WPF DatagridCombobox 列不在 combobox 样式中

Question

This has been a long problem of mine, and even though there are a lot of solutions out there, none has seemed to work for me.

How do I make the DataGridComboBoxColumn display as Combobox when it is not focused? I tried using DataGridTemplateColumn and I've almost been successful in it except that when trying to identify the selected item in the Combobox , the value returns back to previous data, and honestly made it a lot harder for me to work on this compared to just using DataGridComboBoxColumn .

How can I do this without using DataGridTemplateColumn ? The DataGrid is found in a UserControl which is dynamically added to the MainWindow.

XAML

<!-- This is my preferred way-->
<DataGridComboBoxColumn Header TagType x:Name="TagTypeCombo" SelectedValueBinding="{Binding TagType}"/>

<!--This is similar to all of solutions that I've seen-->
<DataGridTemplateColumn Header="Tag Type" x:Name="ComboTemplate">
    <DataGridTemplateColumn.CellTemplate>
        <DataTemplate>
            <ComboBox Width="135" x:Name="Tagger" ItemsSource="{Binding tagType,RelativeSource={RelativeSource Mode=FindAncestor,AncestorType=UserControl}}" SelectedItem="{Binding Tags}" SelectedValuePath="TagType"/>
        </DataTemplate>
    </DataGridTemplateColumn.CellTemplate>
</DataGridTemplateColumn>

Code-Behind

public int counter;
List<Tags> tags = new List<Tags>();
public event EventHandler SaveButtonClicked;
public List<string> tagType = new List<string>() { "Modbus Coil(0x)", "Discrete Input(1x)", "Input Register(3x)", "Holding Register(4x)" };
public ModbusCard2()
{
    InitializeComponent();
}
public class Tags
{
    public int TagAddress { get; set; }
    public string TagType { get; set; }
    public string TagID { get; set; }
}
private void DeleteButton_Click(object sender, RoutedEventArgs e) => ((WrapPanel)this.Parent).Children.Remove(this);
private void Tagger_Loaded(object sender, RoutedEventArgs e)
{
    var cx = sender as ComboBox;
    cx.ItemsSource = tagType;
}
private void UserControl_Loaded(object sender, RoutedEventArgs e)
{
    for (int i = 1; i <= counter; i++)
    {
        tags.Add(new Tags() { TagAddress = 0, TagID = $"M{i}", TagType = "Discrete Input(1x)" });
    }
   DevTags.ItemsSource = tags;
}

private void SaveButton_Click(object sender, RoutedEventArgs e)
{
    SaveButtonClicked?.Invoke(sender, e);
}

private void EditButton_Click(object sender, RoutedEventArgs e) => DevTags.IsReadOnly = false;

//For the SaveButtonClicked found in MainWindow
private void SaveButtonClicked(ModbusCard2 d)
{
    foreach (var a in d.DevTags.Items.OfType<Tags>().ToList())
    {
        if (a.TagType == d.tagType[1])
        {
            a.TagID = $"M{DICount}";
            DICount++;
        }
        if (a.TagType == d.tagType[2])
        {
            a.TagID = $"R{AICount}";
            AICount++;
        }
        d.DevTags.Items.Refresh();
    }
    d.DevTags.IsReadOnly = true;
}

Answer 1

Try this with your ComboBox that's currently inside your TemplateColumn .

It adds logic in your binding to update your source trigger, while also removing your SelectedValuePath tag. I'm assuming based on your lack of a DisplayMemberPath tag that your ComboBox ItemsSource is a string collection. If this is the case the SelectedValuePath can actually wreck your bindings (I have no idea why though).

<ComboBox Width="135" x:Name="Tagger" ItemsSource="{Binding tagType,RelativeSource={RelativeSource Mode=FindAncestor,AncestorType=UserControl}}" SelectedItem="{Binding Tags, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"/>

Let me know if you still have binding update issues after, and will go from here.