CodeProject Latest postings for WPF

HOW TO ANSWER A QUESTION

Chris Maunder — Thu, 16 Jul 2009 13:09:00 GMT

Apologies for the shouting but this is important.

When answering a question please:

Read the question carefully
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar
If a question is poorly phrased then either ask for clarification, ignore it, or mark it down. Insults are not welcome
If the question is inappropriate then click the 'vote to remove message' button

Insults, slap-downs and sarcasm aren't welcome. Let's work to help developers, not make them feel stupid.

cheers,
Chris Maunder

The Code Project Co-founder
Microsoft C++ MVP

How to get an answer to your question

Chris Maunder — Thu, 16 Jul 2009 13:05:00 GMT

For those new to message boards please try to follow a few simple rules when posting your question.

Choose the correct forum for your message. Posting a VB.NET question in the C++ forum will end in tears.
Be specific! Don't ask "can someone send me the code to create an application that does 'X'. Pinpoint exactly what it is you need help with.
Keep the subject line brief, but descriptive. eg "File Serialization problem"
Keep the question as brief as possible. If you have to include code, include the smallest snippet of code you can.
Be careful when including code that you haven't made a typo. Typing mistakes can become the focal point instead of the actual question you asked.
Do not remove or empty a message if others have replied. Keep the thread intact and available for others to search and read. If your problem was answered then edit your message and add "[Solved]" to the subject line of the original post, and cast an approval vote to the one or several answers that really helped you.
If you are posting source code with your question, place it inside <pre></pre> tags. We advise you also check the "Encode "<" (and other HTML) characters when pasting" checkbox before pasting anything inside the PRE block, and make sure "Use HTML in this post" check box is checked.
Be courteous and DON'T SHOUT. Everyone here helps because they enjoy helping others, not because it's their job.
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No advertising or soliciting.
We reserve the right to move your posts to a more appropriate forum or to delete anything deemed inappropriate or illegal.

cheers,
Chris Maunder

The Code Project Co-founder

Microsoft C++ MVP

How to create and save High Score in my Tetris game in wpf c#?

Member 16286091 — Mon, 01 Jul 2024 11:03:00 GMT

I wanna know isn't save in my computer .If i run my game and score high score and then close my game.When i run it again next time there will remain my high score every time i run.

Plz tell me and thank you.

select text box lines and remove

geomeo123 — Sun, 23 Jun 2024 02:30:00 GMT

I have a textbox display that has incoming data from a serial port that I display. After 200 lines of data that has came in I want to remove 20 lines at the beginning. Here is my code:

private void TextBoxADCPDisplay_TextChanged(object sender, TextChangedEventArgs e)
{

    TextBoxADCPDisplay.SelectionStart = TextBoxADCPDisplay.Text.Length;
    TextBoxADCPDisplay.ScrollToEnd();
    if (TextBoxADCPDisplay.LineCount > 200)
    {
        TextBoxADCPDisplay.Select(0, 20);
        TextBoxADCPDisplay.SelectedText = "";
        
    }
}

I get some strange behavior. Where after I hit 200 lines I see multiple lines that are the same where they should be different, but if I manually scroll up a little and scroll back down the lines of data that are coming in display as they should. What am I doing wrong?

Custom Control Based On Combobox - Replace Part Of The Combobox

Kevin Marois — Sat, 15 Jun 2024 04:27:00 GMT

I'm looking at the deault combobox style[^]

I'm not entirely sure how to ask what I'm thinking, so please bear with me...

Is it possible to replace a part of the control? For example, if I wanted to create a custome combobox. I know in the C# file I just subclass it

public class MyComboBox : ComboBox
{
    static MyComboBox()
    {
        DefaultStyleKeyProperty.OverrideMetadata(typeof(MyComboBox),
            new FrameworkPropertyMetadata(typeof(MyComboBox)));
    }

    // Add some DP's and logic
}

But in the Generic.xaml, I seems like I would need to have ALL the default xaml from the site above - so that it looks & functions like a combobox.

Is there a way for me to provide just a new ContentSite? Can I justy define that in my Generic.xaml and somehow apply that to my combobox?

Ot do I need to copy in all the default XAML?

Thanks

In theory, theory and practice are the same. But in practice, they never are.”
If it's not broken, fix it until it is.
Everything makes sense in someone's mind.

