ImageMapEventArgs ImageMapEventArgs ImageMapEventArgs ImageMapEventArgs Class

Definition

Provides data for the Click event of an ImageMap control.

public ref class ImageMapEventArgs : EventArgs
public class ImageMapEventArgs : EventArgs
type ImageMapEventArgs = class
    inherit EventArgs
Public Class ImageMapEventArgs
Inherits EventArgs
Inheritance
ImageMapEventArgsImageMapEventArgsImageMapEventArgsImageMapEventArgs

Examples

The following code example demonstrates how to create an event handler for the Click event. The ImageMap control contains two RectangleHotSpot objects. The ImageMap.HotSpotMode property is set to HotSpotMode.PostBack, which causes the page to post back to the server each time a user clicks one of the RectangleHotSpot objects. The Click event is handled by the VoteMap_Clicked event handler. The VoteMap_Clicked examines the PostBackValue property, sent in the ImageMapEventArgs data, to determine which RectangleHotSpot object is associated with the event. For this example to work correctly, you must supply your own image for the ImageUrl property and update the path to the image appropriately so that the application can locate it.

<%@ 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>

Remarks

The Click event is raised when a HotSpot object in an ImageMap control is clicked. To allow a HotSpot object to raise the Click event, you must first set either the ImageMap.HotSpotMode property or the HotSpot.HotSpotMode property to HotSpotMode.PostBack. To control the actions programmatically that are performed when a postback HotSpot is clicked, provide an event handler for the Click event.

A PostBackValue property stores a string that is associated with the behavior of the HotSpot object when clicked. This string is passed in the ImageMapEventArgs event data when the HotSpot is clicked.

Constructors

ImageMapEventArgs(String) ImageMapEventArgs(String) ImageMapEventArgs(String) ImageMapEventArgs(String)

Initializes a new instance of the ImageMapEventArgs class.

Properties

PostBackValue PostBackValue PostBackValue PostBackValue

Gets the String assigned to the PostBackValue property of the HotSpot object that was clicked.

Methods

Equals(Object) Equals(Object) Equals(Object) Equals(Object)

Determines whether the specified object is equal to the current object.

(Inherited from Object)
GetHashCode() GetHashCode() GetHashCode() GetHashCode()

Serves as the default hash function.

(Inherited from Object)
GetType() GetType() GetType() GetType()

Gets the Type of the current instance.

(Inherited from Object)
MemberwiseClone() MemberwiseClone() MemberwiseClone() MemberwiseClone()

Creates a shallow copy of the current Object.

(Inherited from Object)
ToString() ToString() ToString() ToString()

Returns a string that represents the current object.

(Inherited from Object)

Applies to

See Also