A preliminary study on the Silverlight framework-viewmodel

The previous article introduced the overall architecture of the mvvm architecture. The following describes the implementation process of viewmodel and riaservice.

1. viewmodel: defines the attributes and Operations corresponding to the view, as follows:

Viewmodelbase. CS, inherited fromInotifypropertychanged. In this way, when the bound view changes, the attributes or methods corresponding to the viewmodel can be triggered.CodeAs follows:

 

Public class viewmodelbase: inotifypropertychanged
{

Protected void onnotifypropertychanged (string P)
{
If (propertychanged! = NULL)
{
Propertychanged (this, new propertychangedeventargs (p ));
}
}

Public bool isdesigntime
{
Get
{
Return (application. Current = NULL) | (application. Current. GetType () = typeof (Application ));
}
}

# Region inotifypropertychanged members

Public event propertychangedeventhandler propertychanged;

# Endregion
}

 

Productionviewmodel. CS, the viewmodel corresponding to the view, inherits from viewmodelbase, the Code is as follows:

Public class productionviewmodel: viewmodelbase
{
Private ienumerable <productiondatadto> _ listproduction; // query result
Private string _ searchtext; // query Condition
Private icommand _ querycommand; // query command

Public icommand querycommand
{
Get {return _ querycommand ;}
}
Public String searchtext
{

Get {return _ searchtext ;}
Set
{
_ Searchtext = value;
Onpolicypropertychanged ("searchtext ");
}
}

Public ienumerable <productiondatadto> listproduction
{
Get {return _ listproduction ;}
Set
{
_ Listproduction = value;
Onnotifypropertychanged ("listproduction ");
}
}

Testdomaincontext service = NULL;
Public productionviewmodel ()
{
_ Querycommand = new querycommand (this );
_ Querycommand. Execute (null );
}

Public void querydata ()
{
Service = new yoctestdomaincontext ();

_ Listproduction = service. Load (service. getproductiondataquery (). entities;

}
}

 

Here, we define an icommand to process the behavior involved in viewmodel. The Code is as follows:

Public partial class querycommand: icommand
{< br> private productionviewmodel _ productionviewmodel;
private string _ searchtext;
Public querycommand (productionviewmodel, string searchtext)
{< br> _ productionviewmodel = productionviewmodel;
_ searchtext = searchtext;
}< br> Public querycommand (productionviewmodel)
{< BR >_productionviewmodel = productionviewmodel;
}

Public bool canexecute (object parameter)
{
Return true;
}

Public event eventhandler canexecutechanged
{
Add {}
Remove {}
}
Public void execute (object parameter)
{
This. _ productionviewmodel. querydata ();
}
}

 

The above is a rough introduction to the viewmodel structure.