Invoke WPF

geomeo123 — Sun, 02 Jun 2024 01:31:00 GMT

I have some code I'm trying to move to my view model. And it appears that my Invoke method does not work in it. I have the following code...

public delegate void SetTextCallBackSMT(string text);

Handing my serial port

string SMTData = SpSMT.ReadExisting();
if (SMTData.Contains("\r"))
{
    modeSMT = ModeSMT.readLineSMTData;
}
else
{

    Invoke(new SetTextCallBackSMT(SetTextSMTDisplay), SMTData.ToString());

}

And my set text method....

private void SetTextSMTDisplay(string text)
{
    this.RichTextBoxSMTDisplay.Text += text;
}

The problem I'm having is that Invoke does not exist in the current context. I've tried adding forms name space. I've tried Dispatcher.Invoke, but I can't get that to work either. Any ideas?

ICommand Wpf form load properties?

geomeo123 — Fri, 31 May 2024 00:11:00 GMT

I'm trying to update my program to WPF MVVM with Icommands to make my program look a little better and reduce the amount of event handlers, clutter etc, which I've managed to make workish. Well if I press a button in WPF my message box executes, so that's always good right? But I have some properties in my old windows form load event that I need to move over and I'm not exactly sure how I would implement that. I'm using the serialport io namespace and so I'm loading things like this at form load time:

SP.Handshake = Handshake.None;
SP.DataReceived += new SerialDataReceivedEventHandler(SP_DataReceived);

SP meaning serial port. Do I put the above in my wpf form load event and make these public so that my modelview class can see them? Or is there an alternative? My model view class inherits from my viewbasemodel so it doesn't allow inheriting from another base class. I could move them to my viewbasemodel class, but I'm not sure about that one either. I still have to make them run at form load. I have to say I'm only half understanding the modelview at the moment. The tutorials online aren't clicking just yet. But I have made it workish so that's always good.

WrapPanel / ItemsControl Problem

Kevin Marois — Thu, 30 May 2024 02:15:00 GMT

I'm trying to use a WrapPanel inside an ItemsControl. I'm following this[^].

The difference is that mine is bound to a list of objects called Backups.

Here's what I have. When I run it, I don't see any of the data.

<Border Grid.Row="1"
        CornerRadius="20"
        Margin="35"
        Padding="10"
        Background="Tan"
        BorderThickness="3"
        BorderBrush="SteelBlue">

    <ScrollViewer VerticalScrollBarVisibility="Auto"
                    Background="Teal"
                    Margin="10">

        <ItemsControl ItemsSource="{Binding Backups}">

            <ItemsControl.ItemTemplate>

                <DataTemplate>

                    <Border Background="Salmon"
                            BorderBrush="Blue"
                            BorderThickness="3">

                        <StackPanel Orientation="Vertical">

                            <Rectangle Margin="5" 
                                        Width="100" 
                                        Height="100" 
                                        Fill="Yellow"
                                        HorizontalAlignment="Center"/>
                            <TextBlock Text="THIS IS A TEST"
                                        HorizontalAlignment="Center"
                                        Margin="5"/>

                        </StackPanel>

                    </Border>

                </DataTemplate>

            </ItemsControl.ItemTemplate>

            <ItemsControl.ItemsPanel>
                <ItemsPanelTemplate>
                    <WrapPanel IsItemsHost="True"/>
                </ItemsPanelTemplate>
            </ItemsControl.ItemsPanel>

        </ItemsControl>

    </ScrollViewer>

</Border>

In theory, theory and practice are the same. But in practice, they never are.”
If it's not broken, fix it until it is.
Everything makes sense in someone's mind.

Initialize Webview2 in WPF Application work for windows user authentication

Aditi Arora 2021 — Thu, 16 May 2024 18:05:00 GMT

I am facing an exception while WebView initialize. It is working perfectly fine when i debug my code on VS 2019 but when i make an installer and install it on VM Windows 10 Machine it gives me an exception which i can get with help of Logs.
I have added UDF as well in my client machine and install Microsoft edge runtime(124.0.2478.97)

Please Suggest any one what i need to add to resolve this issue.

Code Block

MainWindow.xaml.cs
using Microsoft.Web.WebView2.Core;
using Microsoft.Web.WebView2.Wpf; 
public MainWindow()
        {
           InitializeComponent();
           InitializeAndNavigateAsync( url);
        }
  public async Task InitializeAndNavigateAsync(string url)
        {
            await InitializeWebViewAsync();
            await NavigateToUrlAsync(url);
        }

        private async Task InitializeWebViewAsync()
        {
            try
            {
                log.Debug($"WebView2 initialize start");
                await webView.EnsureCoreWebView2Async(null);
                log.Debug($"WebView2 initialize stop");
            }
            catch (Exception e)
            {
                log.Debug($"WebView2 initialization failed.{e.Message}");
                log.Debug($"WebView2 initialization failed.{e.StackTrace}");
            }

