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PolygonHotSpot.GetCoordinates Method

  • Reference

Definition

Namespace:
System.Web.UI.WebControls
Assembly:
System.Web.dll

Returns a string that represents the coordinates of the vertexes of a PolygonHotSpot object.

public:
 override System::String ^ GetCoordinates();
public override string GetCoordinates ();
override this.GetCoordinates : unit -> string
Public Overrides Function GetCoordinates () As String

Returns

String

A string that represents the coordinates of the vertexes of a PolygonHotSpot object. The default value is an empty string ("").

Examples

The following code example demonstrates how to create an ImageMap control that contains three PolygonHotSpot objects. Each PolygonHotSpot object represents a geographical region on the map. When the user clicks a PolygonHotSpot object, it posts back to the server. The GetCoordinates method retrieves the coordinates of the polygon's vertexes so that they can be displayed in a label.

<%@ 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 RegionMap_Clicked (object sender, ImageMapEventArgs e)
  {
    string coordinates;

    // When a user clicks a hot spot, display
    // the hot spot's type and name.
    switch (e.PostBackValue)
    {
      case "Western":
        coordinates = Regions.HotSpots[0].GetCoordinates();
        Message1.Text = "The coordinates are " + coordinates;
        break;
        
      case "Northern":
        coordinates = Regions.HotSpots[1].GetCoordinates();
        Message1.Text = "The coordinates are " + coordinates;
        break;

      case "Southern":
        coordinates = Regions.HotSpots[2].GetCoordinates();
        Message1.Text = "The coordinates are " + coordinates;
        break;

      default:
        Message1.Text = "You did not click a valid hot spot region.";
        break;
    }
  }  
  
</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
<head id="Head1" runat="server">
  <title>PolygonHotSpot.GetCoordinates Example</title>
</head>
  <body>
    <form id="Form1" runat="server">
    
      <h3>PolygonHotSpot.GetCoordinates Example</h3>
      
      <!-- Change or remove the width and height attributes as
           appropriate for your image. -->
      <asp:imagemap id="Regions"           
        imageurl="Images/RegionMap.jpg"
        alternatetext="Sales regions" 
        hotspotmode="PostBack"
        width="400"
        height="400"
        onclick="RegionMap_Clicked"   
        runat="Server">            
          
        <asp:PolygonHotSpot 
          coordinates="0,0,176,0,125,182,227,400,0,400"         
          postbackvalue="Western"
          alternatetext="Western Region">
        </asp:PolygonHotSpot>
          
        <asp:PolygonHotSpot 
          coordinates="177,0,400,0,400,223,335,154,127,180"         
          postbackvalue="Northern"
          alternatetext="Northern Region">
        </asp:PolygonHotSpot>
        
        <asp:PolygonHotSpot 
          coordinates="128,185,335,157,400,224,400,400,228,400"         
          postbackvalue="Southern"
          alternatetext="Southern Region">
        </asp:PolygonHotSpot>
      
      </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 RegionMap_Clicked(ByVal sender As Object, ByVal e As ImageMapEventArgs)
    Dim coordinates As String
        
    ' When a user clicks a hot spot, display
    ' the coordinates of the hot spot's vertices.
    Select Case (e.PostBackValue)
      
      Case ("Western")
        coordinates = Regions.HotSpots(0).GetCoordinates()
        Message1.Text = "The coordinates are " & coordinates
      
      Case ("Northern")
        coordinates = Regions.HotSpots(1).GetCoordinates()
        Message1.Text = "The coordinates are " & coordinates
      
      Case ("Southern")
        coordinates = Regions.HotSpots(2).GetCoordinates()
        Message1.Text = "The coordinates are " & coordinates
      
      Case Else
        Message1.Text = "You did not click a valid hot spot region."
    
    End Select

  End Sub
  
</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
<head id="Head1" runat="server">
  <title>PolygonHotSpot.GetCoordinates Example</title>
</head>
  <body>
    <form id="Form1" runat="server">
    
      <h3>PolygonHotSpot.GetCoordinates Example</h3>
      
      <!-- Change or remove the width and height attributes as
           appropriate for your image. -->
      <asp:imagemap id="Regions"           
        imageurl="Images/RegionMap.jpg"
        alternatetext="Sales regions" 
        hotspotmode="PostBack"
        width="400"
        height="400"
        onclick="RegionMap_Clicked"   
        runat="Server">            
          
        <asp:PolygonHotSpot 
          coordinates="0,0,176,0,125,182,227,400,0,400"         
          postbackvalue="Western"
          alternatetext="Western Region">
        </asp:PolygonHotSpot>
          
        <asp:PolygonHotSpot 
          coordinates="177,0,400,0,400,223,335,154,127,180"         
          postbackvalue="Northern"
          alternatetext="Northern Region">
        </asp:PolygonHotSpot>
        
        <asp:PolygonHotSpot 
          coordinates="128,185,335,157,400,224,400,400,228,400"         
          postbackvalue="Southern"
          alternatetext="Southern Region">
        </asp:PolygonHotSpot>
      
      </asp:imagemap>
            
      <br /><br />
          
      <asp:label id="Message1"
        runat="Server">
      </asp:label>                 
                 
    </form>      
  </body>
</html>

Remarks

The GetCoordinates method returns a string that represents the coordinates of the vertexes of a PolygonHotSpot object. The string this method returns is the current value of the Coordinates property.

The GetCoordinates method is used internally by ASP.NET to get the text to use for the coordinates of a PolygonHotSpot when it is rendered. The string that is returned is specific to the browser and markup language.

Applies to

See also