ASP.NET Tutorial/ASP.net Controls/DropDownList
Содержание
Dynamically generating a DropDownList control from an array (C#)
<source lang="csharp">
<%@ Page Language="C#" %> <script runat="server">
protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e) { string[] CarArray = new string[4] {"Ford", "Honda", "BMW", "Dodge"}; string[] AirplaneArray = new string[3] {"Boeing 777", "Boeing 747","Boeing 737"}; string[] TrainArray = new string[3] {"Bullet Train", "Amtrack", "Tram"}; if (DropDownList1.SelectedValue == "Car") { DropDownList2.DataSource = CarArray; } else if (DropDownList1.SelectedValue == "Airplane") { DropDownList2.DataSource = AirplaneArray; } else { DropDownList2.DataSource = TrainArray; } DropDownList2.DataBind(); DropDownList2.Visible = true; } protected void Button1_Click(object sender, EventArgs e) { Response.Write("You selected " + DropDownList1.SelectedValue.ToString() + ": " + DropDownList2.SelectedValue.ToString() + ""); }
</script>
<html xmlns="http://www.w3.org/1999/xhtml" > <head id="Head1" runat="server">
<title>DropDownList Page</title>
</head> <body>
<form id="form1" runat="server">
Select transportation type:
<asp:DropDownList ID="DropDownList1" Runat="server" OnSelectedIndexChanged="DropDownList1_SelectedIndexChanged" AutoPostBack="true"> <asp:ListItem>Select an Item</asp:ListItem> <asp:ListItem>Car</asp:ListItem> <asp:ListItem>Airplane</asp:ListItem> <asp:ListItem>Train</asp:ListItem> </asp:DropDownList> <asp:DropDownList ID="DropDownList2" Runat="server" Visible="false"> </asp:DropDownList> <asp:Button ID="Button1" Runat="server" Text="Select Options" OnClick="Button1_Click" />
</form>
</body> </html></source>
Dynamically generating a DropDownList control from an array (VB)
<source lang="csharp">
<%@ Page Language="VB" %> <script runat="server">
Protected Sub DropDownList1_SelectedIndexChanged(ByVal sender As Object, _ ByVal e As System.EventArgs) Dim CarArray() As String = {"Ford", "Honda", "BMW", "Dodge"} Dim AirplaneArray() As String = {"Boeing 777", "Boeing 747", "Boeing 737"} Dim TrainArray() As String = {"Bullet Train", "Amtrack", "Tram"} If DropDownList1.SelectedValue = "Car" Then DropDownList2.DataSource = CarArray ElseIf DropDownList1.SelectedValue = "Airplane" Then DropDownList2.DataSource = AirplaneArray Else DropDownList2.DataSource = TrainArray End If DropDownList2.DataBind() DropDownList2.Visible = True End Sub Protected Sub Button1_Click(ByVal sender As Object, _ ByVal e As System.EventArgs) Response.Write("You selected " & _ DropDownList1.SelectedValue.ToString() & ": " & _ DropDownList2.SelectedValue.ToString() & "") End Sub
</script> <html xmlns="http://www.w3.org/1999/xhtml" > <head id="Head1" runat="server">
<title>DropDownList Page</title>
</head> <body>
<form id="form1" runat="server">
Select transportation type:
<asp:DropDownList ID="DropDownList1" Runat="server" OnSelectedIndexChanged="DropDownList1_SelectedIndexChanged" AutoPostBack="true"> <asp:ListItem>Select an Item</asp:ListItem> <asp:ListItem>Car</asp:ListItem> <asp:ListItem>Airplane</asp:ListItem> <asp:ListItem>Train</asp:ListItem> </asp:DropDownList> <asp:DropDownList ID="DropDownList2" Runat="server" Visible="false"> </asp:DropDownList> <asp:Button ID="Button1" Runat="server" Text="Select Options" OnClick="Button1_Click" />
</form>
</body> </html></source>
Get selected index from asp:dropdownlist
<source lang="csharp">
<%@ Page Language="VB" AutoEventWireup="false" CodeFile="Default.aspx.vb" Inherits="MyPage" %> <html xmlns="http://www.w3.org/1999/xhtml" > <head runat="server">
<title>Untitled Page</title>
</head> <body>
<form id="form1" runat="server">
<asp:Label ID="Label1" runat="server" Style="z-index: 100; left: 151px; position: absolute; top: 120px" Text="What is the date"></asp:Label> <asp:Label ID="result" runat="server" Height="25px" Style="z-index: 101; left: 159px; position: absolute; top: 242px" Text="Label" Width="324px"></asp:Label> <asp:DropDownList ID="DropDownList1" runat="server" AutoPostBack="True" Height="48px" Style="z-index: 102; left: 274px; position: absolute; top: 118px" Width="243px"> </asp:DropDownList> <asp:Button ID="Button1" runat="server" Style="z-index: 104; left: 393px; position: absolute; top: 168px" Text="OK" />
</form>
</body> </html>
File: Default.aspx.vb
Partial Class MyPage
Inherits System.Web.UI.Page Protected Sub Button1_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles Button1.Click Select Case Me.DropDownList1.SelectedIndex Case 0 Me.result.Text = "A" Case 1 Me.result.Text = "B" Case 2 Me.result.Text = "C" Case 3 Me.result.Text = "D" Case 4 Me.result.Text = "E" Case 5 Me.result.Text = "F" Case 6 Me.result.Text = "G" Case 7 Me.result.Text = "H" Case 8 Me.result.Text = "I" Case 9 Me.result.Text = "J" Case 10 Me.result.Text = "K" Case 11 Me.result.Text = "L" End Select End Sub Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load If Page.IsPostBack = False Then Me.DropDownList1.Items.Add("A") Me.DropDownList1.Items.Add("B") Me.DropDownList1.Items.Add("C") Me.DropDownList1.Items.Add("D") Me.DropDownList1.Items.Add("E") Me.DropDownList1.Items.Add("F") Me.DropDownList1.Items.Add("G") Me.DropDownList1.Items.Add("H") Me.DropDownList1.Items.Add("I") Me.DropDownList1.Items.Add("J") Me.DropDownList1.Items.Add("K") Me.DropDownList1.Items.Add("L") End If End Sub
End Class</source>
Get selected item in DropDownList
<source lang="csharp">
<%@ Page Language="VB" AutoEventWireup="false" CodeFile="Default.aspx.vb" Inherits="DropDownList" %> <!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" > <head runat="server">
<title>Untitled Page</title>
</head> <body>
<form id="form1" runat="server">
What is your favorite ice cream flavor? <asp:DropDownList ID="flavors" runat="server"> <asp:ListItem>A</asp:ListItem> <asp:ListItem>B</asp:ListItem> <asp:ListItem>C</asp:ListItem> </asp:DropDownList><asp:Label ID="results" runat="server"></asp:Label>
<asp:Button ID="btnSubmit" runat="server" Text="Click Me" />
</form>
</body> </html>
File: Default.aspx.vb
Partial Class DropDownList
Inherits System.Web.UI.Page Protected Sub btnSubmit_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnSubmit.Click results.Text = "You like " & flavors.SelectedItem.Text End Sub
End Class</source>