        }

        private async Task NavigateToUrlAsync(string url)
        {
            try
            {
                log.Debug($"WebView2 NavigateToUrlAsync start");
                webView.CoreWebView2.Navigate(url);
                log.Debug($"WebView2 NavigateToUrlAsync stop");
            }
            catch (Exception e)
            {
                log.Debug($"WebView2 NavigateToUrlAsync failed.{e.Message}");
                log.Debug($"WebView2 NavigateToUrlAsync failed.{e.StackTrace}");

            }

        }

Exception is :

WebView2 initialization failed.Server execution failed (Exception from HRESULT: 0x80080005 (CO_E_SERVER_EXEC_FAILURE))
2024-05-14 06:34:45.4923|DEBUG|debug|WebView2 initialization failed.   at System.Runtime.InteropServices.Marshal.ThrowExceptionForHRInternal(Int32 errorCode, IntPtr errorInfo)
   at Microsoft.Web.WebView2.Core.CoreWebView2Environment.<CreateCoreWebView2ControllerAsync>d__80.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.Web.WebView2.Wpf.WebView2.<>c__DisplayClass32_0.<<EnsureCoreWebView2Async>g__Init|0>d.MoveNext()
2024-05-14 06:34:45.4923|DEBUG|debug|WebView2 initialization failed.mscorlib

Binding Header in TabItem to child property in the ViewModel

Kenneth Haugland — Mon, 29 Apr 2024 07:57:00 GMT

I have a standard C#, WPF, and PRISM project, and I wanted to have one module per tab item. But I want to bind the header of a property in the ViewModel directly to the parent TabItem.

I tried this (among other things such as Content.DataContext.Message etc.) :

XML

<TabItem Header="{Binding DataContext.Message, RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type UserControl}}}">
                <ContentControl prism:RegionManager.RegionName="{x:Static core:RegionNames.ContentRegion}"></ContentControl>
            </TabItem>

I have a distinct feeling I have done this before, but I cannot figure it out at the moment, so any suggestions?

DataGrid Built In ViewModel Question

Kevin Marois — Mon, 08 Apr 2024 23:24:00 GMT

I'm building and populating a DataGrid in a viewmodel.

Here's what I'm making[^]

The two columns on the right, AutoAdjustment and AutoPosting, are combo boxes where the user can selecte 'Y' or 'N'. These are the only editable columns.

For my source data, I have a list of objects called ProcoessingOutputEntries, each with a list of column objects. It's basically a 'row' object with a dynamic collection of columns on it:

private List<ProcessingOutputEntryEntity> _ProcesssingOutputEntries;
public List<ProcessingOutputEntryEntity> ProcesssingOutputEntries
{
    get { return _ProcesssingOutputEntries; }
    set
    {
        if (_ProcesssingOutputEntries != value)

        {
            _ProcesssingOutputEntries = value;
            RaisePropertyChanged(nameof(ProcesssingOutputEntries));
        }
    }
}

and

public class ProcessingOutputEntryEntity : _EntityBase
{
    private List<ColumnInfoEntity> _ProcesssingOutputColumns;
    public List<ColumnInfoEntity> ProcesssingOutputColumns
    {
        get { return _ProcesssingOutputColumns; }
        set
        {
            if (_ProcesssingOutputColumns != value)
            {
                _ProcesssingOutputColumns = value;
                RaisePropertyChanged(nameof(ProcesssingOutputColumns));
            }
        }
    }
}

and

public class ColumnInfoEntity : _EntityBase
{
    private string _ColumnName;
    public string ColumnName
    {
        get { return _ColumnName; }
        set
        {
            if (_ColumnName != value)
            {
                _ColumnName = value;
                RaisePropertyChanged(nameof(ColumnName));
            }
        }
    }

    private ColumnSources _ColumnSource;
    public ColumnSources ColumnSource
    {
        get { return _ColumnSource; }
        set
        {
            if (_ColumnSource != value)
            {
                _ColumnSource = value;
                RaisePropertyChanged(nameof(ColumnSource));
            }
        }
    }

    private ColumnTypes _ColumnType;
    public ColumnTypes ColumnType
    {
        get { return _ColumnType; }
        set
        {
            if (_ColumnType != value)
            {
                _ColumnType = value;
                RaisePropertyChanged(nameof(ColumnType));
            }
        }
    }

    private int _ColumnWidth;
    public int ColumnWidth
    {
        get { return _ColumnWidth; }
        set
        {
            if (_ColumnWidth != value)
            {
                _ColumnWidth = value;
                RaisePropertyChanged(nameof(ColumnWidth));
            }
        }
    }

    private string _DisplayAs;
    public string DisplayAs
    {
        get { return _DisplayAs; }
        set
        {
            if (_DisplayAs != value)
            {
                _DisplayAs = value;
                RaisePropertyChanged(nameof(DisplayAs));
            }
        }
    }

