WPF Binding Learning (iii)

http://blog.csdn.net/lisenyang/article/details/183121991. Two-way binding between a control and a control

WPF also supports controls as data sources,

 <textbox name= " txt_source   " width="  120   " horizontalalignment="  left   " ></TextBox> <textbox text=< Span style= "COLOR: #800000" > " {binding Elementname=txt_source,path=text}   " name="   Txt_target   " width="  120  "  horizontalalignment=  " left  "; 

The above code can implement the two-way binding between the controls, and we find that our binding data sources are not source, but elementname.

Of course we can also use code to implement

New Binding ("Text"this. Txt_source};             this. txt_target.setbinding (textbox.textproperty, binding);

Bind the data source using code bindings that we still use for source

2. Multi-level path

WPF supports multi-level paths, that is, we say "dot" in layman's way.

Let's change the code above.

this. txt_target.setbinding (textbox.textproperty, binding);

Note : Because the source and destination data cannot be matched, two-way binding is not possible.

We can see that the data we bind is the length property in the Text property, which is what we call a multilevel path.

3. Index Binding

We know that the collection type is an indexer (Indexer), also known as a parameter attribute. Since it is an attribute, indexers can also be used as path, for example, we want a textbox to display the 1th character of another textbox

New Binding ("text[1]") {Source =this. Txt_source,mode = Bindingmode.oneway};             this. txt_target.setbinding (textbox.textproperty, binding);

4. Collection Bindings

When using a collection or DataView as a data source, if we want to use its default element as a data source, we need to use the following syntax:

list<string> list =Newlist<string> () {"Dog Doll","2 dogs left ."}; Txt_list1.setbinding (Textbox.textproperty,NewBinding ("/") {Source = list, Mode =bindingmode.onetime}); Txt_list2.setbinding (Textbox.textproperty,NewBinding ("/[1]") {Source = List,mode =bindingmode.onetime}); Txt_list3.setbinding (Textbox.textproperty,NewBinding ("/length"{Source = list, Mode = Bindingmode.onetime});

The effect is as follows

If you want to bind a second element, you can use the point directly

list<string> list =Newlist<string> () {"Dog Doll","2 dogs left ."}; Txt_list1.setbinding (Textbox.textproperty,NewBinding ("[1]") {Source = list, Mode =bindingmode.onetime}); Txt_list2.setbinding (Textbox.textproperty,NewBinding ("[1]. [1]") {Source = List,mode =bindingmode.onetime}); Txt_list3.setbinding (Textbox.textproperty,NewBinding ("[1]. Length"{Source = list, Mode = Bindingmode.onetime});

If you want to set the subset of the elements in the path, you can use the multilevel slash method ("slash" down);

We create a type of relationship between provinces and cities

  Public  classProvince { Public stringName {Get;Set; }  PublicIlist<city> Citys {Get;Set; } }     Public classCity { Public stringName {Get;Set; }  PublicIlist<district> Districts {Get;Set; } }     Public classDistrict { Public stringName {Get;Set; } }

Then we use a multi-level slash to bind

list<province> list =NewList<province>()            {                NewProvince {Name="Hebei", Citys=NewList<city>                    {                        NewCity {Name="Handan", districts=Newlist<district>{NewDistrict {name="Hanshan District"} }                        } } } }; Txt_list1.setbinding (Textbox.textproperty,NewBinding ("/name") {Source = list, Mode =bindingmode.onetime}); Txt_list2.setbinding (Textbox.textproperty,NewBinding ("/citys/name") {Source = list, Mode =bindingmode.onetime}); Txt_list3.setbinding (Textbox.textproperty,NewBinding ("/citys/districts/name"{Source = list, Mode = Bindingmode.onetime});

Of course, you can also use multi-level "points" to bind

New Binding ("[0]". Name") {Source = list, Mode =new Binding ("[0]. Citys[0]. Name") {Source = list, Mode =new Binding ("[0]. Citys[0]. Districts[0]. Name") {Source = list, Mode = Bindingmode.onetime});

WPF Binding Learning (iii)