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Listing 7.5 - PropertyRandomImage.ascx

Illustrates how to expose a property from a user control and set the property both declaratively and programmatically.

Listing 7.5 - PropertyRandomImage.ascx (C#)
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<%@ Control Language="C#" ClassName="PropertyRandomImage" %>
<%@ Import Namespace="System.IO" %>
<script runat="server">

    private string _imageFolderPath = "Images"; 

    public string ImageFolderPath
    {
        get { return _imageFolderPath; }
        set { _imageFolderPath = value; }
    }

    void Page_Load()
    {
        string imageToDisplay = GetRandomImage();
        imgRandom.ImageUrl = Path.Combine(_imageFolderPath, imageToDisplay);
        lblRandom.Text = imageToDisplay;
    }

    private string GetRandomImage()
    {
        Random rnd = new Random();
        string[] images = Directory.GetFiles(MapPath("Images"), "*.jpg");
        string imageToDisplay = images[rnd.Next(images.Length)];
        return Path.GetFileName(imageToDisplay);
    }
</script>

<asp:Image
    id="imgRandom"
    Width="300px"
    Runat="server" />
<br />    
<asp:Label  
    id="lblRandom"
    Runat="server" />

The following page sets the property exposed by the user control declaratively.

Listing 7.6 - ShowDeclarative.aspx (C#)
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<%@ Page Language="C#" %>
<%@ Register TagPrefix="user" TagName="PropertyRandomImage" Src="PropertyRandomImage.ascx" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
<head id="Head1" runat="server">
    <title>Show Declarative</title>
</head>
<body>
    <form id="form1" runat="server">
    <div>
    
    <user:PropertyRandomImage
        ID="PropertyRandomImage1"
        ImageFolderPath="Images2"
        Runat="server" />
    
    </div>
    </form>
</body>
</html>

The following page sets the property exposed by the user control programmatically.

Listing 7.7 - ShowProgrammatic.aspx (C#)
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<%@ Page Language="C#" %>
<%@ Register TagPrefix="user" TagName="PropertyRandomImage" Src="PropertyRandomImage.ascx" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
<script runat="server">

    protected void Page_Load(object sender, EventArgs e)
    {
        PropertyRandomImage1.ImageFolderPath = "Images2";
    }
</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head id="Head1" runat="server">
    <title>Show Programmatic</title>
</head>
<body>
    <form id="form1" runat="server">
    <div>
    
    <user:PropertyRandomImage
        ID="PropertyRandomImage1"
        Runat="server" />
    
    </div>
    </form>
</body>
</html>