    private int _IndexPosition;
    public int IndexPosition
    {
        get { return _IndexPosition; }
        set
        {
            if (_IndexPosition != value)
            {
                _IndexPosition = value;
                RaisePropertyChanged(nameof(IndexPosition));
            }
        }
    }

    private bool _IsUserEditable = true;
    public bool IsUserEditable
    {
        get { return _IsUserEditable; }
        set
        {
            if (_IsUserEditable != value)
            {
                _IsUserEditable = value;
                RaisePropertyChanged(nameof(IsUserEditable));
            }
        }
    }

    private object _Data;
    public object Data
    {
        get { return _Data; }
        set
        {
            if (_Data != value)
            {
                _Data = value;
                RaisePropertyChanged(nameof(Data));
            }
        }
    }

    public override string ToString()
    {
        return $"{ColumnSource} {IndexPosition} {ColumnName}";
    }
}

I handle the WindowLoaded event to create the grid in my ViewModel:

private void WindowLoadedExecuted()
{
    // At this point, the row objects don't have an Id, so create one for each row.
    _results.ProcesssingOutputEntries.ForEach(x => x.Id = Guid.NewGuid());

    // Now, add an Id column in front of all other columns
    foreach (var entry in _results.ProcesssingOutputEntries)
    {
        var col = new ColumnInfoEntity
        {
            ColumnName = "Id",
            Data = entry.Id.ToString()
        };

        entry.ProcesssingOutputColumns.Insert(0, col);
    }

    DataColumn column = null;

    // Add data table columns using the column info objects on the first processing object
    var firstEntry = _results.ProcesssingOutputEntries.FirstOrDefault();
    foreach (var col in firstEntry.ProcesssingOutputColumns)
    {
        column = new DataColumn
        {
            DataType = Type.GetType("System.String"),
            ReadOnly = false
        };
        ColumnsDataTable.Columns.Add(column);
    }

    // Get the index positions of the AutoAdjustment and AutoPosting columns, so we can make all
    // other columns read-only
    var autoAdjColIndex = -1;
    var autoPostColIndex = -1;

    var autoAdjCol = GetProcessingOutputColumn(ColumnTypes.AutoAdjustment);

    if(autoAdjCol != null)
    {
        autoAdjColIndex = firstEntry.ProcesssingOutputColumns.IndexOf(autoAdjCol);
    }

    var autoPostCol = GetProcessingOutputColumn(ColumnTypes.AutoPosting);

    if (autoPostCol != null)
    {
        autoPostColIndex = firstEntry.ProcesssingOutputColumns.IndexOf(autoPostCol);
    }

    // Get a list of column names from the data table created above
    string[] columnNames = (from dc in ColumnsDataTable.Columns.Cast()
                            select dc.ColumnName).ToArray();

    // Create styles for the cells
    var textBoxStyle = new Style();
    textBoxStyle.Setters.Add(new Setter(TextBox.TextAlignmentProperty, TextAlignment.Right));

    var comboBoxStyle = new Style();
    comboBoxStyle.Setters.Add(new EventSetter(ComboBox.SelectionChangedEvent, new SelectionChangedEventHandler(ComboSelectionChanged)));

    // Go through each column
    int index = 0;
    foreach (string columnName in columnNames)
    {
        // Create binding
        var binding = new Binding(columnName);

        // If the column is the AutoAdjustment or AutoPosting column, add combo box columns
        // These two columns will be the right most two
        if (index == autoAdjColIndex || index == autoPostColIndex)
        {
            // Add a combo box column for it
            var col = new DataGridComboBoxColumn()
            {
                Header = firstEntry.ProcesssingOutputColumns[index].ColumnName,
                ItemsSource = new List { "Y", "N" },
                Visibility = Visibility.Visible,
                TextBinding = binding,
                IsReadOnly = false,
                CellStyle = comboBoxStyle,<br />
            };
            DataGridColumns.Add(col);
        }
        else
        {
            // Otherwise, add a read-only textbox column for it
            var col = new DataGridTextColumn()
            {
                Header = firstEntry.ProcesssingOutputColumns[index].ColumnName,
                Binding = binding,
                Visibility = Visibility.Visible,
                IsReadOnly = true,
                CellStyle = textBoxStyle
            };
            DataGridColumns.Add(col);
        }

        index++;
    }

    // Hide the first column, the Id
    //DataGridColumns.FirstOrDefault().Visibility = Visibility.Hidden;

