Formatting Strings in Binding

Introduction

Recently, I got a chance to do a code walk through of a WPF application in order to achieve better performance. So, during my review process, I came across the code snippet given below:

<WrapPanel>
        <TextBlock Text="{Binding Path=FirstName,Mode=OneWay}"/>
        <TextBlock Text=" "/>
        <TextBlock Text="{Binding Path=LastName,Mode=OneWay}"/>
 </WrapPanel> 

If you will closely analyze this given snippet, you will definitely get a way to optimize it. Well, I am talking about formatting the string as well as binding part.

As most of you are aware, we have a property named StringFormat since .NET 3.5 SP1. SO, why can't we use this property for our binding too. If you want to change the above code to incorporate StringFormat, then it will look something like:

<WrapPanel>
        <TextBlock>
                <TextBlock.Text>
                    <MultiBinding StringFormat="{}{0} {1}">
                        <Binding Path="FirstName" Mode="OneWay"/>
                        <Binding Path="LastName" Mode="OneWay"/>
                    </MultiBinding>
                </TextBlock.Text>
        </TextBlock>
 </WrapPanel> 

Now here, once can clearly see the double benefit of writing such code. The first benefit is, instead of using two bindings, one can be used and another benefit is instead of using three TextBlocks, only one can be used.

This may help in achieving performance especially when used as a DataTemplate of an ItemsControl with a huge number of items.

Please note that {} part at the beginning is an escape sequence, otherwise XAML parser would consider { to be the beginning of markup extension.