ASP.NET FAQ - Collections and Lists

<asp:DataGrid AllowSorting =True OnSortCommand='SortData' id='DataGrid1' runat='server' EnableViewState='false'></asp:DataGrid>

VB.NET

Private Sub Page_Load(sender As Object, e As System.EventArgs)
   ’ Put user code to initialize the page here
   	Dim arrlist As New ArrayList()
	arrlist.Add('Tips')
	arrlist.Add('Tricks')
	arrlist.Add('Code')
	arrlist.Add('Samples')
	DataGrid1.DataSource = arrlist
	DataGrid1.DataBind()
	ViewState('AList') = arrlist
End Sub ’Page_Load

Protected Sub SortData([source] As [Object], e As System.Web.UI.WebControls.DataGridSortCommandEventArgs)
	If ViewState('SortOrder') Is Nothing Then
      		SortAsc()
   	Else
		If ViewState('SortOrder').ToString() = ' ASC' Then
			SortDesc()
      		Else
         			SortAsc()
      		End If
   	End If
End Sub ’SortData
 
Sub SortAsc()
	ViewState('SortOrder') = ' ASC'
	CType(ViewState('AList'), ArrayList).Sort()
	DataGrid1.DataSource = ViewState('AList')
	DataGrid1.DataBind()
	ViewState('Sort') = 'DESC'
End Sub ’SortAsc

Sub SortDesc()
	ViewState('SortOrder') = ' DESC'
	CType(ViewState('AList'), ArrayList).Sort()
	CType(ViewState('AList'), ArrayList).Reverse()
	DataGrid1.DataSource = ViewState('AList')
	DataGrid1.DataBind()
	ViewState('Sort') = 'ASC'
End Sub ’SortDesc

C#

private void Page_Load(object sender, System.EventArgs e)
{
	// Put user code to initialize the page here
	ArrayList arrlist = new ArrayList ();
	arrlist.Add ('Tips');
	arrlist.Add ('Tricks');
	arrlist.Add ('Code');
	arrlist.Add ('Samples');
	DataGrid1.DataSource = arrlist ;
	DataGrid1.DataBind ();
	ViewState['AList'] = arrlist ;
}

protected void SortData(Object source,  System.Web.UI.WebControls.DataGridSortCommandEventArgs  e )
{
	if (ViewState['SortOrder'] ==null)
	{
		SortAsc();
	}
	else if (ViewState['SortOrder'].ToString () == ' ASC' )
	{
		SortDesc();
	}
	else
	{
		SortAsc();
	}
}

void SortAsc()
{
	ViewState['SortOrder'] = ' ASC';
	((ArrayList)ViewState['AList']).Sort ();
	DataGrid1.DataSource = ViewState['AList'];
	DataGrid1.DataBind ();
	ViewState['Sort']='DESC';
}

void SortDesc()
{
	ViewState['SortOrder'] = ' DESC';
	((ArrayList)ViewState['AList']).Sort ();
	((ArrayList)ViewState['AList']).Reverse ();
	DataGrid1.DataSource = ViewState['AList'];
	DataGrid1.DataBind ();
	ViewState['Sort']='ASC';
}

<asp:Button id='btnAsc' runat='server' Text='Asc'></asp:Button>
<asp:ListBox id='ListBox1' runat='server'></asp:ListBox>
<asp:Button id='btnDesc' runat='server' Text='Desc'></asp:Button>

VB.NET

Private Sub Page_Load(sender As Object, e As System.EventArgs)
   ’ Put user code to initialize the page here
   	Dim arrlist As New ArrayList()
   	arrlist.Add('Tips')
   	arrlist.Add('Tricks')
   	arrlist.Add('Code')
   	arrlist.Add('Samples')
   	ListBox1.DataSource = arrlist
   	ListBox1.DataBind()
   	ViewState('AList') = arrlist
End Sub ’Page_Load


Private Sub btnAsc_Click(sender As Object, e As System.EventArgs)
   	CType(ViewState('AList'), ArrayList).Sort()
	ListBox1.DataSource = CType(ViewState('AList'), ArrayList)
	ListBox1.DataBind()
End Sub ’btnAsc_Click

Private Sub btnDesc_Click(sender As Object, e As System.EventArgs)
	CType(ViewState('AList'), ArrayList).Sort()
	CType(ViewState('AList'), ArrayList).Reverse()
	ListBox1.DataSource = CType(ViewState('AList'), ArrayList)
	ListBox1.DataBind()
End Sub ’btnDesc_Click

C#

private void Page_Load(object sender, System.EventArgs e)
{
	// Put user code to initialize the page here
	ArrayList arrlist = new ArrayList ();
	arrlist.Add ('Tips');
	arrlist.Add ('Tricks');
	arrlist.Add ('Code');
	arrlist.Add ('Samples');
	ListBox1.DataSource =arrlist ;
	ListBox1.DataBind ();
	ViewState['AList'] = arrlist ;
}

private void btnAsc_Click(object sender, System.EventArgs e)
{
	((ArrayList)ViewState['AList']).Sort() ;
	ListBox1.DataSource =(ArrayList)ViewState['AList'] ;
	ListBox1.DataBind ();
}

private void btnDesc_Click(object sender, System.EventArgs e)
{	
	((ArrayList)ViewState['AList']).Sort() ;
	((ArrayList)ViewState['AList']).Reverse ();
	ListBox1.DataSource =(ArrayList)ViewState['AList'] ;
	ListBox1.DataBind ();
}

Set the AutoGenerateColumns property of the DataGrid to False.Sample code below
VB.NET

<asp:DataGrid AutoGenerateColumns=False   id='DataGrid1' runat='server'>
<Columns >
	<asp:TemplateColumn HeaderText='HashTable'>
		 <ItemTemplate>
                		<%# Container.DataItem.Key %> <br>
		                <%# Container.DataItem.Value %>
		</ItemTemplate>
	</asp:TemplateColumn>
</Columns>
</asp:DataGrid>

’In Page_Load
Dim ht As New Hashtable()
ht.Add('emp1', 'A')
ht.Add('emp2', 'B')
ht.Add('emp3', 'C')

DataGrid1.DataSource = ht
DataGrid1.DataBind()

C#

<asp:DataGrid AutoGenerateColumns=False   id='DataGrid1' runat='server'>
<Columns >
	<asp:TemplateColumn HeaderText='HashTable'>
		<ItemTemplate>
		                <%# ((DictionaryEntry)Container.DataItem).Key %><br>
		                <%# ((DictionaryEntry)Container.DataItem).Value %>
	               </ItemTemplate>
	</asp:TemplateColumn>
</Columns>
</asp:DataGrid>

//In Page_Load
Hashtable ht = new Hashtable();
ht.Add ('emp1', 'A');
ht.Add ('emp2', 'B');
ht.Add ('emp3', 'C');

DataGrid1.DataSource = ht;
DataGrid1.DataBind();

VB.NET

if arrList= 0 then
..
else
..
end if

C#

if (arrList ==0)
{
...
}
else
{
...
}

VB.NET

Dim arrList As ArrayList = New ArrayList
arrList.Add('Faq')
arrList.Add('Tips')
arrList.Add('Tricks')
DropDownList1.DataSource = arrList
DropDownList1.DataBind()

C#

ArrayList arrList    = new ArrayList();
arrList.Add('Faq');
arrList.Add('Tips');
arrList.Add('Tricks');
DropDownList1.DataSource = arrList;
DropDownList1.DataBind();