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| Displaying Pop-up Alert Messages |
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Register and show pop-up alert messages even if the current page is redirected.
- Jing Ding, Senior Systems Consultant for The Ohio State University Medical Center
June 20, 2008
Iron Speed Designer V5.X
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| Introduction |
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It is common to display confirmation pop-up messages after a task is successfully completed.
Examples are after you send an email or save changes to a page. You can implement pop-ups using
ScriptManager.RegisterStartupScript() or Iron Speed Designer’s shortcut method MiscUtils.RegisterJScriptAlert().
The pop-up, however, will not work if the page is redirected after completion of a task. This
is because the JavaScript code is emitted to the current page, not the destination page. In
this article, I show you how to implement roaming alert messages, i.e. to display pop-up alert
even if the page is redirected.
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| Solution |
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The idea is fairly easy. Leave the alert message in session, and let the next page (either
the current page or the redirect page) pick it up. The BaseApplicationPage class is the best
place to implement the method so that all Iron Speed Designer-generated pages are roaming-ready.
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| Implementation |
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Open BaseApplicationPage.cs (.vb) in either Visual Studio or Iron Speed Designer. This file is located in:
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...\<App Name>\App_Code\Shared\BaseApplicationPage.cs (.vb)
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To make the method available to every new Iron Speed Designer application, put it in the code templates folder, usually:
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C:\Program Files\Iron Speed\Designer vX.X.X\ProjectTemplates\vs200X\cs(vb)\App_Code\Shared
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Add the following RegisterAlert() method in the BaseApplicationPage class.
C#:
public void RegisterAlert(string key, string msg, bool roaming) {
if (!roaming) {
MiscUtils.RegisterJScriptAlert(this, key, msg);
} else {
Hashtable AlertQueue = this.Session["AlertQueue"] as Hashtable;
if (AlertQueue == null)
this.Session["AlertQueue"] = AlertQueue = new Hashtable();
AlertQueue.Add(key, msg);
}
}
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Visual Basic .NET:
Public Sub RegisterAlert(ByVal key As String, ByVal msg As String, ByVal roaming As Boolean)
If Not roaming Then
MiscUtils.RegisterJScriptAlert(Me, key, msg)
Else
Dim AlertQueue As Hashtable = TryCast(Me.Session("AlertQueue"), Hashtable)
If AlertQueue = Nothing Then
AlertQueue = New Hashtable()
Me.Session("AlertQueue") = AlertQueue
End If
AlertQueue.Add(key, msg)
End If
End Sub
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Locate the Control_ClearControls_PreRender() event handler in the BaseApplicationPage class.
Insert the code block “Display alert messages”.
C#:
protected void Control_ClearControls_PreRender(object sender, EventArgs e) {
this.ClearControlsFromSession();
// Display alert messages
Hashtable AlertQueue = this.Session["AlertQueue"] as Hashtable;
if (AlertQueue != null) {
foreach (Object key in AlertQueue.Keys) {
string msg = AlertQueue[key] as string;
MiscUtils.RegisterJScriptAlert(this, (string)key, msg);
}
AlertQueue.Clear();
}
}
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Visual Basic .NET:
Protected Sub Control_ClearControls_PreRender(ByVal sender As Object, ByVal e As EventArgs)
Me.ClearControlsFromSession()
' Display alert messages
Dim AlertQueue As Hashtable = TryCast(Me.Session("AlertQueue"), Hashtable)
If AlertQueue <> Nothing Then
For Each key As Object In AlertQueue.Keys
Dim msg As String = TryCast(AlertQueue(key), String)
MiscUtils.RegisterJScriptAlert(Me, DirectCast(key, String), msg)
Next
AlertQueue.Clear()
End If
End Sub
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Save and rebuild. Your application is now roaming ready.
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| About the Author |
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Jing Ding has a PhD in Computer Engineering, Bioinformatics and Computational Biology, and an M.S. in Toxicology
from Iowa State University. He received his B.S. in biophysics from Fundan University in Shanghai, China. He is a
self-taught programmer who "played" with assembly, C and C++ in the 1990s. He took a break from programming from
1997 to 2000. When he picked it up again in 2001, he worked with Java. Jing began working with C# and .NET in 2006.
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