Sample Code: Grouping Data in the DataList

One of the most common question is that if a Datalist displays the data as

Inside Sales Coordinator 
Callahan 
Sales Manager 
Buchanan 
Sales Representative 
Suyama 
Sales Representative 
King 
Sales Representative
Davolio 
Sales Representative 
Leverling 
Sales Representative 
Peacock 
Sales Representative 
Dodsworth 
Vice President, Sales 
Fuller

 

How to display the result in a way that :

Sales Manager,Sales Representative...etc appear only once. 

Inside Sales Coordinator 
Callahan 
Sales Manager 
Buchanan 
Sales Representative 
Suyama 
King 
Davolio 
Leverling 
Peacock 
Dodsworth 
Vice President, Sales 
Fuller

 

Here goes the code 

HTML Source

<asp:DataList id="DataList1" runat="server">
<HeaderTemplate >
    <table width=100%>
</HeaderTemplate>
<ItemTemplate>
   <tr><td>
   <asp:Label Runat=server
   text=<%#DataBinder.Eval(Container.DataITem, "Title")%> ID="lblTitle">
   </asp:Label>
   <td><asp:Label Runat=server
   text=<%#DataBinder.Eval(Container.DataITem, "LastName")%> ID="lblLastName">
   </asp:Label>
</ItemTemplate>
<FooterTemplate>
   </table>
</FooterTemplate>
</asp:DataList>

Code Behind 

Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs) Handles MyBase.Load 
If Not Page.IsPostBack Then 
  BindTitle() 
End If 
End Sub  

Sub BindTitle() 
  Dim ds As New DataSet() 
  Dim sqlStmt As String = "SELECT * FROM Employees order by title" 
  Dim conString As String = "server=localhost;database=Northwind;uid=sa;pwd=;" 
  Dim myda As SqlDataAdapter = New SqlDataAdapter(sqlStmt, conString) 
  myda.Fill(ds, "Table") 
  DataList1.DataSource = ds 
  DataList1.DataBind() 
End Sub 

Private Sub DataList1_ItemDataBound(ByVal sender As Object, _ 
ByVal e As System.Web.UI.WebControls.DataListItemEventArgs) Handles DataList1.ItemDataBound 
If e.Item.ItemType = ListItemType.AlternatingItem Or e.Item.ItemType = ListItemType.Item Then 
  Dim strval As String = CType(e.Item.FindControl("lblTitle"), Label).Text 
  Dim title As String = ViewState("title") 
  If title = strval Then 
    CType(e.Item.FindControl("lblTitle"), Label).Text = "" 
    e.Item.Visible = False 
  Else 
    title = strval 
    ViewState("title") = title 
    CType(e.Item.FindControl("lblTitle"), Label).Text = title 
    e.Item.Visible = True 
  End If 
End If 
End Sub