            });
        }

        Names = new ObservableCollection<string>(People.Select(x => x.Name));
    }

    private Random rand = new Random();

    public ObservableCollection<PersonModel> People { get; }
        = new ObservableCollection<PersonModel>();

    public ObservableCollection<int> AgeRange { get; }
        = new ObservableCollection<int>();

    public ObservableCollection<int> IncomeRange { get; }
        = new ObservableCollection<int>();

    public ObservableCollection<string> Names { get; private set; }
}

And the View's DataGrid:

XML

<DataGrid ItemsSource="{Binding People}"
          AutoGenerateColumns="False"
          GridLinesVisibility="None" Margin="10">
    <DataGrid.Resources>
        <Style TargetType="ComboBox" x:Key="NamesStyle">
            <Setter Property="ItemsSource"
                    Value="{Binding RelativeSource={RelativeSource
                                FindAncestor, 
                                AncestorType={x:Type Window}},
                                Path=DataContext.Names}"/>
        </Style>
        <Style TargetType="ComboBox" x:Key="AgeRangeStyle">
            <Setter Property="ItemsSource"
                    Value="{Binding RelativeSource={RelativeSource
                                FindAncestor, 
                                AncestorType={x:Type Window}},
                                Path=DataContext.AgeRange}"/>
        </Style>
        <Style TargetType="ComboBox" x:Key="IncomeRangeStyle">
            <Setter Property="ItemsSource"
                    Value="{Binding RelativeSource={RelativeSource
                                FindAncestor, 
                                AncestorType={x:Type Window}},
                                Path=DataContext.IncomeRange}"/>
        </Style>
    </DataGrid.Resources>
    <DataGrid.Columns>
        <!--<DataGridTextColumn Header="Name" Binding="{Binding Name}" Width="200"/>-->

        <DataGridComboBoxColumn Header="Name" Width="75"
                                SelectedItemBinding="{Binding Name}"
                                ElementStyle="{StaticResource NamesStyle}"
                                EditingElementStyle="{StaticResource NamesStyle}"/>

        <DataGridComboBoxColumn Header="Age" Width="75"
                                SelectedItemBinding="{Binding Age}"
                                ElementStyle="{StaticResource AgeRangeStyle}"
                                EditingElementStyle="{StaticResource AgeRangeStyle}"/>

        <DataGridComboBoxColumn Header="Income" Width="75"
                                SelectedItemBinding="{Binding Income}"
                                ElementStyle="{StaticResource IncomeRangeStyle}"
                                EditingElementStyle="{StaticResource IncomeRangeStyle}"/>

    </DataGrid.Columns>
</DataGrid>

ComboBox selection works fine for the first column... Enjoy!