asp.net เรียกใช้ DropDownList จาก Database เป็นการดึงค่า DataSoruce
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Date :
31 Mar 2547 18:53:38
By :
master
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3249
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1
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Code (VB.NET)
'*** DropDownList & DataTable ***'
Function DropDownListDataTable()
Dim objConn As OleDbConnection
Dim dtAdapter As OleDbDataAdapter
Dim dt As New DataTable
Dim strConnString As String
strConnString = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source="& _
Server.MapPath("database/mydatabase.mdb")&";"
objConn = New OleDbConnection(strConnString)
objConn.Open()
Dim strSQL As String
strSQL = "SELECT * FROM country"
dtAdapter = New OleDbDataAdapter(strSQL, objConn)
dtAdapter.Fill(dt)
dtAdapter = Nothing
objConn.Close()
objConn = Nothing
'*** DropDownlist ***'
With Me.myDDL1
.DataSource = dt
.DataTextField = "CountryName"
.DataValueField = "CountryCode"
.DataBind()
End With
'*** Default Value ***'
myDDL1.SelectedIndex = myDDL1.Items.IndexOf(myDDL1.Items.FindByValue("TH")) '*** By DataValueField ***'
'myDDL1.SelectedIndex = myDDL1.Items.IndexOf(myDDL1.Items.FindByText("Thailand")) '*** By DataTextField ***'
End Function
<%@ Page Language="VB" AutoEventWireup="True" %>
<%@ Import Namespace="System.Data" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
<script runat="server" >
Sub Selection_Change(sender as Object, e As EventArgs)
' Set the background color for days in the Calendar control
' based on the value selected by the user from the
' DropDownList control.
Calendar1.DayStyle.BackColor = _
System.Drawing.Color.FromName(ColorList.SelectedItem.Value)
End Sub
Sub Page_Load(sender as Object, e As EventArgs)
' Load data for the DropDownList control only once, when the
' page is first loaded.
If Not IsPostBack Then
' Specify the data source and field names for the Text
' and Value properties of the items (ListItem objects)
' in the DropDownList control.
ColorList.DataSource = CreateDataSource()
ColorList.DataTextField = "ColorTextField"
ColorList.DataValueField = "ColorValueField"
' Bind the data to the control.
ColorList.DataBind()
' Set the default selected item, if desired.
ColorList.SelectedIndex = 0
End If
End Sub
Function CreateDataSource() As ICollection
' Create a table to store data for the DropDownList control.
Dim dt As DataTable = New DataTable()
' Define the columns of the table.
dt.Columns.Add(new DataColumn("ColorTextField", GetType(String)))
dt.Columns.Add(new DataColumn("ColorValueField", GetType(String)))
' Populate the table with sample values.
dt.Rows.Add(CreateRow("White", "White", dt))
dt.Rows.Add(CreateRow("Silver", "Silver", dt))
dt.Rows.Add(CreateRow("Dark Gray", "DarkGray", dt))
dt.Rows.Add(CreateRow("Khaki", "Khaki", dt))
dt.Rows.Add(CreateRow("Dark Khaki", "DarkKhaki", dt))
' Create a DataView from the DataTable to act as the data source
' for the DropDownList control.
Dim dv As DataView = New DataView(dt)
Return dv
End Function
Function CreateRow(Text As String, Value As String, dt As DataTable) As DataRow
' Create a DataRow using the DataTable defined in the
' CreateDataSource method.
Dim dr As DataRow = dt.NewRow()
' This DataRow contains the ColorTextField and ColorValueField
' fields, as defined in the CreateDataSource method. Set the
' fields with the appropriate value. Remember that column 0
' is defined as ColorTextField, and column 1 is defined as
' ColorValueField.
dr(0) = Text
dr(1) = Value
Return dr
End Function
</script>
<head runat="server">
<title> DropDownList Data Binding Example </title>
</head>
<body>
<form id="form1" runat="server">
<h3> DropDownList Data Binding Example </h3>
Select a background color for days in the calendar.
<br /><br />
<asp:Calendar id="Calendar1"
ShowGridLines="True"
ShowTitle="True"
runat="server"/>
<br /><br />
<table cellpadding="5">
<tr>
<td>
Background color:
</td>
</tr>
<tr>
<td>
<asp:DropDownList id="ColorList"
AutoPostBack="True"
OnSelectedIndexChanged="Selection_Change"
runat="server"/>
</td>
</tr>
</table>
</form>
</body>
</html>
Load balance : Server 04
