ImageMapEventArgs.PostBackValue 屬性
定義
重要
部分資訊涉及發行前產品,在發行之前可能會有大幅修改。 Microsoft 對此處提供的資訊,不做任何明確或隱含的瑕疵擔保。
取得 String,其指派給已按一下 PostBackValue 物件的 HotSpot 屬性。
public:
property System::String ^ PostBackValue { System::String ^ get(); };
public string PostBackValue { get; }
member this.PostBackValue : string
Public ReadOnly Property PostBackValue As String
屬性值
String 指派給已按一下 PostBackValue 物件的 HotSpot 屬性。
範例
下列程式碼範例示範如何建立 Click 事件的事件處理常式。 控制項 ImageMap 包含兩個 RectangleHotSpot 物件。 屬性 ImageMap.HotSpotMode 設定為 HotSpotMode.PostBack
,這會導致每次使用者按一下其中一個 RectangleHotSpot 物件時,頁面回傳至伺服器。 事件 Click 是由 VoteMap_Clicked
事件處理常式處理。 處理常式會 PostBackValue 檢查在資料中 ImageMapEventArgs 傳送的屬性,以判斷與 RectangleHotSpot 事件相關聯的物件。 若要讓這個範例正常運作,您必須提供屬性自己的映射 ImageUrl ,並適當地更新映射的路徑,讓應用程式可以找到它。
<%@ page language="C#" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<script runat="server">
void VoteMap_Clicked (Object sender, ImageMapEventArgs e)
{
string coordinates;
string hotSpotType;
int yescount = ((ViewState["yescount"] != null)? (int)ViewState["yescount"] : 0);
int nocount = ((ViewState["nocount"] != null)? (int)ViewState["nocount"] : 0);
// When a user clicks the "Yes" hot spot,
// display the hot spot's name and coordinates.
if (e.PostBackValue.Contains("Yes"))
{
yescount += 1;
coordinates = Vote.HotSpots[0].GetCoordinates();
hotSpotType = Vote.HotSpots[0].ToString ();
Message1.Text = "You selected " + hotSpotType + " " + e.PostBackValue + ".<br />" +
"The coordinates are " + coordinates + ".<br />" +
"The current vote count is " + yescount.ToString() +
" yes votes and " + nocount.ToString() + " no votes.";
}
// When a user clicks the "No" hot spot,
// display the hot spot's name and coordinates.
else if (e.PostBackValue.Contains("No"))
{
nocount += 1;
coordinates = Vote.HotSpots[1].GetCoordinates();
hotSpotType = Vote.HotSpots[1].ToString ();
Message1.Text = "You selected " + hotSpotType + " " + e.PostBackValue + ".<br />" +
"The coordinates are " + coordinates + ".<br />" +
"The current vote count is " + yescount.ToString() +
" yes votes and " + nocount.ToString() + " no votes.";
}
else
{
Message1.Text = "You did not click a valid hot spot region.";
}
ViewState["yescount"] = yescount;
ViewState["nocount"] = nocount;
}
</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head id="head1" runat="server">
<title>ImageMap Class Post Back Example</title>
</head>
<body>
<form id="form1" runat="server">
<h3>ImageMap Class Post Back Example</h3>
<asp:imagemap id="Vote"
imageurl="Images/VoteImage.jpg"
width="400"
height="200"
alternatetext="Vote Yes or No"
hotspotmode="PostBack"
onclick="VoteMap_Clicked"
runat="Server">
<asp:RectangleHotSpot
top="0"
left="0"
bottom="200"
right="200"
postbackvalue="Yes"
alternatetext="Vote yes">
</asp:RectangleHotSpot>
<asp:RectangleHotSpot
top="0"
left="201"
bottom="200"
right="400"
postbackvalue="No"
alternatetext="Vote no">
</asp:RectangleHotSpot>
</asp:imagemap>
<br /><br />
<asp:label id="Message1"
runat="Server">
</asp:label>
</form>
</body>
</html>
<%@ Page Language="VB" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<script runat="server">
Sub VoteMap_Clicked(ByVal sender As Object, ByVal e As ImageMapEventArgs)
Dim coordinates As String
Dim hotSpotType As String
Dim yescount As Integer
Dim nocount As Integer
If (ViewState("yescount") IsNot Nothing) Then
yescount = Convert.ToInt32(ViewState("yescount"))
Else
yescount = 0
End If
If (ViewState("nocount") IsNot Nothing) Then
nocount = Convert.ToInt32(ViewState("nocount"))
Else
nocount = 0
End If
' When a user clicks the "Yes" hot spot,
' display the hot spot's name and coordinates.
If (e.PostBackValue.Contains("Yes")) Then
yescount += 1
coordinates = Vote.HotSpots(0).GetCoordinates()
hotSpotType = Vote.HotSpots(0).ToString()
Message1.Text = "You selected " & hotSpotType & " " & e.PostBackValue & ".<br />" & _
"The coordinates are " & coordinates & ".<br />" & _
"The current vote count is " & yescount.ToString() & _
" yes votes and " & nocount.ToString() & " no votes."
' When a user clicks the "No" hot spot,
' display the hot spot's name and coordinates.
ElseIf (e.PostBackValue.Contains("No")) Then
nocount += 1
coordinates = Vote.HotSpots.Item(1).GetCoordinates()
hotSpotType = Vote.HotSpots.Item(1).ToString()
Message1.Text = "You selected " & hotSpotType & " " & e.PostBackValue & ".<br />" & _
"The coordinates are " & coordinates & ".<br />" & _
"The current vote count is " & yescount.ToString() & _
" yes votes and " & nocount.ToString() & " no votes."
Else
Message1.Text = "You did not click a valid hot spot region."
End If
ViewState("yescount") = yescount
ViewState("nocount") = nocount
End Sub
</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head id="head1" runat="server">
<title>ImageMap Class Post Back Example</title>
</head>
<body>
<form id="form1" runat="server">
<h3>ImageMap Class Post Back Example</h3>
<asp:imagemap id="Vote"
imageurl="Images/VoteImage.jpg"
width="400"
height="200"
alternatetext="Vote Yes or No"
hotspotmode="PostBack"
onclick="VoteMap_Clicked"
runat="Server">
<asp:RectangleHotSpot
top="0"
left="0"
bottom="200"
right="200"
postbackvalue="Yes"
alternatetext="Vote yes">
</asp:RectangleHotSpot>
<asp:RectangleHotSpot
top="0"
left="201"
bottom="200"
right="400"
postbackvalue="No"
alternatetext="Vote no">
</asp:RectangleHotSpot>
</asp:imagemap>
<br /><br />
<asp:label id="Message1"
runat="Server">
</asp:label>
</form>
</body>
</html>
備註
使用這個屬性,以程式設計方式存取 PostBackValue 按一下控制項中 ImageMap 物件的 屬性 HotSpot 。
適用於
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