Asp.Net Menu. deleting an Item in Runtime

Sometimes we need to delete (hide) a menu item from an aspnet web application menu (or submenu) when a particolar condition occurs. The problem is that the menu component doesn't have a method to hide a menuitem during runtime. Well, here you have the code to do it:

Protected Sub Menu1_PreRender(ByVal sender As Object, ByVal e As System.EventArgs) Handles Menu1.PreRender
    If CONDITION Then
        'delete the unnecessary menu item
        Dim tot As Integer = Menu1.Items.Count - 1
        Dim i As Integer = 0
            While i <= tot
            Dim ss As MenuItem = Menu1.Items(i)
            If ss.Text.ToLower = "menu name" Then
                'delete sub menus
                Dim subtot As Integer = Menu1.Items(i).ChildItems.Count - 1
                Dim j As Integer = 0
                While j <= subtot
                    Menu1.Items(i).ChildItems.RemoveAt(0)
                    j += 1
                End While
                'delete menu
                Menu1.Items.Remove(ss)
                i = i - 1
                tot = tot - 1
            End If
            i += 1
        End While
    End If
End Sub

Asp.Net Menu problem with Chome, Safari and Opera

In the past I published another post regarding the malfunction of Asp.Net Menu componente with IE8. Now I write about this component problems with other browsers: Chrome, Safari and Opera.

With these browsers the menu doesn't work properly, it disappears when clicked.

To made it work, add this code snippet in every page that contains a menu definition, into Page_Init event:

[VB.Net]
If Request.UserAgent.Contains("AppleWebKit") Then
    Request.Browser.Adapters.Clear()
End If

[C#]
If Request.UserAgent.Contains("AppleWebKit") Request.Browser.Adapters.Clear() ;

Read and Write with Cassandra in Vb.Net

This is a first example of application in vb.net that write and read datas using Cassandra and HectorSharp interface(http://hectorsharp.com/). Just download HectorSharp and compile it to create libraries for your project. Obviously, we need to create a referenco to the HectorSharp library in our project before we can use it.

In this example we use the default keyspace of Cassandra (Keyspace1) and also a default Cassandta column family (Standard1).

We'll create a column called "MyColumn" in the column family and we'll put in a value.

For this purpose, we'll use a Web Application with label, called “lbltest”, where we'll show data picked from Cassandra.

Imports HectorSharp

[…]

'db connection
Dim cf As New KeyedCassandraClientFactory(New CassandraClientPoolFactory().Create(), _

New KeyedCassandraClientFactory.Config())
Dim client = cf.Make(New Endpoint("localhost", 9160))

'db definition (keyspace)
Dim keyspace = client.GetKeyspace("Keyspace1")

'Dim path = New ColumnPath(columnfamily name, supercolumn name (if present), column name)
Dim path = New ColumnPath("Standard1", "", "MyColumn")

'insert a value in db
keyspace.Insert("0", path, "My new value")

'get the value
Dim column As Column = keyspace.GetColumn("0", path)

lbltest.Text = column.Value

How you can see, working with Cassandra using HectorSharp is really simple.

Installing Cassandra in Windows

Installing Cassandra Project (http://cassandra.apache.org/)on Windows is really simple, maybe more the do it on Linux.

Cassandra is a BD engine written in Java, the only requirements to install it is Java 1.6 (Is better to use the most up-to-date version).

After installing Java, download the tar.gz archive for the official site and then untar it in the chosen folder (For this example we use "C:\Cassandra").

Well, now just do a bit of configuration. Open "C:\Cassandra\conf\storage-conf.xml" and change default value of the nodes below to:

<commitlogdirectory>C:\Cassandra\commitlog</commitlogdirectory>
<datafiledirectories>
<datafiledirectory>C:\Cassandra\data</datafiledirectory>
</datafiledirectories>

Note: normally is better to use two different disks for commit logs and datas.


Finally, we have to set "CASSANDRA_HOME" as system variable with value "C:\Cassandra"

So, now we can launch "C:\Cassandra\bin\cassandra.bat" to start the Cassandra Server.

Ok, at this point the Cassandra server will be "up-n-running".


To test it, we can launch "C:\Cassandra\bin\cassandra-cli.bat" and then give the command:

connect localhost/9160

If all works, we'll have this answer: "Connected to: "Test Cluster" in localhost/9160"

Enjoy :)

Create a link from command prompt

To create a link to a file or a folder we generally use the GUI. For particular issues (script, batch files) is possible to use shell commands.

Commands are:

mklink "Link Name" c:\Folder\SubFolder\filename.txt

or

mklink "Link Name" c:\Folder\SubFolder


These commands create a link called "Link Name" that refers to the specified folder or file.

Warning: the link will be created in the folder where the command runs.