LINQ to Object first experience (using object replace the two-dimensional array for data filtering)

VS2008 inside a magical thing called LINQ, can handle a variety of data through the same grammatical way (SQL, XML, Object, ...), a small meow this first experience to feel this thing , really well, first experience to be a simple test, look at the small of his right meow

VS2008 inside a magical thing called LINQ, can handle a variety of data through the same grammatical way (SQL, XML, Object, ...), a small meow this first experience to feel this thing , really well, first experience to be a simple test, look at the small of his right meow

First look at a map of LINQ architecture (Source: Cao teacher briefing in St. progenitor of TechEd2007)

Please select depends on complete drawing above, can be used to achieve considerable LINQ data from this chart, as long as the data can be used in the form of Object process, can be accessed through LINQ

Then began the first experience

First explain small meow do: meow get hold of the seat table, respectively --SeatId (seating Code), SeatName (seat name)
and then generate test data data 200 seats, SeatName (seat name) generates a random number az letters plus SeatId name as a seat, and finally a screen test using LINQ to filter data (look for the same prefix)

This topic before in ASP are small meow do with two-dimensional arrays in .NET which is the way the object can be used to replace two for an array

Object first establish a seat as follows:

_ Public Class Seat Private m_SeatNum As Integer Private m_SeatName As String Public Property SeatNum() Property SeatNum() As Integer Get Return m_SeatNum End Get Set(ByVal value As Integer) m_SeatNum = value End Set End Property Public Property SeatName() Property SeatName() As String Get Return m_SeatName End Get Set(ByVal value As String) m_SeatName = value End Set End Property End Class

Then set the following plan surface

  <table > <tr> <td> <asp:Button runat="server" Text="产生座位数据" /> <asp:GridView runat="server" CellPadding="4" ForeColor="#333333" GridLines="None"> <FooterStyle BackColor="#507CD1" Font-Bold="True" ForeColor="White" /> <RowStyle BackColor="#EFF3FB" /> <PagerStyle BackColor="#2461BF" ForeColor="White" HorizontalAlign="Center" /> <SelectedRowStyle BackColor="#D1DDF1" Font-Bold="True" ForeColor="#333333" /> <HeaderStyle BackColor="#507CD1" Font-Bold="True" ForeColor="White" /> <EditRowStyle BackColor="#2461BF" /> <AlternatingRowStyle BackColor="White" /> </asp:GridView> </td> <td valign="top"> <asp:TextBox runat="server"></asp:TextBox> <asp:Button runat="server" Text="筛选座位名称" /> <asp:GridView runat="server" CellPadding="4" ForeColor="#333333" GridLines="None"> <FooterStyle BackColor="#507CD1" Font-Bold="True" ForeColor="White" /> <RowStyle BackColor="#EFF3FB" /> <PagerStyle BackColor="#2461BF" ForeColor="White" HorizontalAlign="Center" /> <SelectedRowStyle BackColor="#D1DDF1" Font-Bold="True" ForeColor="#333333" /> <HeaderStyle BackColor="#507CD1" Font-Bold="True" ForeColor="White" /> <EditRowStyle BackColor="#2461BF" /> <AlternatingRowStyle BackColor="White" /> </asp:GridView> </td> </tr> </table>

Data generated on GridView1, the filtered data in GridView2

Write data is then generated portion

Protected Sub btnGen_Click() Sub btnGen_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnGen.Click Dim y As Integer Dim s As Seat mySeats.Clear() For y = 1 To 200 s = New Seat s.SeatNum = y s.SeatName = GetRndChr() + "-" + y.ToString mySeats.Add(s) Next ViewState("mySeats") = mySeats Me.GridView1.DataSource = mySeats Me.GridView1.DataBind() End Sub Protected Function GetRndChr() Function GetRndChr() As String Dim i As Integer = 26 Randomize() Dim tmpI As Integer = i * Rnd() + 1 + 96 Return Chr(tmpI) End Function

Then are our focus here, in these data, we want to find SeatName (seat name) at the beginning of a data before small meow may use cycles to check case by case basis, but with LINQ, it can be written in this way

Protected Sub btnSift_Click() Sub btnSift_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnSift.Click Dim Qry As Object = From ss In mySeats _ Where ss.SeatName Like Me.TextBox1.Text + "*" _ Select ss Me.GridView2.DataSource = Qry Me.GridView2.DataBind() End Sub

We can see that with such short program will be able to do the screening. This is great

A friend familiar with T-SQL, you can imagine before then inside T-SQL inside Grou By, Distinct, Order By and so the object can then play, even through JOIN, the various objects associated with the data for later taking data. Really amazing ah.

这次的初体验只是约略的感受一下LINQ的威力，此次的例子只是两个字段，一个条件的筛选，各位可以试想一下，如果应用在很多字段，并且结合其他的数据(LINQ可以使用JOIN)并且使用多重条件的筛选，那么可以节省多少的程序就能够达到相同的目的。未来有其他的测试再与大家分享。

^_^

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原文:大专栏  LINQ to Object初体验(使用对象取代二维数组作数据筛选)