    // Load the data into the grid
    LoadData();
}

Here's how the data is loaded

private void LoadData()
{
    ColumnsDataTable.Clear();

    foreach (var processingEntry in _results.ProcesssingOutputEntries)
    {
        // Create a new row
        DataRow row = ColumnsDataTable.NewRow();
        ColumnsDataTable.Rows.Add(row);

        // Add each column's data
        var index = 0;
        foreach (var col in processingEntry.ProcesssingOutputColumns)
        {
            row[index] = col.Data;
            index++;
        }
    }
}

The ComboBox column style handles the SelectionChanged event:

var comboBoxStyle = new Style();
comboBoxStyle.Setters.Add(new EventSetter(ComboBox.SelectionChangedEvent, new SelectionChangedEventHandler(ComboSelectionChanged)));

and

private void ComboSelectionChanged(object sender, SelectionChangedEventArgs e)
{
    // Find the selected row
    var comboBox = e.Source as ComboBox;
    var dataGrid = WPFTools.GetVisualParent(comboBox);
    var dataRowView = dataGrid.SelectedItem as DataRowView;

    if(dataRowView != null)
    {
        // Get the new selection from the combo box. It will be either 'Y' or 'N'
        var newSelection = e.AddedItems[0];

        // Get the row's Id
        var rowId = dataRowView.Row[0].ToString();
    }
}

So, the question is, in this event handler, how do I set the newly selected value back to the source row? It seems like I need to get the row, then the bound object from it. But how do I know which combox fired this event?

Thanks

In theory, theory and practice are the same. But in practice, they never are.”
If it's not broken, fix it until it is.
Everything makes sense in someone's mind.

WPF .Net 6

Kevin Marois — Fri, 15 Mar 2024 02:35:00 GMT

I'm sure this is a silly question....

I'm trying to port some behaviors from .Net Framewor 4.7 to Core 6.

This no longer compiles:

public class ComboBoxWatermarkBehavior : Behavior<ComboBox>
.
.
.

because it can't find Behavior<>

From what I can see from Google results, I was missing Microsoft.Xaml.Behaviors.Wpf. I added the package but it didn't do anything.

What am I missing here???

In theory, theory and practice are the same. But in practice, they never are.”
If it's not broken, fix it until it is.
Everything makes sense in someone's mind.

DependencyProperty fires only in ViewModel.ctor

iwangoll — Sun, 25 Feb 2024 18:34:00 GMT

Hello,
I'd tried to reduce the problem.
I've this UserControl

public class TestControl : Label 
{
    public static readonly DependencyProperty dependencyPropertyTestInfo =
        DependencyProperty.Register("TestInfo", typeof(string), typeof(TestControl),
            new PropertyMetadata("", new PropertyChangedCallback(ChangeTestInfo)));

    public string TestInfo
    {
        get => (string)GetValue(dependencyPropertyTestInfo);
        set => SetValue(dependencyPropertyTestInfo, value);
    }
    private static void ChangeTestInfo(DependencyObject d, DependencyPropertyChangedEventArgs e)
    {
        var testControl = (TestControl)d;
        testControl.TestInfo = (string)e.NewValue;
    }
}

This is the essential part of MainWindow.xaml:

<StackPanel>
    <local:TestControl Content="TestControl" x:Name="tct" TestInfo="{Binding TestInfoView}"/>
    <Button Content="show TestInfo by Button-Click in xaml.cs" x:Name="BtnShow" Click="BtnShow_Click"/>
    <Button Content="set new TestInfo" Name="BtnNewTestInfo" Command="{Binding NewTestInfoCommand}"/>
</StackPanel>

Its bounded in MainWindow.xaml.cs to DataContext with this ViewModel:

public class MainWindowViewModel : BindableBase
{
    private int counter;
    private string _testInfoView;
    public string TestInfoView
    {
        get { return _testInfoView; }
        set { SetProperty(ref _testInfoView, value); }
    }
    public DelegateCommand NewTestInfoCommand { get; }
    public MainWindowViewModel()
    {
        NewTestInfoCommand = new DelegateCommand(OnNewTestInfoCommand);
        TestInfoView = "Info from ctor";
    }
    private void OnNewTestInfoCommand()
    {
        string newInfo = $"Info No. {++counter}";
        Debug.WriteLine($"{MethodBase.GetCurrentMethod().Name}: {nameof(TestInfoView)}=«{TestInfoView}» -> «{newInfo}»");
        TestInfoView = newInfo;
    }
}

I've added a "Debug.WriteLine" in MainWindow.xaml.cs

private void BtnShow_Click(object sender, RoutedEventArgs e)
{
   Debug.WriteLine($"{MethodBase.GetCurrentMethod().Name}: {nameof(tct.TestInfo)}={tct.TestInfo}");
}

After starting the app

1. I've clicked "BtnShow" this is the debug-info:
BtnShow_Click: TestInfo=Info from ctor
2. I've clicked "BtnNewTestInfo" this is the debug-info:
OnNewTestInfoCommand: TestInfoView=«Info from ctor» -> «Info No. 1»
3. I've clicked "BtnShow" this is the debug-info:
BtnShow_Click: TestInfo=Info from ctor

Now my question is: why ViewModel-Command doesn't change the content of TestControl?

