Bindings for WPF DataGrid visibility

Scenario: Displays some columns in the DataGrid based on the configuration file.

Problem: The Columns collection is just a property of the DataGrid, which is not visible in the logical tree or the visual tree, and does not inherit the DataContext property.

Through the online access to a variety of information, methods can be attributed to the following several, the following will be shown.

Method One: Attach DataContext property to DataGridColumn

The method needs to use a helper class (a global instance needs to be created), with the following details:

 Public classDatagridcontexthelper {StaticDatagridcontexthelper () {DependencyProperty DP= FrameworkElement.DataContextProperty.AddOwner (typeof(DataGridColumn)); FrameworkElement.DataContextProperty.OverrideMetadata (typeof(DataGrid),NewFrameworkpropertymetadata (NULL, Frameworkpropertymetadataoptions.inherits,NewPropertychangedcallback (ondatacontextchanged)); }         Public Static voidondatacontextchanged (DependencyObject D, DependencyPropertyChangedEventArgs e) {DataGrid grid = d asDataGrid; if(Grid! =NULL)            {                foreach(DataGridColumn Colinchgrid. Columns) {Col.                SetValue (Frameworkelement.datacontextproperty, E.newvalue); }            }        }    } 

Sample foreground bindings

<datagridtextcolumn x:name="col2" header="testcolumn "                                     Visibility="{Binding (frameworkelement.datacontext). Show,relativesource={relativesource self},converter={staticresource cc}}"></ Datagridtextcolumn>

Example of a background binding

var New Binding ();             = Bindingmode.oneway;            Binding. RelativeSource=new  RelativeSource (relativesourcemode.self);             New Booleantovisibilityconverter ();            Binding. Path=new PropertyPath ("(Frameworkelement.datacontext). Show");            Bindingoperations.setbinding (obj, datagridcolumn.visibilityproperty, binding);

Method Two: Bind directly to the VM via source

Example code:

var New Binding ();             = Bindingmode.oneway;             = vm;             New Booleantovisibilityconverter ();             New PropertyPath ("Show");            Bindingoperations.setbinding (obj, datagridcolumn.visibilityproperty, binding);

Method Three: Bind with a proxy class for the VM through source

proxy class

Freezable can inherit DataContext even if they are not in the visual tree or the logical tree

 Public classbindingproxy:freezable {#regionOverrides of Freezableprotected OverrideFreezable Createinstancecore () {return NewBindingproxy (); }        #endregion         Public ObjectData {Get{return(Object) GetValue (Dataproperty); }            Set{SetValue (dataproperty, value);} }         Public Static ReadOnlyDependencyProperty Dataproperty =Dependencyproperty.register ("Data",typeof(Object),                                         typeof(Bindingproxy)); }

Foreground binding Code

<datagrid x:name="DG"Horizontalalignment=" Left"Verticalalignment="Top"height="253"Width="436"Itemssource="{Binding Persons}"AutoGenerateColumns="False"> <DataGrid.Resources><dgtest:bindingproxy x:key="proxy" data="{Binding}  "/></DataGrid.Resources> <DataGrid.Columns> <datagridtextcolumn x:name="col1"Header="Testcolumn"binding="{Binding Name}"></DataGridTextColumn> <datagridtextcolumn x:name="col2"Header="Testcolumn"Visibility="{Binding (frameworkelement.datacontext). Show,relativesource={relativesource self},converter={staticresource cc}}"></DataGridTextColumn><datagridtextcolumn x:name="col3" header="testcolumn
    
      " 
      Visibility=
     "
     {Binding Data.show,source={staticresource PR Oxy},converter={staticresource cc}}
     "></DataGridTextColumn>
    </DataGrid.Columns> </DataGrid>

Method Four: Through a proxy control to implement

A proxy control is similar to a proxy object because it can inherit the DataContext property, but one that is seen in the logical tree. Examples are as follows:

<frameworkelement x:name="dummyelement"visibility="collapsed"/> <DataGrid> <DataGrid.Columns> <datagridtextcolumn header="Test"Binding="{Binding Name}"Visibility="{Binding datacontext.isenable,Source={x:reference Dummyelement}}"/></DataGrid.Columns> </DataGrid>

Bindings for WPF DataGrid visibility