Pr le yes/no, je sais pas ms sinon pr un alert, la meilleurs solution c'est de faire:
Public Sub alert(ByVal sMessage As String)
Try
Dim sCode As New System.Text.StringBuilder()
With sCode
.Append("<script language='javascript'>" )
.Append("alert('" & sMessage.Replace("'", "\'" ) & "';" )
.Append("</script>" )
End With
If Not oPage.IsStartupScriptRegistered("codeAlert" ) Then
oPage.RegisterStartupScript("codeAlert", sCode.ToString())
End If
Catch
Throw New Exception()
End Try
End Sub
oPage étant l'objet page en cours