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Working at Server-side

Using the server-side API, you can programmatically find, add, remove, disable, or select items in RadListBox.

Adding items

Use the Add method of the RadListBoxItemCollection object to add items programmatically:

protected void Page_Load(object sender, EventArgs e)
{
   if (!IsPostBack)
   {
       RadListBoxItem item = new RadListBoxItem("Item 1", "1");
       RadListBox1.Items.Add(item);
       //copy the first item
       RadListBoxItem item2 = item.Clone();
       RadListBox1.Items.Add(item2);
       //make the third item disabled
       RadListBoxItem item3 = new RadListBoxItem();
       item3.Text = "Item 3";
       item3.Value = "3";
       item3.Enabled = false;
       RadListBox1.Items.Add(item3);
   }
}       
Protected Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs)
    If Not IsPostBack Then
        Dim item As New RadListBoxItem("Item 1", "1")
        RadListBox1.Items.Add(item)
        'copy the first item
        Dim item2 As RadListBoxItem = item.Clone()
        RadListBox1.Items.Add(item2)
        'make the third item disabled
        Dim item3 As New RadListBoxItem()
        item3.Text = "Item 3"
        item3.Value = "3"
        item3.Enabled = False
        RadListBox1.Items.Add(item3)
    End If
End Sub

Removing items

Use the Remove method of the RadListBoxItemCollection object to remove items:

RadListBoxItem itemToRemove = RadListBox1.FindItemByText("Item 3");
RadListBox1.Items.Remove(itemToRemove);     
Dim itemToRemove As RadListBoxItem = RadListBox1.FindItemByText("Item 3")
RadListBox1.Items.Remove(itemToRemove)  

Sorting items

Use the SortItems method of RadListBox object to sort items:

RadListBox1.Sort = RadListBoxSort.Ascending;
RadListBox1.SortItems();
RadListBox1.Sort = RadListBoxSort.Ascending
RadListBox1.SortItems()

You can also use the Sort method of the RadListBoxItemCollection object to sort items:

RadListBox1.Items.Sort();
RadListBox1.Items.Sort()    

You can pass an object of type IComparer as an argument of the function:

protected void Button1_Click(object sender, EventArgs e)
{
    RadListBox1.Items.Sort(new CustomComparer());
}

public class CustomComparer : System.Collections.IComparer
{
    public CustomComparer() { }

    public int Compare(object x, object y)
    {
        RadListBoxItem ItemX = (RadListBoxItem)x;
        RadListBoxItem ItemY = (RadListBoxItem)y;

        return ItemX.Text.CompareTo(ItemY.Text);
    }
}   
    Protected Sub Button1_Click(sender As Object, e As EventArgs)
        RadListBox1.Items.Sort(New CustomComparer())
    End Sub

    Public Class CustomComparer
        Implements System.Collections.IComparer
        Public Sub New()
        End Sub

        Public Function Compare(x As Object, y As Object) As Integer
            Dim ItemX As RadListBoxItem = DirectCast(x, RadListBoxItem)
            Dim ItemY As RadListBoxItem = DirectCast(y, RadListBoxItem)

            Return ItemX.Text.CompareTo(ItemY.Text)
        End Function
    End Class

You can also use a lambda expression as an argument:

    RadListBox1.Items.Sort(item => item.Text);  
    RadListBox1.Items.Sort(Function(item) item.Text)    

Disabling items

Use the Enable property of the RadListBoxItem object to enable or disable an item:

    RadListBoxItem itemToDisable = RadListBox1.FindItemByText("Item 3");
    itemToDisable.Enabled = false;
    RadListBox1.Items[0].Enabled = false;
    Dim itemToDisable As RadListBoxItem = RadListBox1.FindItemByText("Item 3")
    itemToDisable.Enabled = False
    RadListBox1.Items(0).Enabled = False 

Selecting items

Use the Selected property of an item to select it, or use the SelectedIndex property of RadListBox. Note that to select multiple items you need to set the SelectionMode="Multiple" property.

    RadListBoxItem itemToSelect = RadListBox1.FindItemByText("Item 3");
    itemToSelect.Selected = true;
    RadListBox1.Items[0].Selected = true;
    Dim itemToSelect As RadListBoxItem = RadListBox1.FindItemByText("Item 3")
    itemToSelect.Selected = True
    RadListBox1.Items(0).Selected = True 

Finding items

You can locate an item by searching on the Text or Value properties. You can retrieve either the index of the item or a reference to the item itself. Use the following RadListBox methods:

  • FindItemByText

  • FindItemByValue

  • FindItemIndexByValue

Collections of items

You can use the following collections of RadListBoxItem objects:

  • Items - retrieves a list of all items

  • SelectedItems - retrieves a list of all selected items

  • CheckedItems - retrieves a list of all checked items (when the CheckBoxes property is True)

See Also