Explanation of the goal:
Based on a WrapPanel I'll add in Children ToggleButton as a representation of tags in a Control named "TagPanel". By clicking the ToggleButton I can define the Tags of a given dataset record.
To define the ToggleButton I'll set in ViewModel a string property "TagDef" with comma-separated values like "red,blue,green" to get three buttons.
And by setting a string property "CheckedTag" (i.e "green,red") I'll set IsChecked of the concerned buttons.

But by setting in viewmodel, the properties aren't changed in TagPanel. Now I'm using events - what a pity.

Get Tab For Context Menu

Kevin Marois — Sat, 27 Jan 2024 05:35:00 GMT

I have a tab control, and I have a header template and style:

<!Tab Item Header Template>
<DataTemplate x:Key="CustomHeaderTemplate">

    <DockPanel LastChildFill="True">

        <TextBlock Text="{Binding FileName}"
                   VerticalAlignment="Center"
                   FontSize="14"/>

        <Button Command="{Binding DataContext.CloseTabCommand, RelativeSource={RelativeSource AncestorType={x:Type Window}}}"
                CommandParameter="{Binding}"
                VerticalAlignment="Center"
                Height="22"
                Width="22"
                Background="SteelBlue"
                Margin="3,0,0,0">

            <Path Data="M1,9 L9,1 M1,1 L9,9"
                  Stroke="White"
                  StrokeThickness="2" />

        </Button>

    </DockPanel>

</DataTemplate>

<!Tab Item Style>
<Style TargetType="TabItem">

    <Setter Property="ContextMenu">
        <Setter.Value>
            <ContextMenu DataContext="{Binding Path=PlacementTarget.DataContext, RelativeSource={RelativeSource Self}}" >

                <MenuItem Header="Close Tab"
                          Command="{Binding Source={StaticResource Proxy}, Path=Data.CloseTabCommand}"
                          CommandParameter="{Binding}"/>

                <MenuItem Header="Close All Tabs"
                          Command="{Binding Source={StaticResource Proxy}, Path=Data.CloseAllTabsCommand}"
                          CommandParameter="{Binding}"/>

                <MenuItem Header="Close All But This"
                          Command="{Binding Source={StaticResource Proxy}, Path=Data.CloseAllButThisTabCommand}"
                          CommandParameter="{Binding}"/>
            </ContextMenu>

        </Setter.Value>
    </Setter>

</Style>

The problem is that if I right-click a tab that is NOT selected, and choose one of the close options, the SELECTED tab is closed. How can I specify that correct tab item in the command?

In theory, theory and practice are the same. But in practice, they never are.”
If it's not broken, fix it until it is.
Everything makes sense in someone's mind.

INotifyDataErrorInfo Question

Kevin Marois — Wed, 03 Jan 2024 04:07:00 GMT

I have a window with bound fields that I'm validating with INotifyDataErrorInfo. There is a button on the window that opens a dialog that the user needs to complete before all of the data is truly valid.

What I'd like is to to have a validation message next to the button. But since the button is not bound, I can't really use INotifyDataErrorInfo for this.

What's the right way to do this?

In theory, theory and practice are the same. But in practice, they never are.”
If it's not broken, fix it until it is.
Everything makes sense in someone's mind.

When Are All DependencyProperties Set

Kevin Marois — Fri, 29 Dec 2023 08:12:00 GMT

I have a CustomControl with three DP's. On startup the change callbacks fire for all three, but I need to know when they have ALL fired, so I can then set up the control using their data. The Initialized gets called first, then the DP's, so I can't rely on that.

I was thinking of creating a bool flag for each, and when each are true, then go ahead and load my control using all the DP's, but I'm wondering if there's another way.

An event that fires AFTER the DP's would be nice, but I don't see one.

In theory, theory and practice are the same. But in practice, they never are.”
If it's not broken, fix it until it is.
Everything makes sense in someone's mind.

DataTemplate Problem

Kevin Marois — Tue, 05 Dec 2023 23:08:00 GMT

I have an app that displays 1 to 16 video player controls. The user can select the type of player (ie LeadTools, VLC) and the number of players to show.

