wp7.1 使用本地数据库
¹在SQL Server Compact 4.0中，当Ntext 和 image 数据超过256 bytes 时将会保存到一个新的数据页。这会影响到数据库的密度，因为SQL Server Compact 4.0 数据库是按页方式面不是按字节方式来压缩的。
4． 创建工程
新建一个Windows Phone工程，最好是MVVM工程，也就是选择新建工程中的Windows Phone Databound Application 模板直接生成或者手工创建MVVM工程。创建好后，将System.Data.Linq命名空间引入到工程。这个命名空间所在位置\Program Files\Reference Assemblies\Microsoft\Framework\Silverlight\v4.0\Profile\WindowsPhone71中。
5． 创建数据库TP-LINK路由器带MODEM功能吗
新建一个类继承System.Data.Linq.DataContext类，这样就可以用这个类来控制数据库了。
public class MyDataContext : DataContext
{
public const string ConnectionStr = "Data Source=isostore:/MyDB.sdf";
public Table<MyTable> Rows;
public MyDataContext()
: base(ConnectionStr)
{
}
}
在这个类中同时创建数据库表类。
[Table]
public class MyTable : INotifyPropertyChanged, INotifyPropertyChanging
{
private int _index;
[Column(IsPrimaryKey = true, CanBeNull = false, IsDbGenerated = true, DbType = "INT NOT NULL Identity", AutoSync=AutoSync.OnInsert)]
public int Index
{
get
{
return _index;
}
set
{
if (_index != value)
{
NotifyPropertyChanging("Index");
_index = value;
NotifyPropertyChanged("Index");
}
}
}
private string _name;
[Column]
public string Name
{
get
{
return _name;
}
set
{
NotifyPropertyChanging("Name");
_name = value;
NotifyPropertyChanged("Name");
}
}
private String _gen;
[Column]
public String Gen
{
get
{
return _gen;
}
set
{
NotifyPropertyChanging("Gen");
_gen = value;
NotifyPropertyChanged("Gen");
}
}
private int _age;
[Column]
public int Age
{
get
{
return _age;
}
set
{
NotifyPropertyChanging("Age");
_age = value;
NotifyPropertyChanged("Age");
}
}
#region INotifyPropertyChanged Members
public event PropertyChangedEventHandler PropertyChanged;
private void NotifyPropertyChanged(string propertyName)
{
if (PropertyChanged != null)
{
PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
}
}
#endregion
#region INotifyPropertyChanging Members
public event PropertyChangingEventHandler PropertyChanging;
private void NotifyPropertyChanging(string propertyName)
{
if (PropertyChanging != null)
{
PropertyChanging(this, new PropertyChangingEventArgs(propertyName));
}
}
#endregion
}
6． 操作数据库
新建一个ViewModel类，在这个类中实现数据库的操作。在这个类中实现了对数据的选择、保存、更新和删除。在对数据库的操作因为不能直接使用Transact_SQL,所以操作都是通过LINQ来完成的。
MyDataContext _DB;
public void SelectData()
{
if (IsAddedToDB)
{
if (_DB.DatabaseExists())
{
IEnumerator<MyTable> enumerator = _DB.Rows.GetEnumerator();
while (enumerator.MoveNext())
{
this.Items.Add(enumerator.Current);
}
IsAddedToDB = false;
}
}
}
public bool SaveData(MyTable table)
{
try
{
this.Items.Add(table);
_DB.Rows.InsertOnSubmit(table);
_DB.SubmitChanges();
}
catch (Exception e)
{
return false;
}
return true;
}
public bool DeleteData(MyTable table)
{
try
{
if (_DB.DatabaseExists())
{
_DB.Rows.DeleteOnSubmit(table);
_DB.SubmitChanges();
this.Items.Remove(table);
}
}
catch (Exception e)
{
return false;
}
return true;
}
public bool UpdateData(MyTable source, MyTable dest)
{
try
{
var tables = from item in this.Items where (int)item.Index == source.Index select item;
foreach (MyTable mt in tables)
{
mt.Name = dest.Name;
mt.Age = dest.Age;
mt.Gen = dest.Gen;
break;
}
MyTable table = _DB.Rows.GetOriginalEntityState(source);
table.Name = dest.Name;
table.Age = dest.Age;
table.Gen = dest.Gen;
_DB.SubmitChanges();
}
catch (Exception e)
{
return false;
}
return true;
}