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ADO.NET 也是 .NET 框架的组成部分。ADO.NET 用于处理数据访问。通过 ADO.NET,您可以操作数据库。
数据库连接 - 绑定到 DataList 控件
<%@ Import Namespace="System.Data.OleDb" %> <script runat="server"> sub Page_Load dim dbconn,sql,dbcomm,dbread dbconn=New OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;data source=" & server.mappath("/db/northwind.mdb")) dbconn.Open() sql="SELECT * FROM customers" dbcomm=New OleDbCommand(sql,dbconn) dbread=dbcomm.ExecuteReader() customers.DataSource=dbread customers.DataBind() dbread.Close() dbconn.Close() end sub </script> <!DOCTYPE html> <html> <body> <form runat="server"> <asp:DataList id="customers" runat="server" cellpadding="2" cellspacing="2" borderstyle="inset" backcolor="#e8e8e8" width="100%" headerstyle-font-name="Verdana" headerstyle-font-size="12pt" headerstyle-horizontalalign="center" headerstyle-font-bold="True" itemstyle-backcolor="#778899" itemstyle-forecolor="#ffffff" footerstyle-font-size="9pt" footerstyle-font-italic="True"> <HeaderTemplate> Customers Table </HeaderTemplate> <ItemTemplate> <%#Container.DataItem("companyname")%> in <%#Container.DataItem("address")%>, <%#Container.DataItem("city")%> </ItemTemplate> <FooterTemplate> Source: Northwind Database </FooterTemplate> </asp:DataList> </form> </body> </html>
数据库连接 - 绑定到 Repeater 控件
<%@ Import Namespace="System.Data.OleDb" %> <script runat="server"> sub Page_Load dim dbconn,sql,dbcomm,dbread dbconn=New OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;data source=" & server.mappath("/db/northwind.mdb")) dbconn.Open() sql="SELECT * FROM customers" dbcomm=New OleDbCommand(sql,dbconn) dbread=dbcomm.ExecuteReader() customers.DataSource=dbread customers.DataBind() dbread.Close() dbconn.Close() end sub </script> <!DOCTYPE html> <html> <body> <form runat="server"> <asp:Repeater id="customers" runat="server"> <HeaderTemplate> <table border="1" width="100%"> <tr bgcolor="#b0c4de"> <th>Companyname</th> <th>Contactname</th> <th>Address</th> <th>City</th> </tr> </HeaderTemplate> <ItemTemplate> <tr bgcolor="#f0f0f0"> <td><%#Container.DataItem("companyname")%> </td> <td><%#Container.DataItem("contactname")%> </td> <td><%#Container.DataItem("address")%> </td> <td><%#Container.DataItem("city")%> </td> </tr> </ItemTemplate> <FooterTemplate> </table> </FooterTemplate> </asp:Repeater> </form> </body> </html>
在我们的实例中,我们将使用 Northwind 数据库。
首先,导入 "System.Data.OleDb" 命名空间。我们需要这个命名空间来操作 Microsoft Access 和其他 OLE DB 数据库提供商。我们将在 Page_Load 子例程中创建这个数据库的连接。我们创建一个 dbconn 变量,并为其赋值一个新的 OleDbConnection 类,这个类带有指示 OLE DB 提供商和数据库位置的连接字符串。然后我们打开数据库连接:
<%@ Import Namespace="System.Data.OleDb" %>
<script runat="server">
sub Page_Load
dim dbconn
dbconn=New OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;
data source=" & server.mappath("northwind.mdb"))
dbconn.Open()
end sub
</script>
注释:这个连接字符串必须是没有折行的连续字符串!
为了指定需从数据库取回的记录,我们将创建一个 dbcomm 变量,并为其赋值一个新的 OleDbCommand 类。这个 OleDbCommand 类用于发出针对数据库表的 SQL 查询:
<%@ Import Namespace="System.Data.OleDb" %>
<script runat="server">
sub Page_Load
dim dbconn,sql,dbcomm
dbconn=New OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;
data source=" & server.mappath("northwind.mdb"))
dbconn.Open()
sql="SELECT * FROM customers"
dbcomm=New OleDbCommand(sql,dbconn)
end sub
</script>
OleDbDataReader 类用于从数据源中读取记录流。DataReader 是通过调用 OleDbCommand 对象的 ExecuteReader 方法来创建的:
<%@ Import Namespace="System.Data.OleDb" %>
<script runat="server">
sub Page_Load
dim dbconn,sql,dbcomm,dbread
dbconn=New OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;
data source=" & server.mappath("northwind.mdb"))
dbconn.Open()
sql="SELECT * FROM customers"
dbcomm=New OleDbCommand(sql,dbconn)
dbread=dbcomm.ExecuteReader()
end sub
</script>
然后,我们绑定 DataReader 到 Repeater 控件:
<%@ Import Namespace="System.Data.OleDb" %>
<script runat="server">
sub Page_Load
dim dbconn,sql,dbcomm,dbread
dbconn=New OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;
data source=" & server.mappath("northwind.mdb"))
dbconn.Open()
sql="SELECT * FROM customers"
dbcomm=New OleDbCommand(sql,dbconn)
dbread=dbcomm.ExecuteReader()
customers.DataSource=dbread
customers.DataBind()
dbread.Close()
dbconn.Close()
end sub
</script>
<html>
<body>
<form runat="server">
<asp:Repeater id="customers" runat="server">
<HeaderTemplate>
<table border="1" width="100%">
<tr>
<th>Companyname</th>
<th>Contactname</th>
<th>Address</th>
<th>City</th>
</tr>
</HeaderTemplate>
<ItemTemplate>
<tr>
<td><%#Container.DataItem("companyname")%></td>
<td><%#Container.DataItem("contactname")%></td>
<td><%#Container.DataItem("address")%></td>
<td><%#Container.DataItem("city")%></td>
</tr>
</ItemTemplate>
<FooterTemplate>
</table>
</FooterTemplate>
</asp:Repeater>
</form>
</body>
</html>
如果不再需要访问数据库,请记得关闭 DataReader 和数据库连接:
dbread.Close()
dbconn.Close()