Hi

When working with WPF I always found myself thinking how to handle Data formatting when a WPF control was bound to it. Let’s look at the following example of a window with a TextBlock that displays a DateTime:

   1: <Window x:Class="BindingFormat.Window1"

   2:     xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"

   3:     xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"

   4:     Title="Window1" Height="300" Width="300">

   5:     <Grid>

   6:         <TextBlock Text="{Binding}"></TextBlock>

   7:     </Grid>

   8: </Window>

This article was written by Alan Mendelevich

The Problem

Creating a shape with bullets on the joints of it’s segments sounds like a really trivial task at a first glance. Just plaster some bullets on top of the shape. And it is really something like this until you decide you want to have transparent outlined bullets or opaque bullets with transparent outline around them. Like the ones in this picture:

This article was written by Alan Mendelevich

Hi

Recently I’ve been working on a set of custom WPF controls.

There are numerous good books and articles about WPF in general and some basic information on custom control development but I have yet to find a good article (or book) with in-depth coverage of custom control development in general and design-time related issues in particular.

Hi

Here is a problem that one of my colleagues who is just starting to use WPF got himself into. He was working on an application that displays items using an ItemsControl and uses a DataTemplate. Inside the DataTemplate he used an Image. Here is the Xaml code:

   1: <Window.Resources>

   2:         <Image Source="Creek.jpg" x:Key="IMG"></Image>

   3:     </Window.Resources>

   4:     <Grid>

   5:         <ItemsControl ItemsSource="{Binding}">

   6:             <ItemsControl.ItemTemplate>

   7:                 <DataTemplate>

   8:                     <Border BorderThickness="2" BorderBrush="Black" 

   9:                             CornerRadius="3" MinHeight="10">

  10:                         <ContentControl Content="{StaticResource IMG}"/>

  11:                     </Border>

  12:                 </DataTemplate>

  13:             </ItemsControl.ItemTemplate>

  14:         </ItemsControl>

  15:     </Grid>

This is a much simpler example, but the principal is the same.

Can you see what was he doing wrong?

Hi

A while ago Shahar wrote an article about whether WPF Data Binding is Thread safe. Shahar’s findings were that Even if you change a property from a different thread the PropertyChanged event will be called on the UI Thread making Binding Thread Safe.

I have created a Window with 2 TextBlocks, one of them is binded to a Dependency Property and the other is binded to a regular property:

The Window:

   1: <StackPanel>

   2:     <TextBlock Text="{Binding DpTxt}" Width="100" Margin="5"></TextBlock>

   3:     <TextBlock Text="{Binding Txt}" Width="100" Margin="5"></TextBlock>

   4:     <Button Content="Change Text" Margin="5" Click="Button_Click"></Button>

   5: </StackPanel>

Hi

Where do you locate your convertors? do you put them in the Window.Resources section? or in the UserControl they are being used for? Neither of these options is good. You should put it in the App.Xaml file and here is why:

Lets look at the following example:

Here is our Window:

   1: <Window x:Class="ConvertorLocation.Window1"

   2:     xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"

   3:     xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"

   4:         xmlns:my="clr-namespace:ConvertorLocation"

   5:     Title="Window1" Height="300" Width="300">

   6:     <Grid>

   7:         <ItemsControl ItemsSource="{Binding}">

   8:             <ItemsControl.ItemTemplate>

   9:                 <DataTemplate>

  10:                     <my:UserControl1></my:UserControl1>

  11:                 </DataTemplate>

  12:             </ItemsControl.ItemTemplate>

  13:         </ItemsControl>

  14:     </Grid>    

  15: </Window>

Hi

While working on a complex UI application in WPF I noticed that because I was using DataTemplates both the Xaml and the Code Behind got very messy, that is because if you need to implement some events in the code behind you basically “mix” code from the template and code from the Window, plus you cannot access the elements in the template from the code behind.

Let’s look at the following example:

Hi

Yesterday I was trying to create a control with a partially transparent background,. I am writing this because what I thought was so straight forward, was not.

Here is a simple example:

   1: <Grid>

   2:    <Button Height="23" Margin="94,103,109,0" Name="button1" 

   3:            VerticalAlignment="Top">Button</Button>

   4:    <Border Margin="57,61,21,101" Name="border1" 

   5:            Background="blue" />

   6: </Grid>

When we run this example we will get the following:

Hi.

As the Headline says, I will show you how to make a Drag and Drop / Move Content control. for this example I will use a canvas and an Image. But you can easily make it more generic by using a Content Control instead of the image.

It is actually very simple, let’s start with the Xaml Code.

   1: <Canvas Grid.Row="1" Grid.Column="1" Grid.RowSpan="2" HorizontalAlignment="Stretch" 

   2:         VerticalAlignment="Stretch" x:Name="ImageHolder" >

   3:     <Image Canvas.Left="0" MouseWheel="Img_MouseWheel" MouseMove="Img_MouseMove" 

   4:            MouseDown="Img_MouseDown" MouseUp="Img_MouseUp" Panel.ZIndex="0" 

   5:            Cursor="Hand" Canvas.Top="0" Height="150" Width="150" Source="sketch.jpg" 

   6:            x:Name="Img">

   7:     </Image>

   8: </Canvas>

Implementing Drag and Move

to implement the drag and move we will need to use the following events:

• MouseDown
• MouseMove
• MouseUp

MouseDown event

Hi

In my latest article I discussed Scrolling and Binding to large collections in WPF. We saw some disturbing behavior when binding a large collection to an ItemsControl. After Further Examination I found out very interesting things regarding that matter.

Memory Consumption

We saw that the application used about 500MB of Ram. Lets look at the code again: