What does {Binding Path=.} mean in a WPF binding?
I see some people use it, but couldn't find any explanation.
Are there any other special symbols in binding syntax (other than {Binding /})?
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2 Answers
I found this WPF Binding CheatSheet a few months back and find it very useful, especially for anyone learning WPF. There are some spelling mistakes within it, but it is still quite good.
Here is a small excerpt (which is supposed to have tabular formatting):
| Basic Binding | |
|---|---|
| {Binding} | Bind to current DataContext. |
| {Binding Name} | Bind to the “Name” property of the current DataContext. |
| {Binding Name.Length} | Bind to the Length property of the object in the Name property of the current DataContext. |
| {Binding ElementName=SomeTextBox, Path=Text} | Bind to the “Text” property of the element XAML element with name=”SomeTextBox” or x:Name=”SomeTextBox”. |
3 Comments
Emil
nice one but what is {Binding .}. I am searching explanation for this one but I cant find it?
Ryan Versaw
@batmaci I want to say it's equivalent to
{Binding }, but it's been quite a few years since I've worked much with Xaml, so I'm not sure.
mins
@batmaci, years later...
{Binding string} is similar to {Binding Path=string}. string is not used to initialize the property Path directly, but as a parameter for the constructor Binding (string path) which then initializes Path property. This works only when the string is the first token after Binding, the rest being regular initializers (property=value pairs). Knowing that, Binding . is in effect equal to Binding Path=. and property Path syntax is available here.This is shorthand for binding to the current source. For more info see here.
From the documentation specifically:
Optionally, a period (.) path can be used to bind to the current source. For example,
Text="{Binding}"is equivalent toText="{Binding Path=.}".
7 Comments
micahtan
@Ray - my thoughts exactly. If you're going to shorthand, why stop there?
Sergey Aldoukhov
I can't argue with MSDN, but there still a difference. {Binding} cannot be used on an object itself (being two way it requires a property) while {Binding Path=.} works.
micahtan
@Sergey - Do you have a code sample where {Binding} doesn't work but {Binding Path=.} does? If so, MSDN probably needs to get updated...
Sergey Aldoukhov
Easily: var s = "test; DataContext=s; and in <TextBox Text={Binding}/> - does not work. But MSDN is not wiki...
Nicolas
Another exemple : <TextBlock Text="{Binding Converter=...}"/> does not work because you have to set the Path. In that case Path=. is useful.
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