Once the type and number of players is selected, I load the players into the main window's Players collection. The ActiveX player is hosted in a PlayerHostViewl, and that is added to an ObservableCollection<playerhostviewmodel> called 'Players'

Here's the main window's XAML's resources, showing the data template for the collection:

<Window.Resources>

    <DataTemplate DataType="{x:Type vms:PlayerHostViewModel}">
        <vws:PlayerHostView/>
    </DataTemplate>

</Window.Resources>

and the MainWindow's player collection:

<Border Grid.Row="1"
        Grid.Column="0"
        BorderThickness="1"
        BorderBrush="SteelBlue"
        Margin="5,0,0,5">

    <ItemsControl ItemsSource="{Binding Players}"
                    Margin="2">

        <ItemsControl.ItemsPanel>
            <ItemsPanelTemplate>
                <UniformGrid IsItemsHost="True"
                                Margin="2"/>
            </ItemsPanelTemplate>
        </ItemsControl.ItemsPanel>

    </ItemsControl>

</Border>

The MainWindowViewModel's LoadPlayers method:

private void LoadPlayers()
{
    // If a player type and count are selected...
    if (SelectedPlayerInfo != null && SelectedPlayerCount > -1)
    {
        // For each player to add...
        for (int i = 0; i < SelectedPlayerCount + 1; i++)
        {
            // Create the player ActiveX control
            var playerAssembly = (IPlayer)Activator.CreateInstance(SelectedPlayerInfo.PlayerType);

            // Create the player host
            var player = new PlayerHostViewModel(playerAssembly, $"Player {i + 1}", LiveStream, DVRStream);

            // Add the player host to the Players list
            Players.Add(player);
        }
    }
}

Here's the PlayerHost CTORs

public PlayerHostViewModel()
{
}
public PlayerHostViewModel(IPlayer player, string playerName, string liveStream, string dvrStream)
{
    Player = player;
    PlayerName = playerName;
    LiveStream = LiveStream;
    DVRStream = dvrStream;  
}

The problem is that the PlayerHost paramterized CTOR fires when this line executes, as it should:

var player = new PlayerHostViewModel(playerAssembly, $"Player {i + 1}", LiveStream, DVRStream);

but then the default CTOR fires when this line executes, resetting all the properties the previous CTOR initialed

// Add the player host to the Players list
Players.Add(player);

I've used DataTemplates in plenty of other apps. I don't understand what's different this time. Anyone see what's wrong?

In theory, theory and practice are the same. But in practice, they never are.”
If it's not broken, fix it until it is.
Everything makes sense in someone's mind.

DataGrid Event Not Firing

Kevin Marois — Fri, 01 Dec 2023 00:11:00 GMT

I have a sample app with a AddingNewItem command for a DataGrid, but I can't get it to fire.

<i:Interaction.Triggers>
    <i:EventTrigger EventName="AddingNewItem">
        <i:InvokeCommandAction Command="{Binding DataContext.NewItemAddedCommand, 
            RelativeSource={
                RelativeSource FindAncestor, AncestorType=Window}}"/>
    </i:EventTrigger>
</i:Interaction.Triggers>

There are no binding errors or other problems. It just doesn't fire. The Setter for the command do fire.

My sample project is here [^] . Does anyone see what's wrong?

In theory, theory and practice are the same. But in practice, they never are.”
If it's not broken, fix it until it is.
Everything makes sense in someone's mind.

DataGrid Exception

Kevin Marois — Tue, 28 Nov 2023 22:36:00 GMT

I have a DataGrid that allows users to define CSV file columns for a UI I'm creating. It's bound to an ObservableCollection<columninfoentity>. I have CanUserAddRows = true. Apparantly setting this to True exposes some strange bug.

The grid's first column has a button:

<DataGrid Grid.Row="2"
          Grid.Column="0"
          ItemsSource="{Binding ColumnInfos}"
          HorizontalGridLinesBrush="LightGray"
          VerticalGridLinesBrush="LightGray"
          AutoGenerateColumns="False"
          CanUserAddRows="True"
          CanUserDeleteRows="True"
          CanUserReorderColumns="False"
          CanUserResizeColumns="False"
          CanUserSortColumns="False"
          BorderBrush="SteelBlue"
          BorderThickness="1"
          HeadersVisibility="Column"
          HorizontalScrollBarVisibility="Auto"
          VerticalScrollBarVisibility="Auto"
          VerticalAlignment="Stretch"
          Margin="5,0,5,5">

    <DataGrid.Resources>
        <local:BindingProxy x:Key="proxy" Data="{Binding IsColumnWidthVisibile}"/>
    </DataGrid.Resources>

