c#数据绑定之linq使用示例
作者：
本实例以MS AdventureWorks2008Entities数据库为基础，演示了LINQ TO ENTITY、LINQ TO ENTITYSQL和LINQ TO ENTITYCLIENT。
XAML：
复制代码 代码如下:
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="2*"/>
<ColumnDefinition Width="8*"/>
</Grid.ColumnDefinitions>
<Grid.RowDefinitions>
<RowDefinition />
<RowDefinition />
<RowDefinition />
</Grid.RowDefinitions>
<ListBox Grid.Column="1" Margin="10" Name="listBox1" />
<Button Content="LinqToEntity" Grid.Column="0" Margin="5" Name="button1" Click="button1_Click" />
<ListBox Grid.Column="1" Grid.Row="1" Margin="10" Name="listBox2" />
<Button Content="LinqToSQL" Grid.Column="0" Grid.Row="1" Margin="5" Name="button2" Click="button2_Click" />
<ListBox Grid.Column="1" Grid.Row="2" Margin="10" Name="listBox3" />
<Button Content="LinToEnClient" Grid.Column="0" Grid.Row="2" Margin="5" Name="button3" Click="button3_Click" />
</Grid>
Button1 LINQ TO ENTITY
复制代码 代码如下:
using (var context = new AdventureWorks2008Entities())
{
//var people = context.People.Where(c => c.LastName == "King").OrderBy(d => d.FirstName).Select(r => new { r.FirstName,r.LastName});
//var people = context.People.Where(c => c.LastName == "King").OrderBy(c =>c.FirstName).Select(c => new { c.FirstName, c.LastName });
var people = from per in context.People
//join emp in context.Employees on per.BusinessEntityID equals emp.BusinessEntityID
where per.LastName == "King"
orderby per.FirstName
select new { per.FirstName, per.LastName};
foreach (var person in people)
{
listBox1.Items.Add(string.Format("{0} \t \t {1} ", person.FirstName, person.LastName));
}
}
Button2 LINQ TO ENTITYSQL
复制代码 代码如下:
using (var context = new AdventureWorks2008Entities())
{
var str = "SELECT VALUE p FROM AdventureWorks2008Entities.People AS p WHERE p.LastName= @LastName Order by p.FirstName";
//var people = context.CreateQuery<Person>(str);
var people = new System.Data.Objects.ObjectQuery<Person>(str, context);
people.Parameters.Add(new System.Data.Objects.ObjectParameter("LastName", "King"));
foreach (var person in people)
{
listBox2.Items.Add(string.Format("{0} \t \t{1}", person.FirstName, person.LastName));
}
}
Button3 LINQ TO ENTITYCLIENT
复制代码 代码如下:
var firstName = "";
var lastName = "";
using (EntityConnection conn = new EntityConnection("name=AdventureWorks2008Entities"))
{
string str = "SELECT p.FirstName, p.LastName FROM AdventureWorks2008Entities.People AS p WHERE p.LastName='King' Order by p.FirstName";
conn.Open();
EntityCommand cmd = conn.CreateCommand();
cmd.CommandText =str;
using (EntityDataReader rdr = cmd.ExecuteReader(System.Data.CommandBehavior.SequentialAccess))
{
while (rdr.Read())
{
firstName = rdr.GetString(0);
lastName = rdr.GetString(1);
listBox3.Items.Add(string.Format("{0}\t \t{1}", firstName, lastName));
}
}
conn.Close();
}
}