How do I sort an arraylist in VB.Net?

Question

Hi everyone,

I have an arraylist which gets populated from a database with two properties: NAME and AGE. How can I sort the arraylist by age, then by name? If I have:
maria 24
jason 30
andy 24
I need it to be sorted by age first, and then by name, so I should get the following result:
andy 24
maria 24
jason 30
(notice andy/maria alphabetically sorted).
I have tried to sort it by a property at a time, but if I do that by the time I've done the second sorting the first one is lost. I kinda need it to act like an SQL-Like ORDER BY, which won't work for me since I need to sort it after the arraylist is populated. Please let me know if you know how I can do that.

Thank you in advance

Answer 1

In the class you are using to store each person, implement the IComparable interface. You will write your own version of CompareTo() that ArrayList.Sort() will use to sort your objects. Here's a link to MSDNs section on IComparable.

http://msdn2.microsoft.com/en-us/system.icomparable.compareto(VS.80).aspx

Answer 2

Vb.net Arraylist Sort

Answer 3

While there are a lot of sort algorhythms out there on the Internet, I'd really suggest to you that you change your approach altogether. Don't use an ArrayList object. Put everything into a DataTable, then call its DataView. Sort algorythms will be slower and less powerful than the hidden xpath queries happening behind the scenes in a DataView, especially since you're talking about a recursive sort.

Dim Fred as new DataTable("MyTable")
Fred.Columns.Add("FirstName")
Fred.Columns.Add("Age",_
System.Type.GetType("System.Integer")
Dim dr as DataRow = dt.NewRow()
dr("Name") = "Wilma"
dr("Age") = 23
dt.Rows.Add(dr)
dr = dt.NewRow()
dr("Name") = "Bob"
dr("Age") = 22
dt.Rows.Add(dr)

DataView dv = dt.DefaultView
dv.Sort = "Name ASC, Age ASC"

DataGrid1.DataSource = dv
DataGrid1.DataBind()

Answer 4

tricky aspect. look into with google. it will help!