    <DataGrid.Columns>

        <DataGridTemplateColumn>
            <DataGridTemplateColumn.CellTemplate>
                <DataTemplate>
                    <Button Command="{Binding DeleteColumnCommand, RelativeSource={RelativeSource FindAncestor,
                                                                    AncestorLevel=1, AncestorType={x:Type Window}}}"
                            CommandParameter="{Binding}"
                            Margin="2"
                            Height="18"
                            Width="18"/>
                </DataTemplate>
            </DataGridTemplateColumn.CellTemplate>
        </DataGridTemplateColumn>

        <DataGridTextColumn Header="Column Name"
                            Binding="{Binding ColumnName}"
                            Width="*"/>

        <DataGridTextColumn Header="Width"
                            Binding="{Binding ColumnWidth}"
                            Width="65"
                            Visibility="{Binding Data, Converter={StaticResource boolToVisibilityConverter}, Source={StaticResource proxy}}"/>

    </DataGrid.Columns>

</DataGrid>

When I enable CanUserAddRows it and run the app I get

System.InvalidCastException: 'Unable to cast object of type 'MS.Internal.NamedObject' to type 'WPFDataGrid.ColumnInfoEntity'.'

Strangly, the exception is thrown in the RelayCommand's CanExecute.

If I comment out the delete button everything works fine.

I created a sample project[^] to demonstrate this.

I don't understand what the error means, or why I'm getting it. Any help would be great.

In theory, theory and practice are the same. But in practice, they never are.”
If it's not broken, fix it until it is.
Everything makes sense in someone's mind.

Custom Control Style Question Revisited

Kevin Marois — Mon, 30 Oct 2023 19:14:00 GMT

I've asked about this already, but I'm not really getting it. I'm asking this again with more detail in the hopes that it'll make more sense.

Lets say I develop a custom control that have a TextBlock over a TextBox[^]. I have defind colors for Normal and Mouse Over

Here's the XAML for my control. It's pretty simple:

<pre><ResourceDictionary xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
                    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
                    xmlns:local="clr-namespace:MyTextBoxEx">

<pre>
<SolidColorBrush x:Key="CaptionNormalColor" Color="Green"/>
<SolidColorBrush x:Key="CaptionMouseOverColor" Color="Purple"/>

<SolidColorBrush x:Key="TextNormalColor" Color="Red"/>
<SolidColorBrush x:Key="TextMouseOverColor" Color="Blue"/>

<Style TargetType="{x:Type local:TextBoxEx}">

    <Setter Property="Padding" Value="1"/>

    <Setter Property="Template">

        <Setter.Value>

            <ControlTemplate TargetType="{x:Type local:TextBoxEx}">

                <StackPanel Orientation="Vertical">

                    <Border Padding="{Binding Padding, RelativeSource={RelativeSource TemplatedParent}}"
                            Margin="{Binding Margin, RelativeSource={RelativeSource TemplatedParent}}"
                            Background="{TemplateBinding Background}"
                            BorderBrush="{TemplateBinding BorderBrush}"
                            BorderThickness="{TemplateBinding BorderThickness}">

                        <StackPanel Orientation="Vertical">

                            <TextBlock x:Name="caption"
                                       Foreground="{StaticResource CaptionNormalColor}"
                                       Text="{TemplateBinding Caption}"/>

                            <TextBox x:Name="text"
                                     Foreground="{StaticResource TextNormalColor}"
                                     Text="{TemplateBinding Text}"/>

                        </StackPanel>

                    </Border>

                </StackPanel>

                <ControlTemplate.Triggers>

                    <Trigger Property="IsMouseOver" Value="true">
                        <Setter TargetName="caption" Property="TextElement.Foreground" Value="{StaticResource CaptionMouseOverColor}"/>
                        <Setter TargetName="caption" Property="TextElement.FontWeight" Value="Bold"/>

                        <Setter TargetName="text" Property="TextElement.Foreground" Value="{StaticResource TextMouseOverColor}"/>
                        <Setter TargetName="text" Property="TextElement.FontStyle" Value="Italic"/>
                    </Trigger>

                </ControlTemplate.Triggers>

            </ControlTemplate>

        </Setter.Value>

    </Setter>

</Style>

Here's the question. I have assigned colors for normal, and for the Mouse Over triggers. Assume this control was in a compiled assembly, and I gave it to you, how would you go about overwriting the theme colors, or theming it the way you wanted?

When you buy a third party control, and want apply your theme to it, how do the controls inside get their colors set? In my case, the triggers are set to a specifically named brush. Just knowing the brush names wouldn't help you overwrite the theme colors, would it?

In theory, theory and practice are the same. But in practice, they never are.”
If it's not broken, fix it until it is.
Everything makes sense in someone's mind.