以下是问题：
private void editTaskButton_Click(object sender, RoutedEventArgs e)
{
// Cast the parameter as a button.
var button = sender as Button;
if (button != null)
{
// Get a handle for the to-do item bound to the button.
ToDoItem toDoEdit = button.DataContext as ToDoItem;
// I need to get toDoEdit handle to the EditTaskPage so that I can work on it
NavigationService.Navigate(new Uri("/EditTaskPage.xaml", UriKind.Relative));
}
}
我需要在EditTaskPage（windows phone page）上使用toDoEdit句柄（从列表框中） 这样做最简单，最有效的方法是什么？请具体说明。我是第一次使用Windows Phone本地数据库。
这是我的ToDoItem的样子：
public class ToDoDataContext : DataContext
{
// Pass the connection string to the base class.
public ToDoDataContext(string connectionString)
: base(connectionString)
{ }
// Specify a table for the to-do items.
public Table<ToDoItem> Items;
// Specify a table for the categories.
public Table<ToDoCategory> Categories;
}
ToDoDataContext.cs：
using System;
using System.ComponentModel;
using System.Data.Linq;
using System.Data.Linq.Mapping;
namespace project
{
public class ToDoDataContext : DataContext
{
// Pass the connection string to the base class.
public ToDoDataContext(string connectionString)
: base(connectionString)
{ }
// Specify a table for the to-do items.
public Table<ToDoItem> Items;
// Specify a table for the categories.
public Table<ToDoCategory> Categories;
}
[Table]
public class ToDoItem : INotifyPropertyChanged, INotifyPropertyChanging
{
// Define ID: private field, public property, and database column.
private int _toDoItemId;
[Column(IsPrimaryKey = true, IsDbGenerated = true, DbType = "INT NOT NULL Identity", CanBeNull = false, AutoSync = AutoSync.OnInsert)]
public int ToDoItemId
{
get { return _toDoItemId; }
set
{
if (_toDoItemId != value)
{
NotifyPropertyChanging("ToDoItemId");
_toDoItemId = value;
NotifyPropertyChanged("ToDoItemId");
}
}
}
// Define item name: private field, public property, and database column.
private string _itemName;
[Column]
public string ItemName
{
get { return _itemName; }
set
{
if (_itemName != value)
{
NotifyPropertyChanging("ItemName");
_itemName = value;
NotifyPropertyChanged("ItemName");
}
}
}
// Define completion value: private field, public property, and database column.
private bool _isComplete;
[Column]
public bool IsComplete
{
get { return _isComplete; }
set
{
if (_isComplete != value)
{
NotifyPropertyChanging("IsComplete");
_isComplete = value;
NotifyPropertyChanged("IsComplete");
}
}
}
// Version column aids update performance.
[Column(IsVersion = true)]
private Binary _version;
// Internal column for the associated ToDoCategory ID value
[Column]
internal int _categoryId;
// Entity reference, to identify the ToDoCategory "storage" table
private EntityRef<ToDoCategory> _category;
// Association, to describe the relationship between this key and that "storage" table
[Association(Storage = "_category", ThisKey = "_categoryId", OtherKey = "Id", IsForeignKey = true)]
public ToDoCategory Category
{
get { return _category.Entity; }
set
{
NotifyPropertyChanging("Category");
_category.Entity = value;
if (value != null)
{
_categoryId = value.Id;
}
NotifyPropertyChanging("Category");
}
}
#region INotifyPropertyChanged Members
public event PropertyChangedEventHandler PropertyChanged;
// Used to notify that a property changed
private void NotifyPropertyChanged(string propertyName)
{
if (PropertyChanged != null)
{
PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
}
}
#endregion
#region INotifyPropertyChanging Members
public event PropertyChangingEventHandler PropertyChanging;
// Used to notify that a property is about to change
private void NotifyPropertyChanging(string propertyName)
{
if (PropertyChanging != null)
{
PropertyChanging(this, new PropertyChangingEventArgs(propertyName));
}
}
#endregion
}
[Table]
public class ToDoCategory : INotifyPropertyChanged, INotifyPropertyChanging
{
// Define ID: private field, public property, and database column.
private int _id;
[Column(DbType = "INT NOT NULL IDENTITY", IsDbGenerated = true, IsPrimaryKey = true)]
public int Id
{
get { return _id; }
set
{
NotifyPropertyChanging("Id");
_id = value;
NotifyPropertyChanged("Id");
}
}
// Define category name: private field, public property, and database column.
private string _name;
[Column]
public string Name
{
get { return _name; }
set
{
NotifyPropertyChanging("Name");
_name = value;
NotifyPropertyChanged("Name");
}
}
// Version column aids update performance.
[Column(IsVersion = true)]
private Binary _version;
// Define the entity set for the collection side of the relationship.
private EntitySet<ToDoItem> _todos;
[Association(Storage = "_todos", OtherKey = "_categoryId", ThisKey = "Id")]
public EntitySet<ToDoItem> ToDos
{
get { return this._todos; }
set { this._todos.Assign(value); }
}
// Assign handlers for the add and remove operations, respectively.
public ToDoCategory()
{
_todos = new EntitySet<ToDoItem>(
new Action<ToDoItem>(this.attach_ToDo),
new Action<ToDoItem>(this.detach_ToDo)
);
}
// Called during an add operation
private void attach_ToDo(ToDoItem toDo)
{
NotifyPropertyChanging("ToDoItem");
toDo.Category = this;
}
// Called during a remove operation
private void detach_ToDo(ToDoItem toDo)
{
NotifyPropertyChanging("ToDoItem");
toDo.Category = null;
}
#region INotifyPropertyChanged Members
public event PropertyChangedEventHandler PropertyChanged;
// Used to notify that a property changed
private void NotifyPropertyChanged(string propertyName)
{
if (PropertyChanged != null)
{
PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
}
}
#endregion
#region INotifyPropertyChanging Members
public event PropertyChangingEventHandler PropertyChanging;
// Used to notify that a property is about to change
private void NotifyPropertyChanging(string propertyName)
{
if (PropertyChanging != null)
{
PropertyChanging(this, new PropertyChangingEventArgs(propertyName));
}
}
#endregion
}
}
答案 0 :(得分：1)
有多种方法可以做到这一点，这里有两个：
NavigationService.Navigate(new Uri("/EditTaskPage.xaml?id=" + toDoEdit.Id , UriKind.Relative));并检索EditTaskPage中的项目。