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Declarative programming (for which User Controls are designed) doesn't translate well into imperative object construction. Why not create an adapter User Control (or server control) that makes SomeControl easier to use by the legacy code? Like the following. Say we have a legacy page that has a lot of logic in terms of SqlDateTime, and we write some new control that does its work in terms of plain-old DateTime.

LegacyPage.aspx:

<%@ Page Language="C#" AutoEventWireup="true"  %>
<%@ Register Src="~/SomeControlLegacyAdapter.ascx" TagName="SomeControlLegacyAdapter" TagPrefix="test" %>
<script type="text/C#" runat="server">
    protected void Page_Load(object sender, EventArgs e)
    {
        SomeControlLegacyAdatper1.Time = new System.Data.SqlTypes.SqlDateTime(DateTime.Now);
    }
</script>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"&gt;

<html xmlns="http://www.w3.org/1999/xhtml"&gt;
<head runat="server">
    <title></title>
</head>
<body>
    <form id="form1" runat="server">
    <div>
        <test:SomeControlLegacyAdapter runat="server" ID="SomeControlLegacyAdatper1" />
    </div>
    </form>
</body>
</html>

SomeControlLegacyAdapter.ascx

<%@ Control Language="C#" AutoEventWireup="true" %>
<%@ Import Namespace="System.Data.SqlTypes"%>
<%@ Register Src="~/SomeControl.ascx" TagPrefix="test" TagName="SomeControl" %>

<script type="text/C#" runat="server">
    public SqlDateTime Time
    {
        get { return SomeControl1.Time; }
        set { SomeControl1.Time = (DateTime)value; }
    }
</script>

<test:SomeControl ID="SomeControl1" runat="server" />

SomeControl.aspx

<%@ Control Language="C#" AutoEventWireup="true" %>
<script type="text/C#" runat="server">
    public DateTime Time
    {
        get { return string.IsNullOrEmpty(output.Text) ? DateTime.MinValue : DateTime.Parse(output.Text); }
        set { output.Text = value.ToString(); }
    }
</script>

<asp:Literal runat="server" id="output" />

The legacy adapter converts SomeControl into a form easier for LegacyPage to consume.

gWiz 2010-02-10 21:25:11

ansaurus

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answers:

Factory Pattern for User Controls

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