Send parameter to addhandler?

Question

I have a button in a grid that I created programmatically. The button edits some data in a table using data in a hidden column of the grid that the button is in. Normally I send a hidden field the row data using javascript onclientclick of the button then make the changes to the database using that hidden field. But there must be a way to send the addhandler of the button a parameter. This is the code i have to clarify....

Dim btnedit As New ImageButton
    AddHandler btnedit.Click, AddressOf btnedit_Click
    btnedit.ImageUrl = "\images\bttnEditMini.gif"

If e.Row.RowType <> DataControlRowType.Header And e.Row.RowType <> DataControlRowType.Footer Then
        e.Row.Cells(3).Controls.Add(btnedit)
End If

here is my Addhandler with its delegate:

Public Delegate Sub ImageClickEventHandler(ByVal sender As Object, ByVal e As ImageClickEventArgs)
Sub btnedit_Click(ByVal sender As Object, ByVal e As ImageClickEventArgs)
//programming stuff
End Sub

How can i send this handler a parameter?

Meta-Knight · Answer 1 · 2009-06-04T13:50:41.637

3

By convention, all event handlers accept two parameters: the sender, and the EventArgs. If you need to send custom information to the listeners, create a new class that inherits from EventArgs and contains the information that you need to communicate.

Check out this article on CodeProject that shows you how to do this.

edited Jun 04 '09 at 13:50

answered Jun 02 '09 at 18:52

Meta-Knight

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score 1 · Answer 2 · answered Jun 02 '09 at 18:09

1

Short answer: no. Where would you send it? You've got two parameters.

Longer answer: sender is the control that sent the event. In this case, it will be your btnEdit control. Maybe that will help you.

answered Jun 02 '09 at 18:09

John Saunders

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i understand that. but could i set up the click handler to accept another parameter? if so, what would i pass the other parameters? – Eric Jun 02 '09 at 18:27
No. The handler for an event must always conform to the signature of the event. Additional parameters are not possible. – John Saunders Jun 02 '09 at 22:36

score 0 · Accepted Answer · answered Jun 02 '09 at 21:17

Since it was in a grid i just used the row command instead. And when Row command is used you can send it a commandname and a commandargument. I passed my parameter as the argument.

 GridView1.Rows(i).Cells(3).Controls.Add(btndel)
            btndel.ImageUrl = "\images\bttnDelete.gif"
            btndel.ToolTip = "This will delete the Selected Assignment"
            btndel.CommandName = "destroy"
            btndel.CommandArgument = GridView1.Rows(i).Cells(0).Text
            btndel.Attributes.Add("onclick", "javascript: if(confirm('Are you sure you want to delete this Department Cost Days Assignment?')==false) return false;")

here is the rowcommand:

Protected Sub GridView1_RowCommand(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.GridViewCommandEventArgs) Handles GridView1.RowCommand
    If e.CommandName = "destroy" Then 'used destroy because Delete command was prohibited.
       Call Connection()
        Dbcmd.CommandText = "Delete from table where condition = '" & e.CommandArgument & "'"
        Dbcmd.ExecuteNonQuery()
        Dbconn.Close()
        Dbconn.Dispose()
    End If

score 0 · Answer 4 · answered Jun 03 '09 at 18:15

0

If you don't want to use the 'default'/already defined parameters, you can create your own events.

answered Jun 03 '09 at 18:15

Rob P.

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That sounds interesting. I'll look into that. – Eric Jun 03 '09 at 20:12

Send parameter to addhandler?

4 Answers4