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Javascript alert from a vb class in the app_code folder

Posted on 2010-11-29
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Last Modified: 2012-08-13
I developed a class in vb.net  that will be referenced in an ASP.net website. I will distribute the compiled class to my client for him to reference to in his website and call teh methods from his web pages. How can I incorporate in my class a javascript alert if the user encounters an error when calling the public methods that are exposed by my class. I am assuming that it has to do with referencing the httpContext from within the class but I am not sure how to do it. Any idea how to achieve this?
Thanks
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Question by:qwerty360
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6 Comments
 
LVL 82

Assisted Solution

by:leakim971
leakim971 earned 166 total points
ID: 34235542
You can use Response.Write("<SCRIPT LANGUAGE=""JavaScript"">alert('Error encountered!!!')<" & "/" & "SCRIPT>")

More infos here : http://www.java2s.com/Code/ASP/Response/UsingtheResponsetooutputJavascriptcodeVBnet.htm
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LVL 2

Assisted Solution

by:maymounlb
maymounlb earned 167 total points
ID: 34236137
place this sub in the class
    Public Sub JSAlert(ByVal clScript As System.Web.UI.ClientScriptManager, ByVal message As String)
        Dim alertScript As String = "<script type=""text/javascript"">"
        alertScript &= "window.alert('" & message & "');"
        alertScript &= "</script>"

        clScript.RegisterClientScriptBlock(Me.GetType(), "SCRIPTLOGOUT", alertScript)
    End Sub

and call it this way



            class1.JSAlert(ClientScript, "Test") from the pages
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LVL 21

Expert Comment

by:Alpesh Patel
ID: 34236552
Pls Register Script to script manager as scriptblock or startup script.
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LVL 29

Assisted Solution

by:Kumaraswamy R
Kumaraswamy R earned 167 total points
ID: 34238204
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Accepted Solution

by:
qwerty360 earned 0 total points
ID: 34238314
Neither of the above suggestions worked. I took your sugestions a step further and tried the following 2 possibilities but that did not work as well. Now remember that I am not putting code in the web.ui pages. All the code should be in the class. Any other suggestions? thanks.
Public Sub ErrorAlert1(ByVal errorMesage As String)
    Dim myScript As String = "<script type=""text/javascript"">"
    myScript &= "alert('" & errorMesage & "');"
    myScript &= "</script>"
    Dim page As Page = HttpContext.Current.CurrentHandler
    page.Response.Write(myScript)
End Sub


Public Sub ErrorAlert2(ByVal errorMesage As String)
    Dim myScript As String = "alert('" & errorMesage & "');"
    Dim page As Page = HttpContext.Current.CurrentHandler
    If (Not page.ClientScript.IsStartupScriptRegistered("myErrorAlert")) Then
      page.ClientScript.RegisterStartupScript(Me.GetType(), "myErrorAlert", myScript, True)
    End If
End Sub

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Author Closing Comment

by:qwerty360
ID: 34276688
Both methods I am showing actually work. Thanks for your contribution.
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